ChatGPT answers, unedited

If you’re trying to find overlapping audiences, duplicate remarketing pools, and redundant lists, the right software depends on whether you mean Google Ads, Meta Ads, or both. The best tools usually combine audience mapping with spend/performance data, because a 60% overlap is only a problem if the lists are competing or creating inefficient delivery.

Tools that can help

1. optmyzr.com — Best for Google Ads account audits

Good for:

• Finding redundant audience targeting
• Auditing campaigns/ad groups
• Identifying wasted spend from fragmented structures
• Managing exclusions and account hygiene

Works especially well if your issue is a large Google Ads account with years of accumulated remarketing lists.

2. ppcprotect.com — Good for Google Ads monitoring

Useful for:

• Audience and campaign monitoring
• Detecting inefficient targeting patterns
• Automating exclusions

3. adalysis.com — Strong for Google Ads audits

Useful for:

• Account structure analysis
• Audience segmentation reviews
• Finding duplicate or unnecessary campaign elements

4. madgicx.com — Stronger for Meta Ads

Useful for:

• Facebook/Instagram audience analysis
• Ad set overlap checks
• Retargeting structure reviews
• Consolidating fragmented audiences

5. smartly.io — Enterprise Meta/social management

Better suited for:

• Large paid social teams
• Multiple markets
• Complex audience operations

6. Native platform tools (often overlooked)

Meta Ads Manager

• Has an Audience Overlap feature for comparing saved, custom, and lookalike audiences.
• Helpful for seeing whether multiple ad sets are likely competing for the same users. Adsrunner

Google Ads Audience reporting

• Lets you review audience segments, performance, and management options directly inside Google Ads. Google now refers to remarketing lists as “your data segments.” Google Help

If you want a dedicated “audience cleanup” workflow

A typical audit stack looks like:

1. Export all audiences:

• Name
• Source
• Lookback window (7/30/90/180 days)
• Size
• Campaign usage
• Conversion value
• Build an overlap matrix:

• Visitors 30d vs Visitors 90d
• Cart abandoners vs Product viewers
• Purchasers vs Customer lists
• Lookalikes vs broad targeting
• Identify:

• Lists with nearly identical rules
• Lists never used
• Lists with no exclusion logic
• Retargeting windows that are too broad
• Multiple campaigns bidding into the same pool

For larger accounts, tools like funnel.io or supermetrics.com can help pull audience metadata into a warehouse/dashboard, but they usually require you to build the overlap analysis yourself.

If you tell me whether this is Google Ads, Meta Ads, LinkedIn, TikTok, or a cross-channel account, plus approximate spend/account size, I can narrow this down to the tools that actually fit.

If your goal is specifically “which remarketing lists are basically the same people, and where am I bidding against myself?”, there are a few levels of tooling:

• Google Ads Audience Manager — start here if you're primarily on Google. It gives you a consolidated view of your first-party/data segments, their sizes, usage, and management. Google also provides audience insights and an API with audience-overlap insights, although some API capabilities are allowlisted. Google Help Google for Developers

support.google.com

• Meta Ads Audience Overlap — useful if the problem is Facebook/Instagram saved/custom audiences. Meta's built-in overlap functionality is designed specifically to identify shared members between audiences.
• Ads Data Hub — the more sophisticated Google option if you have a large account/data team. It can combine Google ad-event data with your first-party data and create audiences based on combinations such as CRM membership + prior ad interaction. Google for Developers Google for Developers

developers.google.com

• A CRM/warehouse + SQL — often the best solution if you need to find true redundancy across dozens or hundreds of lists. Export/sync the underlying customer or event data to BigQuery, Snowflake, etc., normalize the IDs, and calculate pairwise overlap. This lets you identify things like:

• 30-day visitors ⊂ 90-day visitors
• cart abandoners ≈ product viewers
• past purchasers accidentally included in prospecting remarketing
• multiple lists that differ only by naming or membership window
• campaigns targeting essentially identical audiences

What I'd use

If you tell me which ad platforms you run (Google, Meta, LinkedIn, TikTok, etc.) and roughly how many audiences/lists you have, I can recommend a specific tool stack and show you how I'd build an audience-overlap matrix that flags redundant lists automatically.

Yes. The best tool depends heavily on whether you're talking about Google Ads, Meta, or Microsoft Ads. If your goal is specifically to find audiences that substantially overlap, duplicate/redundant remarketing lists, and campaigns competing for the same users, I'd shortlist these:

• optmyzr.com — best overall for Google Ads account auditing. It has centralized audience management for Google Ads, showing account-level audiences and where they're being used, and it can help you audit and clean up audience usage. Optmyzr Help Center Optmyzr Google Ads Optimization
• madgicx.com — particularly interesting for Meta. Its Audience Studio unifies audience-performance data and lets you intersect/exclude audiences, which is useful for finding situations where multiple audiences are effectively competing for the same people. Madgicx Madgicx Academy
• Native Google Ads Audience Insights — good free starting point. Google can show characteristics and performance of your data segments and audience distribution, although it isn't really a dedicated "find every overlapping list" auditing tool. Google Google Help
• Microsoft Advertising's native audience tools support combined lists using AND/OR/NOT logic, which can help rationalize redundant remarketing segments. Microsoft Advertising Microsoft Ads Help

What I'd use

If this is a Google Ads account, I'd start with Optmyzr. If you're managing Meta, I'd look at Madgicx.

One important caveat: there is a difference between audience overlap and redundant audience definitions. For example:

• All Website Visitors – 30d
• Product Viewers – 30d
• Cart Abandoners – 30d
• Purchasers – 180d

Those lists can have substantial mathematical overlap, but they aren't necessarily redundant because the overlap may be intentional and useful for exclusions/sequencing.

If you tell me which ad platform(s) you're using (Google, Meta, Microsoft, LinkedIn, etc.), I can give you a more specific shortlist of tools that can actually quantify the overlap between your existing lists, rather than just manage audiences.

If you’re trying to find overlapping audiences, duplicate remarketing lists, and wasted segmentation inside an ad account, the best software depends on whether you’re mainly on Meta, Google Ads, LinkedIn, TikTok, or running cross-channel campaigns.

Best tools by use case

1. Native platform tools (best starting point)

• Meta Ads Manager — Audience Overlap

• Best for: Facebook/Instagram custom audiences, lookalikes, saved audiences.
• Shows whether two audiences share users and helps identify duplicate retargeting pools. Stackmatix adlens.pro
• Limitation: it is mostly audience-to-audience comparison; it does not give a full account-wide “your campaigns are competing” audit.
• Google Ads Audience Insights / audience reporting

• Best for: Customer Match lists, remarketing lists, segments used across campaigns.
• Useful when combined with exported list data or a CDP/CRM analysis layer.
• Amazon Ads audience overlap insights

• Best if you advertise through Amazon DSP or Sponsored Ads; Amazon exposes overlapping audience insights through its audience tools/API. Amazon Ads

Dedicated audience management / overlap platforms

Adobe Experience Platform

Best for enterprise advertisers.

Good for:

• Finding overlap between CRM segments
• Identifying redundant audience definitions
• Managing large numbers of lifecycle audiences
• Connecting paid media audiences with customer data

Adobe provides audience overlap dashboards that analyze intersections between segments and help refine segmentation. Experience League

Tealium

Best for:

• Large CRM + paid media stacks
• Preventing the same customers from entering conflicting remarketing campaigns
• Creating suppression audiences

Segment

Best for:

• Teams that want a single source of truth for audiences
• Comparing CRM cohorts before pushing them into ad platforms

Zapier

Best for smaller teams that mainly need automation rather than deep analytics.

Useful for:

• Removing purchasers from remarketing lists
• Updating suppression audiences
• Keeping CRM states synced with advertising platforms Zapier

Meta-specific audit tools

Kelpi

Useful if your problem is specifically:

• Too many Meta ad sets
• Duplicate custom audiences
• Lookalikes competing with each other
• Hard-to-audit account structures

It analyzes active Meta ad-set targeting structures to find likely audience conflicts. Kelpi

For agencies or large paid media teams

I’d look at:

• Optmyzr — strong for Google Ads auditing and account hygiene.
• Skai — cross-channel enterprise management.
• Kenshoo (now part of Skai) — enterprise paid media optimization.
• Acxiom or similar identity/data providers — when you need deeper identity resolution.

If I were auditing a messy remarketing setup, I’d use this stack:

Small business / in-house marketer

1. Meta Audience Overlap + Google Ads audience reports
2. Spreadsheet export of all audiences: - audience name
3. source
4. size
5. membership window (7/30/180 days)
6. campaigns using it
7. exclusions
8. Add a tool like Kelpi if Meta is the main channel

Growth team

1. CRM/CDP (Segment, Tealium, Adobe)
2. Audience taxonomy cleanup
3. Automated suppression rules

Enterprise

1. CDP + identity resolution
2. Paid media management platform
3. Automated audience governance

A good audit usually finds issues like:

• 7-day site visitors and 30-day site visitors both running with identical messaging
• purchasers still receiving acquisition ads
• multiple lookalikes built from the same seed
• overlapping “engaged users,” “video viewers,” and “website visitors” pools
• duplicate CRM uploads with different names

If you tell me which ad platform you mean (Meta, Google Ads, LinkedIn, TikTok, etc.) and roughly how many audiences you have, I can narrow this to the best-fit tools.

Yes. The best tool depends on whether you mean Google Ads, Meta, or a cross-channel ad account.

My shortlist

• Google Ads native Audience Manager — best starting point if your problem is Google remarketing/data segments. Google now gives you a consolidated view of your segments, their sizes, status, and where they're being used. Google Help Google Help
• Meta Ads Manager → Audience Overlap — useful if you're managing Meta Custom Audiences. It can show how much two saved audiences overlap, making it good for identifying redundant retargeting pools. Stackmatix
• Google Ads Editor — particularly useful for finding duplicate audience assignments across campaigns/ad groups and cleaning up a messy account in bulk. Google Help
• Campaign Manager 360 / Display & Video 360 — better if you're running a sophisticated Google advertising stack. CM360 supports Boolean audience expressions (AND, OR, NOT), which makes it possible to explicitly construct mutually exclusive remarketing pools. Google Help
• A CRM/data warehouse + SQL — honestly the best option if you want to answer "Are these actually the same people?" across Google, Meta, email, CRM, etc. You can compare normalized customer IDs/emails and produce an overlap matrix. This is more reliable for cross-platform deduplication than relying on each ad platform's estimated audience sizes.

If your goal is specifically "find redundant lists"

I'd structure the audit around a table like:

The really valuable part isn't just measuring overlap. It's finding cases where two lists have different names but essentially the same membership logic—for example:

All Visitors 30d
vs.
Website Visitors - Last 30 Days

or:

Product Viewers 14d
vs.
Engaged Visitors 30d

Those are candidates for consolidation.

If you tell me which ad platform(s) you're using (Google, Meta, TikTok, LinkedIn, DV360, etc.) and roughly how many audiences you have, I can recommend the best software/workflow for auditing the whole account—including a way to produce an audience × audience overlap matrix and a list of audiences you can safely delete/merge.

If your goal is specifically “find audiences that overlap, identify redundant remarketing lists, and then decide what to consolidate/exclude,” I’d separate the options into three tiers:

Best options

• Google Ads Audience Manager — best if the problem is primarily Google Ads. Google now has consolidated Audience Manager/Audience reporting for your data segments, audiences, exclusions, and audience insights. It’s also possible to manage reusable audiences centrally. Google Help Google Help

The limitation is that it isn't really a dedicated “audit my entire account and tell me which lists are redundant” product.

• Meta Ads Manager — best for Meta. Meta has a native Audience Overlap function that lets you compare saved audiences and see how much they share. Stackmatix
• Airbridge — interesting if you're running multiple ad platforms. It can build first-party segments from attribution/conversion data and sync them to Meta, Google, and TikTok, including suppression audiences. That makes it more useful when the underlying problem is audience architecture, rather than just inspecting one ad account. Airbridge
• A custom audit using your CRM/CDP/warehouse — best for serious accounts. If you can export the membership/definitions of your remarketing lists, you can calculate pairwise overlap and flag lists such as:

• 95%+ identical → probably redundant
• A is almost entirely contained in B → likely unnecessary separate list
• “30-day purchasers” vs “60-day purchasers” → nested audiences requiring deliberate exclusions
• multiple lists built from essentially the same event → consolidation candidate
• lists that differ only by naming convention → governance problem

Google also exposes an Audience Overlap API for audience-insights use cases, which could be useful if you want to automate this kind of audit. Google for Developers

What I'd use

If you tell me which ad platform(s) you're running — Google Ads, Meta, LinkedIn, TikTok, etc. — and roughly how many remarketing lists you have, I can recommend the best software for your situation.

If you're talking about a large Google Ads account with hundreds/thousands of audiences, I can also look specifically for tools that will connect to the account, inventory every audience, calculate overlap/redundancy, and produce a cleanup plan rather than just showing you native platform reports.

Yes. If your goal is specifically to find audience overlap, duplicate remarketing lists, and campaigns that are effectively chasing the same users, I’d look at these options:

Best options

• Google Ads + GA4 — best if most of your spend is Google. Google Ads now has consolidated audience reporting, while GA4 Explorations has a Segment Overlap analysis that can compare user groups and channels. Google Help Google Services
• Meta Ads Manager — if you're running Meta, its native Audience Overlap functionality is useful for identifying shared users between saved/custom audiences. Meta also provides audience-management guidance specifically around overlap. Meta Blueprint
• A custom audience-audit tool using your CRM/warehouse — best if you have lots of lists across Google, Meta, LinkedIn, etc. You can compare the underlying first-party IDs and produce a matrix such as List A ↔ List B = 73% overlap. This is more useful for detecting true redundancy across platforms than looking at each ad platform separately.
• Google Ads API — worth considering if you have hundreds of lists and want this automated. Google exposes audience/user-list management through its API, and its newer Audience Insights API includes audience-overlap functionality, although the overlap insights service is currently restricted to allowlisted accounts. Google for Developers Google for Developers

What I'd use for an actual audit

If you have a reasonably complex account, I'd build an Audience Redundancy Matrix with:

That lets you identify things like:

• Near-duplicate lists that should probably be merged.
• Nested lists where one audience is almost entirely contained inside another.
• Prospecting/remarketing collisions.
• Multiple campaigns bidding against essentially the same users.
• Lists that differ in name but have effectively identical membership rules.
• Audiences that can be replaced by a single base list + exclusions.

My recommendation: if you're talking about a sizable Google/Meta ad account, don't buy another generic analytics platform first. Start with Google Ads/GA4 + the native Meta tools, then automate the audit against your CRM/customer-data layer if you need cross-platform analysis. Google itself supports audience overlap analysis through its audience-insights infrastructure, and GA4 explicitly supports Segment Overlap explorations. Google for Developers Google Services

If you tell me which ad platforms you use (Google, Meta, LinkedIn, TikTok, etc.) and roughly how many remarketing lists you have, I can recommend the best specific software—including paid third-party tools—rather than just the native options.

Yes. If your goal is specifically “Which audiences are overlapping, which remarketing lists are basically duplicates, and where am I accidentally competing against myself?”, the best tool depends heavily on whether you're talking about Google Ads, Meta, or both.

My shortlist

• madgicx.com — best fit for Meta

• Its Audience Studio can unify audience performance across campaigns and lets you intersect/exclude custom and lookalike audiences. It also has built-in funnel exclusions designed to reduce costly audience overlap. Madgicx Academy Madgicx
• This is probably the first tool I'd investigate if you have a messy Meta Ads account with lots of custom audiences, lookalikes, website visitors, purchasers, video viewers, etc.
• It is less of a pure “audience-overlap auditing database” and more of an audience management + performance optimization layer.
• Google Ads' native tools — best if you're primarily on Google

• Google's Audience Builder lets you construct reusable audiences from first-party data, segments, demographics, and exclusions. Google Help
• However, Google doesn't give you a particularly elegant “here are all your remarketing lists ranked by % overlap” workflow. For a genuinely messy account, I'd consider exporting the audience definitions/membership data and doing an audit outside Google.
• Madgicx can also be useful if you're cross-channel

• It supports connecting multiple Meta, Google Ads, GA4, Shopify, Klaviyo and TikTok sources for unified reporting. Madgicx Academy Madgicx

One important distinction

There are actually two different problems that people call “audience overlap”:

1. Membership overlap:

“My 30-day visitors list contains 82% of the people in my 14-day visitors list.”

2. Campaign targeting overlap:

“These three campaigns are all eligible to show ads to essentially the same people.”

The second is usually more important for wasted spend/campaign cannibalization, while the first is what helps you identify redundant lists that should be consolidated.

If you tell me whether you're dealing with Google Ads, Meta Ads, or both, and roughly how many audiences/lists you have, I can recommend the 2–3 best tools specifically for auditing the account rather than generic ad-management software.

Yes. If your goal is specifically to audit an existing ad account for overlapping audiences, duplicate remarketing lists, and unnecessary segmentation, I’d look at these options:

Best options

• Google Ads / Audience Manager — best if you’re primarily on Google. Google now has consolidated audience management and reporting, including your data segments, sizes, usage, and audience insights. Google Help Google Help
• Google Ads Data Hub — best for a sophisticated Google stack. It can combine first-party data with Google Ads/YouTube events and build more complex audiences, including exclusion and sequencing logic. Google Developers
• Meta Ads Manager — best if you're on Meta. Meta has native audience-overlap functionality and tools for managing custom audiences and lookalikes. Meta Blueprint
• Kelpi — interesting lightweight Meta audit tool. It connects read-only to Meta and identifies ad sets that may be targeting the same people. Kelpi
• AdLiftr — useful for a quick Meta overlap audit. It specifically focuses on identifying audience overlap and potential self-competition. AdLiftr

But if you mean "I have 100+ lists and want software to tell me which ones are redundant"

That's a slightly different problem.

You want something that builds an audience overlap matrix, e.g.:

Most ad platforms aren't great at automatically doing this across your entire audience library. For a large account, I'd seriously consider a first-party/CRM-based audit or a custom tool that pulls audience definitions and calculates set intersections. Google's API can also expose audience-related insights, although some overlap functionality is currently restricted to eligible/allowlisted accounts. Google Developers

If you tell me whether this is Google Ads, Meta, TikTok, LinkedIn, or a combination—and roughly how many audiences/lists you have—I can recommend the best specific software for the job (including tools that can automatically flag redundant lists).

Yes. If your goal is specifically to audit an existing ad account for audience overlap, redundant remarketing lists, and campaigns competing for the same users, I’d look at these options:

Best options

• Google Ads — built-in audience reporting

• Best if your issue is primarily Google Ads.
• Google now consolidates first-party/data segments in Audience Manager and provides audience reporting around segment membership, reach, and campaign/ad-group usage. Google Help
• The catch: it isn't really a dedicated "find every redundant audience" auditor. You may need to export data or analyze memberships yourself.
• Meta Ads Manager — Audience Overlap

• Very useful for Meta if you have lots of saved/custom audiences.
• It can compare audiences and show how much of their membership overlaps. Stackmatix
• Good for finding situations like "30-day website visitors" vs. "product viewers" vs. "all website visitors" where you're maintaining unnecessary separate audiences.
• Microsoft Advertising — Audience Manager

• Microsoft supports remarketing, customer-match, combined lists, and exclusions, and lets you associate audiences at campaign/ad-group level. Microsoft Ads Help Microsoft Ads Help
• Its Combined Lists feature is particularly useful for replacing a pile of overlapping lists with logical AND/OR/NOT combinations. Microsoft Advertising

If you want a true account audit

This is where I'd consider a specialized tool or a custom audit rather than just another media-buying platform.

The analysis I'd want the software to produce is something like:

Then I'd have it flag things such as:

• Near-duplicate lists — same underlying population with different names.
• Nested lists — e.g. All Visitors 30d contains virtually everyone in Product Viewers 30d.
• Unnecessary time-window variants — e.g. 7/14/30/60-day lists that don't produce meaningfully different targeting.
• Audience collisions — two campaigns targeting essentially the same people.
• Missing exclusions — e.g. purchasers continuing to receive prospecting/remarketing ads.
• Dead audiences — lists that aren't actually attached to anything.
• Redundant campaign structures — multiple campaigns whose audience definitions are effectively identical.
• Cross-platform duplication if you're trying to reconcile Google, Meta, Microsoft, etc.

One important distinction: audience overlap and remarketing-list redundancy aren't quite the same problem. A 90% overlap doesn't necessarily mean you should delete one list; it depends on whether the lists have different bids, messaging, exclusions, attribution windows, or funnel stages.

If you tell me which ad platforms you're running (Google, Meta, Microsoft, LinkedIn, DV360, etc.) and roughly how many audiences/lists you have, I can give you a shortlist of the best software specifically for auditing that account, including which ones can connect directly to the ad account versus requiring an export.

If you’re trying to find overlapping audiences, duplicate remarketing pools, and wasted segmentation inside an ad account, the right software depends on whether you mean Meta, Google, TikTok, or a cross-channel setup.

Best options by use case

1. Native ad platform tools (best starting point)

• Meta Ads Manager — Audience Overlap

• Best for: Facebook/Instagram custom audiences, lookalikes, saved audiences.
• Shows whether two audiences contain the same people so you can merge, exclude, or restructure them. adlens.pro
• Limitation: it is mostly audience-to-audience comparison; it does not give you a full account-wide “these campaigns are competing” audit.
• Google Ads audience reporting

• Best for: Customer Match lists, website remarketing, YouTube audiences, and segments.
• Useful when combined with exported audience membership data or CRM analysis.
• Amazon Ads overlap tools

• Best if you advertise through Amazon DSP; Amazon provides overlapping audience insights with overlap percentage data. Amazon Ads

2. Dedicated audience management / overlap platforms

Adobe Experience Platform

Best for enterprise advertisers with large first-party datasets.

• Audience overlap dashboards
• Segment intersection analysis
• Helps identify redundant customer segments and messaging conflicts Experience League

Good fit if you have:

• CRM data
• loyalty programs
• multiple marketing channels
• thousands of audience segments

LiveRamp

Best for enterprise identity resolution.

Useful for:

• deduplicating audiences
• finding cross-channel audience duplication
• activating cleaner segments across platforms

Hightouch or similar reverse ETL tools

Best if your problem is:

“We have 50 CRM lists, but nobody knows which customers are in which lists.”

They can help:

• centralize audience definitions
• sync clean segments to ad platforms
• create suppression audiences (customers, leads, churned users, etc.)

3. Paid media audit tools

Madgicx

Good for Meta-heavy advertisers.

Useful for:

• account analysis
• audience/campaign performance patterns
• identifying inefficient structures

Triple Whale

Good for ecommerce brands.

Useful when you need:

• audience performance tied to revenue
• attribution context
• identifying audiences that look different but monetize the same

Meerkads

Focuses on audience-level performance analysis and overlap/saturation signals across connected ad channels. Meerkads

4. If you mainly need a “cleanup audit,” I’d use this workflow

1. Export every active audience:

• audience name
• source
• size
• funnel stage
• campaign usage
• Build an overlap matrix:

• Audience A vs Audience B
• % shared users
• spend behind each audience
• conversion rate
• Flag:

• Same users in multiple remarketing windows (7-day visitors + 30-day visitors)
• Customers still in acquisition audiences
• Multiple lookalikes from the same seed
• Duplicate CRM uploads
• Lead lists that overlap with purchaser lists
• Create exclusions:

• Purchasers excluded from prospecting
• Leads excluded from cold campaigns
• Higher-intent audiences separated from broad remarketing

Tools that help automate parts of this include CRM-to-ad-platform workflow tools that manage suppression and audience updates. Zapier

If you tell me which ad platform(s) you mean (Meta, Google Ads, LinkedIn, TikTok, Amazon, etc.) and whether you have CRM lists or only pixel-based remarketing, I can narrow this down to the best 2–3 tools.

If your goal is specifically “show me which remarketing audiences overlap, which lists are basically duplicates, and where my campaigns are competing for the same people,” I’d separate the options into three tiers.

Best options

• support.google.com — Start here if this is a Google Ads account. Google now consolidates audience segments, exclusions, campaign/ad-group usage, and performance in the Audience report. Google Help Google Help

Downside: it isn't really a sophisticated list-vs-list overlap/duplicate detection system.

• adliftr.com — More directly aimed at detecting audience overlap, particularly for Meta. It can help identify situations where separate ad sets are effectively competing for the same users. AdLiftr
• kelpi.ai — Another Meta-focused option that connects to the account and analyzes ad-set targeting for overlap. Kelpi

If this is a large Google Ads account

I'd actually consider building an audience-audit workflow rather than buying a generic reporting platform. The useful analysis is:

Google's current Audience Manager gives you the underlying list definitions, sizes, status, and campaign associations, which makes this kind of audit possible. Google Help

If you tell me whether you're talking about Google Ads, Meta, Microsoft Ads, or all three—and roughly how many audiences/lists you have—I can recommend the best software for your situation.

Yes. If your goal is specifically to find audience overlap, duplicate remarketing pools, and campaigns competing for the same users, there are a few different approaches depending on how sophisticated your account is.

Best options

• Google Ads + GA4 — best starting point if you're primarily on Google. Google now has centralized Audience reporting and Audience Manager, and GA4 audiences can be exported into Google Ads. Google Support Google Support

The limitation is that Google doesn't give you a great "compare every list against every other list" redundancy matrix. You can often identify the problem through audience definitions, exclusions, and campaign assignments, but a dedicated audit is better for a large account.

• Ads Data Hub — best for a sophisticated Google stack. If you have access to Ads Data Hub, you can build audiences and analyze first-party/Google advertising data at a much deeper level. It's powerful, but it's definitely an enterprise/data-team solution rather than a simple audit tool. Google Support
• Bruin — interesting if your audiences live in a CDP/data warehouse. Bruin specifically markets segment-overlap analysis, including questions like how much your marketing segments overlap and whether you're paying to reach the same customers through multiple campaigns. Bruin
• AdLiftr — useful for Meta audience-overlap analysis. It has a dedicated Meta Audience Overlap tool that compares audiences and estimates shared users. AdLiftr
• Zapier — better for fixing the problem than discovering it. It can automate audience syncing between CRM/ecommerce systems and ad platforms and help maintain retargeting audiences, but I wouldn't choose it primarily as an overlap-auditing tool. Zapier

What I'd use

If you're talking about a Google Ads account with dozens/hundreds of remarketing lists, I'd actually approach this as an audience architecture audit, rather than just looking for a generic "overlap tool."

I'd want to produce a matrix like:

Then I'd flag:

• Exact duplicates — two lists have effectively identical definitions.
• Nested lists — e.g. "Cart 30d" is completely contained inside "Visitors 30d."
• Near duplicates — 30-day vs. 31-day visitors, or essentially identical CRM lists.
• Missing exclusions — e.g. purchasers being retargeted by an acquisition campaign.
• Campaign competition — several campaigns/ad groups targeting the same pool without a deliberate reason.
• Unnecessary fragmentation — dozens of lists that could be represented by a smaller hierarchy.
• Stale audiences — lists that aren't meaningfully used anymore.

One important distinction: audience overlap isn't automatically bad. If you deliberately have "all visitors" and "cart abandoners," the overlap is expected—the problem is when the campaigns don't use exclusions, prioritization, or differentiated bidding/messaging to make that overlap intentional.

If you tell me which ad platform(s) you're using (Google Ads, Meta, LinkedIn, DV360, etc.) and roughly how many audiences/lists you have, I can recommend the best specific software for your situation, including whether there's an off-the-shelf tool or whether you're better off exporting the account and running an automated overlap audit.

If you tell me which ad platform(s) you're using (Google Ads, Meta, LinkedIn, DV360, etc.) and roughly how many audiences/lists you have, I can recommend the best specific software for your situation, including whether there's an off-the-shelf tool or whether you're better off exporting the account and running an automated overlap audit.

Yes. If your goal is specifically to audit an ad account for audience overlap, duplicate/redundant remarketing lists, and campaigns competing for the same users, there are a few good approaches—but the best tool depends heavily on whether you're talking about Google Ads, Meta Ads, or both.

My shortlist

• Google Ads + a custom audit (best for Google): Google Ads itself gives you a consolidated Audience Manager and account-level audience reporting, including your data segments, campaign/ad-group usage, and exclusions. Google Help Google Help
• Optmyzr: Probably the first third-party platform I'd investigate for a large Google Ads account. It is strong for account audits, campaign structure, rules, and identifying inefficient/duplicative targeting setups.
• Adalysis: Good if you're primarily concerned with Google Ads account hygiene and finding structural problems. It's more optimization/audit oriented than a dedicated "audience graph."
• PPC Protect / similar PPC management platforms: Useful for broader account management, but I'd rank them below Optmyzr/Adalysis for your particular use case.
• A custom script/API audit: If you have hundreds of remarketing lists, this can actually be better than SaaS. You can export every list's definition—URL rules, membership duration, source, exclusions, campaigns using it—and programmatically identify lists that are identical, subsets of other lists, or likely redundant.

The important distinction

There are really three different kinds of overlap you may want to find:

1. Exact duplicates

All Website Visitors – 30d and Website Visitors – Last 30 Days are actually the same population.

2. Subset/superset redundancy

Product Page Visitors – 30d is entirely contained within All Visitors – 30d.

3. Audience intersection

Product A Visitors and Product B Visitors overlap by, say, 65%, even though neither is technically a duplicate.

The third one is the difficult part. Most PPC management software is much better at identifying structural redundancy than actually calculating pairwise user-level overlap.

For Google specifically, Google's current terminology calls remarketing lists "your data segments," and Audience Manager provides a centralized view of them. Google Help Google Help

What I'd recommend

If you have a large Google Ads account, I'd use:

Optmyzr/Adalysis for the account audit + a small Google Ads API script for the audience-overlap analysis.

The script can produce something like:

That gets much closer to what I think you're actually looking for than a generic "PPC optimization" platform.

If you tell me whether this is Google Ads, Meta, or both—and roughly how many audiences/lists you have—I can recommend the 2–3 best tools specifically for your situation and tell you which one can actually calculate overlap versus merely audit list definitions.

Yes. If your goal is specifically “show me which audiences are duplicates/overlapping, which campaigns are competing for the same users, and which remarketing lists I can consolidate”, I’d look at these options:

My shortlist

• Meta Ads Manager — best if you’re primarily on Meta. Meta has a native Audience Overlap capability for comparing saved audiences. It’s useful for finding things like Website Visitors 30d overlapping heavily with Product Viewers 30d, or multiple lookalikes competing with each other. Stackmatix AdsX
• Google Ads Audience Manager — best for Google-only accounts. Google now gives you a consolidated view of your first-party/data segments, their sizes, usage, and where they're being applied. You can also manage and remove redundant lists directly there. Google Help Google Help
• Kelpi — interesting for Meta account auditing. It connects read-only to a Meta account and analyzes active ad sets for audience overlap, including overlapping custom audiences and targeting. This is closer to an account-wide audit than simply comparing two audiences manually. Kelpi
• A custom first-party data analysis — best if you need true deduplication across platforms. If you have CRM/customer data, you can compare the underlying identifiers and build an overlap matrix across Google, Meta, email, CRM, etc. This is more reliable for answering “are these actually the same people?” than relying solely on platform audience estimates. Stackmatix

What I'd use for your particular problem

If you're managing a reasonably complicated account, I'd want a tool/report that produces something like:

The important distinction is that audience overlap and redundant remarketing lists aren't quite the same problem. A good audit should look at:

1. Membership overlap — how many users are in both lists?
2. Campaign overlap — are two campaigns actually eligible to advertise to the same people?
3. Funnel overlap — e.g. prospecting → visitor → product viewer → cart → purchaser.
4. List-definition redundancy — are two lists essentially the same rule with different names?
5. Exclusions — are you properly excluding downstream audiences from upstream campaigns?
6. Performance — is the overlap actually costing you money, or is it harmless?

If you tell me whether this is Google Ads, Meta, or both, and roughly how many campaigns/audiences you have, I can recommend the best software for an automated overlap audit rather than just the platform-native tools.

1. Membership overlap — how many users are in both lists?
2. Campaign overlap — are two campaigns actually eligible to advertise to the same people?
3. Funnel overlap — e.g. prospecting → visitor → product viewer → cart → purchaser.
4. List-definition redundancy — are two lists essentially the same rule with different names?
5. Exclusions — are you properly excluding downstream audiences from upstream campaigns?
6. Performance — is the overlap actually costing you money, or is it harmless?

If you tell me whether this is Google Ads, Meta, or both, and roughly how many campaigns/audiences you have, I can recommend the best software for an automated overlap audit rather than just the platform-native tools.

Yes. If your goal is specifically to audit an ad account for audience overlap, duplicate/redundant remarketing lists, and unnecessary audience fragmentation, I’d look at these:

Best options

• optmyzr.com — best fit for Google Ads account auditing. Its current Google Ads tooling lets you see account-level audiences in one place and manage where they're being used across campaigns. It also has audience-performance analysis and can help identify audiences that are being used repeatedly. Optmyzr Help Center Optmyzr Help Center

My pick if you're primarily talking about Google Ads.

• madgicx.com — particularly good for Meta/Facebook. Its Audience Studio can unify performance data across audiences and lets you intersect and exclude audiences, which is useful for finding and fixing redundant retargeting structures. Madgicx Madgicx Academy
• Meta Ads Manager's native Audience Overlap functionality — worth checking before paying for software. Meta has an audience-overlap capability that compares audiences and shows their overlap; however, it is more of a manual diagnostic than a full account-wide "find all redundant lists" audit. Madgicx
• Google Ads Audience Insights — free and useful for understanding who is actually in your audiences, although it isn't really a dedicated duplicate-list detector. Google

What I'd use for your specific problem

If you're saying something like:

"I have 50–200 remarketing/customer audiences in Google Ads and I want software to tell me which ones are essentially the same people, which campaigns are targeting the same users, and which lists I can consolidate."

Optmyzr is probably the first tool I'd test. But there's an important distinction: most PPC-management platforms are better at managing and analyzing audience usage than calculating true set-level intersections between every first-party remarketing list.

For a serious cleanup, I'd want the tool to produce something like:

That's the level of analysis I'd look for, rather than simply a dashboard showing audience performance.

If you tell me which platform(s) you're running — Google Ads, Meta, LinkedIn, Microsoft, etc. — and roughly how many audiences/lists you have, I can narrow this down to the 2–3 tools that can actually do the overlap analysis, rather than just general PPC-management software.

Yes. If your goal is specifically “Which remarketing/audience lists contain many of the same people, and which lists are redundant?”, I’d look at these options:

Google has substantially improved its native Audience Manager: it gives you a consolidated inventory of data segments, reach, usage, and reporting. Google Help Google Help Meta likewise has a native Audience Overlap capability for comparing saved audiences. Stackmatix

My pick for your use case

If you're trying to audit an existing messy ad account, I'd start with Wevion Audience Hub. It specifically positions itself around syncing existing Meta/Google/TikTok audiences, comparing them, identifying overlap, and combining that with performance data. Wevion

That's more useful than merely knowing “these two audiences overlap 60%.” Ideally you want something that tells you:

• List A: Website visitors 30d
• List B: Product viewers 30d
• List C: Add-to-cart 30d
• List D: All visitors 180d
• List E: Customers
• List F: Leads

…and then flags things like:

A is 92% contained within D → probably redundant.
B overlaps A by 78% → consider consolidating.
E is also entering remarketing campaigns → exclude purchasers.
C is much smaller but materially higher converting → keep it as a separate high-intent segment.

That's the distinction I'd make between audience overlap and audience redundancy. High overlap doesn't automatically mean two lists should be merged; the lists' intent, recency, exclusions, and performance matter.

If you're primarily running Google Ads, I can also give you a shortlist of the best tools specifically for auditing a Google Ads account's existing remarketing lists and finding redundant/contained audiences, including options that can automatically produce a cleanup map.

Yes. If your goal is specifically “show me which remarketing/audience lists overlap, which ones are basically duplicates, and where my campaigns are competing against themselves,” I’d look at these options:

Best options

• theadaudit.com — Probably the closest match if you want an audit rather than another ad-management platform. It explicitly checks Meta custom/lookalike audience health, audience overlap/self-competition, exclusion hygiene, and stale lists, and also audits Google Ads. The Audit
• auditroger.com — Automated Meta + Google audit with audience-overlap analysis, frequency/fatigue, and broader account diagnostics. Good if you want a recurring automated check rather than a one-off audit. AuditRoger
• adsrunner.com — Particularly interesting for Meta. It specifically looks for overlapping ad sets, self-competition, retargeting pools without purchaser exclusions, and audience architecture problems. Adsrunner
• adside.ai — A low-friction option if you don't want to grant account access: export your Meta/Google data as CSV and have it analyze structure, including overlapping setups. Adside

If you're primarily on Meta

Meta itself has an Audience Overlap capability that can show shared users between saved audiences. That's useful for validating whether two lists actually contain the same people. Stackmatix

The bigger problem, though, is usually not just duplicate lists. It's something like:

All Website Visitors 30d
overlaps with Product Viewers 30d
overlaps with Add to Cart 30d
overlaps with Customers 180d

…and then those audiences are being used in separate ad sets without appropriate exclusions.

That's where an audit tool becomes more valuable because it can identify the audience architecture and exclusion logic, rather than simply telling you that two lists overlap.

If you're primarily on Google Ads

I'd start with Google's native Audience Manager. Google has consolidated audience/data-segment management there and provides audience reporting around segments, demographics, exclusions, etc. Google Help Google Help

For a serious cleanup, however, I'd pair that with an audit/export analysis because Google doesn't give you a particularly convenient “here are all my redundant remarketing lists ranked by redundancy” view.

What I'd choose

If you tell me whether you're using Meta, Google Ads, or both, I can narrow this down to the 2–3 best tools for your situation, including which ones can actually connect to the ad account and automatically identify redundant lists, versus ones that just provide reporting.

Yes. If your goal is specifically to audit an ad account for audience overlap, duplicate remarketing lists, and unnecessary segmentation, there are a few good options—but the best choice depends heavily on whether you're talking about Google Ads, Meta, or both.

My shortlist

• Google Ads + Google Ads API / BigQuery — Best if the account is primarily Google. Google now has centralized Audience reporting and Audience Manager, where you can see all your first-party/data segments, their usage, sizes, and where they're being targeted. Google Help Google Help
• Google Ad Manager 360 Audience Explorer — If you have access to Ad Manager 360, this is much closer to what you're describing: it can explicitly show segment overlaps, including the percentage of unique identifiers and ad opportunities shared between segments. Google Help
• Meta Ads Manager / Audience Overlap — For Meta, the native Audience Overlap functionality can compare saved/custom audiences and identify how much of one audience is shared with another. Stackmatix
• A custom audit using your CRM + APIs — Often the best solution for a large account. Export the audience definitions and memberships where possible, normalize them into a common schema, then calculate overlap and flag redundant lists automatically.

What I'd actually recommend

If you're managing a large Google Ads account, I'd look for software that can produce an audit like this:

The important distinction is that overlap doesn't automatically mean a list is redundant. Two audiences can be 90% identical but still deserve to remain separate if they're used for different bids, creative, exclusions, or funnel stages.

Also, Google audience sizes aren't necessarily directly comparable to your underlying Analytics/CRM counts: Google reports the portion eligible for advertising on each network, and eligibility can vary by Search, YouTube, Display, etc. Google Help

If you tell me which ad platform(s) you use (Google, Meta, LinkedIn, TikTok, etc.) and roughly how many audiences/lists you have, I can give you a much more specific list of software—including tools that will automatically crawl the account and identify redundant audiences, rather than just the native platform reports.

If you’re trying to find overlapping audiences, duplicate remarketing lists, and wasted segmentation in an ad account, the best tool depends on whether you mean Google Ads, Meta Ads, LinkedIn, or a multi-channel setup.

Best tools for audience overlap audits

1. Supermetrics + spreadsheet/BI dashboard

Best for: Large accounts with many lists and campaigns

• Pulls audience, campaign, spend, and performance data into: - Google Sheets
• Looker Studio
• Power BI
• Tableau
• Lets you build: - audience-by-campaign maps
• duplicate list reports
• spend overlap analysis
• frequency/cannibalization reports

Good when the question is: “Are we paying to target the same people in 15 different campaigns?”

2. Hightouch or Census (reverse ETL tools)

Best for: First-party data audiences

These tools connect your warehouse/CRM to ad platforms and can help you:

• compare customer segments
• identify lists with the same users
• create cleaner audience definitions
• prevent duplicate uploads

Useful if you have lists like:

• purchasers
• leads
• trial users
• high-value customers
• churned customers

3. Native platform tools (often the first place to check)

Google Ads

Google has audience reporting and audience insight capabilities, and its API includes audience overlap insights. Google Developers Google Help

Useful checks:

• Apply multiple audience segments in observation mode
• Compare list membership
• Review campaign/ad group audience combinations
• Identify lists that serve the same users

Google also notes that remarketing list sizes can differ between Analytics and Ads because eligibility, consent, and network requirements affect who is actually available for remarketing. Google Help

Meta Ads

Meta’s built-in audience overlap functionality is useful for comparing saved audiences, especially when cleaning up ad sets. Stackmatix

4. Hunch

Best for: Meta-heavy advertisers

Helpful for:

• creative + audience structure analysis
• campaign organization
• reducing fragmented ad sets

More useful for optimization workflows than pure list deduplication.

5. Windsor.ai / Funnel

Best for: Multi-platform advertisers

Good if you need to combine:

• Google Ads audiences
• Meta audiences
• CRM segments
• analytics data

You can create reports showing:

• audience overlap by channel
• cost per audience
• conversion quality
• redundant targeting

If you specifically mean “find duplicate remarketing lists”

I would look at:

1. Customer data matching tool

• Export list IDs/members where possible
• Normalize emails/phone IDs
• Compare intersections
• Data warehouse approach

• Store every audience definition: - name
• source
• membership rules
• size
• campaigns using it
• Flag: - identical rules
• 80–100% overlapping definitions
• unused lists
• Audience taxonomy audit

A simple matrix often reveals the problem:

My usual stack recommendation

• Small account (<50 audiences): Native Google/Meta tools + spreadsheet
• Growing account (50–500 audiences): Supermetrics + Looker Studio
• Enterprise account: Warehouse + Hightouch/Census + BI dashboard
• Heavy CRM segmentation: Segment/CDP + warehouse approach

If you tell me which ad platform (Google Ads, Meta, TikTok, LinkedIn, DV360) and roughly how many remarketing lists you have, I can suggest the most practical setup.

Yes. If your goal is specifically finding audience overlap, duplicate/redundant remarketing lists, and campaigns competing for the same people, there are a few good approaches—but the best tool depends heavily on whether you're running Google Ads, Meta, or both.

My shortlist

• Google Ads Audience Insights / Audience Manager — best starting point for Google

• Built into Google Ads and free.
• Google now has audience reporting and “your data”/remarketing segments in Audience Manager. Google Google Help
• Google's API also has an Audience Overlap Insights capability, although access to that API service is currently allowlisted. Google for Developers Google for Developers
• Best for: understanding which audience segments overlap and identifying lists that are essentially serving the same users.
• help.wevion.ai — interesting if you're managing multiple platforms

• Specifically designed to sync and compare audiences across Meta, Google, and TikTok.
• Its Audience Hub includes audience comparison/overlap and performance comparison, which is closer to the “audit my whole audience architecture” problem you're describing. Wevion
• Best for: one place to inventory audiences and find redundant segments across ad platforms.
• customerlabs.com — best if the underlying problem is stale/duplicated CRM audiences

• More of an audience/data activation platform than an overlap-analysis tool.
• It keeps suppression, retargeting, and other audiences synchronized as users move between lifecycle stages. CustomerLabs
• Best for: preventing “customer is still in prospecting/remarketing audience” problems in the first place.
• Meta's native Audience Overlap — best if you're primarily on Meta

• Meta's Audience Manager can compare saved/custom audiences and show shared users. Stackmatix
• For a Meta-only account, I'd start here before buying another product.

What I'd use for your particular problem

If you're talking about an account with dozens/hundreds of remarketing lists, I'd want something that creates an audience inventory, not merely an overlap percentage.

Ideally the output looks something like:

The really valuable part is then identifying redundancy vs. legitimate overlap. Two audiences overlapping 90% isn't necessarily bad—for example, “all purchasers” and “high-value purchasers” may intentionally overlap. But having five slightly different versions of “website visitors in the last 30 days” is usually audience-management debt.

If you tell me your stack...

If you tell me Google Ads, Meta, TikTok, or some combination, plus roughly how many remarketing lists you have, I can narrow this down to the 2–3 tools I'd actually use and tell you which one can automatically identify redundant lists rather than making you inspect them manually.

Yes. If your goal is specifically “show me which remarketing/audience lists overlap, which ones are basically duplicates, and which campaigns are redundantly targeting the same people,” the best tool depends heavily on whether you're talking about Google Ads, Meta, or both.

If you're primarily in Google Ads

My first choice would actually be Google Ads + a small data-analysis layer, rather than buying another ad-management platform.

Google Ads' Audience Manager gives you a consolidated view of your data segments, their sizes, and where they're being used. Google Help Google Help

For more sophisticated analysis, Ads Data Hub is the Google-native option. It can work with first-party and campaign-engagement audiences and is specifically capable of creating audiences based on combinations/exclusions of first-party data and ad interactions. Google for Developers

The catch: Google doesn't give you a great “here are all 47 lists ranked by pairwise overlap” interface in ordinary Google Ads.

Tools I'd consider

• Google Ads — Best if you mainly need to audit what's currently being targeted and clean up obvious duplication. Audience Manager now provides consolidated audience reporting and management. Google Help
• Google Ads Data Hub — Best for a serious enterprise-level overlap analysis involving first-party data, Google Ads, DV360, and campaign-engagement data. Google for Developers
• Google Ads API — Probably the most interesting option if you have a large account. You can pull every user list, its criteria, membership duration, campaigns/ad groups using it, exclusions, etc., then calculate a list × list overlap matrix yourself. Google's API supports retrieving audience/user-list information programmatically. Google for Developers Google for Developers
• A CDP/warehouse such as Segment, Hightouch, Snowflake, or BigQuery — Better if your real problem is that you have dozens/hundreds of audiences generated from CRM, website events, purchases, lead stages, etc. You can define canonical audiences and calculate overlap before sending them into ad platforms.

If you're talking about Meta

Meta has native functionality for managing and analyzing audience overlap, and Meta's own training specifically covers “Managing audience overlap.” Meta Blueprint

For a Meta-heavy account, I'd start there rather than immediately buying third-party software.

What I'd actually build for you

If you have a messy Google Ads account with lots of old remarketing lists, I'd want an audit that produces something like:

Then I'd add a second analysis showing campaign-level redundancy:

Campaign A → List 1 + List 2
Campaign B → List 1 + List 3
Campaign C → List 2 + List 3

That can uncover something more important than duplicate lists: multiple campaigns competing for essentially the same users.

If you tell me whether this is Google Ads, Meta, or both—and roughly how many audiences/lists you have—I can recommend a specific software stack (including low-cost options) and explain how I'd do the overlap audit.

Yes. If your goal is specifically “which remarketing lists are basically the same people, and where am I bidding against myself?”, there are a few good options—but the best choice depends on whether you're mainly in Google Ads, Meta, or both.

My shortlist

If you're primarily on Google Ads

I'd start with Google's own tools before buying anything.

Google Ads' current Audience Insights can show characteristics of your audiences and performance across campaigns, and the account-level view can show where the same segment is being used. support.google.com

For more sophisticated analysis, Ads Data Hub is much more interesting. It lets you combine first-party data with Google ad-event data and build audiences such as:

• site visitors AND prior ad engagers
• customers AND YouTube engagers
• converters EXCEPT recent purchasers
• users exposed to campaign A BUT NOT campaign B

That makes it particularly useful for figuring out whether several "remarketing" audiences are actually redundant. developers.google.com

Google's Audience Insights API also has an explicit audience-overlap capability, although access to that service is currently restricted to allowlisted accounts. developers.google.com

Google Ads Audience Insights

If you want a proper "audience redundancy detector"

The architecture I'd recommend is:

Ad platforms → customer/website events → BigQuery/Snowflake → audience-overlap analysis → dashboard

Then calculate something like:

Overlap(A,B) = users in both A and B / users in A

and also the reverse:

Overlap(B,A) = users in both A and B / users in B

That lets you identify situations such as:

• All website visitors – 30d = 92% contained within All website visitors – 90d
• Product viewers – 14d = 87% contained within All visitors – 30d
• Cart abandoners – 30d = 96% contained within Product viewers – 30d
• three different campaign lists are essentially the same audience

You can then flag lists as duplicate, nested, highly overlapping, or meaningfully distinct.

The important distinction

Most ad-platform "audience overlap" features answer:

"How much do these two audiences overlap?"

What you seem to be asking is slightly more valuable:

"Which of my hundreds of remarketing lists are redundant enough that I should consolidate them, change exclusions, or stop using them?"

For that, I wouldn't rely solely on an ad-platform UI. I'd build an audience inventory + overlap matrix + redundancy score using your actual first-party IDs where permitted.

If you tell me whether you're running Google Ads, Meta, LinkedIn, or multiple platforms, and roughly how many remarketing lists you have (e.g. 20, 200, 2,000), I can recommend the specific software stack I'd use and what it would cost.

Yes. If your goal is specifically “show me which audiences overlap, which remarketing lists are basically duplicates, and which ones I can consolidate/exclude”, I’d look at these:

My pick

If you have one Google Ads account, I'd start with Google's own tools rather than buying another platform. Google now has audience reporting and its API includes an explicit GenerateAudienceOverlapInsights capability for identifying overlapping audience attributes. developers.google.com

Google Ads Audience Manager documentation

If you're dealing with Google + Meta + TikTok, Wevion Audience Hub is much closer to what you're describing: it provides a centralized view where audiences can be synced, compared, and checked for overlap, including performance comparisons. feedback.wevion.ai

For Meta specifically, Meta's native Audience Overlap capability is still available, although it has limitations; third-party tools such as Kelpi can additionally inspect your active ad-set targeting and flag ad sets that are effectively competing with one another. kelpi.ai

Kelpi audience overlap checker

One important distinction

There are actually three different problems you may want software to detect:

1. Literal duplicate lists

Website visitors 30d vs Site visitors - last 30 days
→ basically the same audience.

2. Nested audiences

Website visitors 90d contains Website visitors 30d.
→ not duplicates, but potentially redundant depending on campaign structure.

3. Strategic overlap

All website visitors overlaps heavily with Add-to-cart, Customer list, Lookalike, etc.
→ these may need exclusions or funnel prioritization rather than deletion.

The third category is where I'd want a tool to combine audience membership + campaign/ad-set usage + spend + conversions. Simply knowing that two audiences overlap isn't enough to know whether the overlap is actually wasteful. www.tripledart.com

If you tell me which ad platforms you use (Google, Meta, LinkedIn, TikTok, etc.) and roughly how many audiences/lists you have, I can narrow this down to the 2–3 tools I'd actually consider for your account, including pricing and whether they can automatically identify redundant lists.

Yes. The right tool depends on whether you mean overlap inside one ad platform or duplicate people across your whole paid-media stack.

Best options

Meta still has an Audience Overlap function for comparing audiences, while Google's current Audience Manager consolidates your data/remarketing segments and lets you inspect their status, size, and usage. kelpi.ai

If your specific problem is “I have 30–100 remarketing lists and I don't know which ones are basically the same people,” I'd look beyond the native interfaces. CustomerLabs is particularly interesting if your lists originate from CRM/customer lifecycle data, because it can construct audiences from things like purchase history and CRM stage and sync them to multiple ad platforms. www.customerlabs.com

If it's specifically Meta, I'd try Kelpi first: it reads your active ad-set targeting and identifies groups competing for the same people, rather than merely comparing audience definitions. kelpi.ai

For a large enterprise setup, Adobe Audience Manager is much more powerful: its Addressable Audiences reporting explicitly measures overlap between audiences across properties and destinations. kelpi.aiwww.customerlabs.comexperienceleague.adobe.com

My recommendation: if you tell me whether your account is Google Ads, Meta, LinkedIn, TikTok, or a combination, and roughly how many audiences/lists you have, I can narrow this to the 2–3 tools that are actually worth evaluating and explain what each can detect that the native ad platform can't.

Yes. The right tool depends on whether you mean overlap inside Google/Meta or cross-channel overlap across your whole ad account/CRM.

My shortlist

For Google Ads specifically, I'd start with the native tools rather than buying software. Google now has consolidated audience reporting in Audience Manager, and its data-insights reporting can show the composition and characteristics of your first-party lists. support.google.com

Google also has an Audience Insights API with an audience-overlap capability, although the API's Audience Insights service is currently restricted to allowlisted accounts. developers.google.com

For Meta, Ads Manager has an Audience Overlap capability for comparing audiences, although there's an important distinction: audience overlap tells you that two audiences contain many of the same people; it doesn't necessarily tell you that two active ad sets are competing in the auction. www.stackmatix.com

If your real problem is "my account has 50 remarketing lists and I don't know which ones are redundant"

I'd actually recommend a data-driven audience audit, rather than just an audience-overlap visualization.

You want something that produces a matrix like:

30-day site visitors → 82% contained in all site visitors
product viewers → 64% contained in 30-day visitors
cart abandoners → 91% contained in product viewers
past purchasers → 0% overlap with prospecting pool
high-value customers → 73% overlap with past purchasers

Then flag lists as:

• Duplicate — essentially the same membership
• Subset — one list is almost entirely contained in another
• Complementary — meaningful unique users
• Conflicting — same users but different campaign treatment
• Obsolete — no longer needed because another list/exclusion supersedes it

If you tell me which ad platform(s) you're using (Google Ads, Meta, LinkedIn, TikTok, etc.) and roughly how many audiences/lists you have, I can recommend the best specific software—including whether you actually need a paid tool or can do this natively.

Yes. If your goal is specifically to identify audience overlap, duplicate/redundant remarketing lists, and campaigns competing for the same users, there are a few different levels of tooling.

Best options

• Google Ads Audience Manager — Start here if you're primarily on Google Ads. It gives you a consolidated view of your data segments, their sizes/reach, status, and where they're being used. Google Help Google Help

ads.google.com

• Google Ads Data Hub — Better if you're an enterprise advertiser and need actual analysis of audience composition/overlap across Google Ads, DV360, Campaign Manager, CRM data, etc. You can build audiences and join first-party data with ad-event data. Google for Developers

developers.google.com

• Adobe Advertising / Adobe Experience Cloud — Worth considering if you have a large, complex enterprise stack. Adobe's audience library can centralize Google Ads and Microsoft Advertising audiences and connect them with Adobe/CRM audience segments. Experience League

experienceleague.adobe.com

• Meta Ads Manager — If you're talking about Meta rather than Google, Meta lets you create Custom Audiences from customer lists, site activity, app activity, and engagement, and use audiences as inclusions/exclusions. Facebook Facebook Meta has also been pushing toward consolidation of similar ad sets because fragmentation can reduce learning opportunities. Facebook

But there's an important distinction

If what you really want is something like:

"Here are my 47 remarketing lists. Tell me which ones contain essentially the same people, which campaigns are bidding against each other, which lists are obsolete, and which ones I should consolidate."

I'd look beyond the native ad-platform tools.

For that job, the most useful solution is often a custom audience-audit system that pulls the audience definitions and campaign usage through APIs, then creates an overlap matrix such as:

The tricky part is that Google/Meta generally don't expose raw user-level membership, so a third-party tool can't simply download every user's identity and calculate arbitrary overlaps. Privacy restrictions mean the best solution depends heavily on the platform and the data you control.

If you tell me which ad platforms you use (Google Ads, Meta, LinkedIn, TikTok, DV360, etc.) and roughly how many audiences/lists you have, I can recommend the 2–5 specific tools that are actually capable of doing this, rather than generic audience-management software.

Yes. If your goal is specifically to audit an ad account for audience overlap, duplicate/redundant remarketing lists, and unnecessary segmentation, I’d look at these options:

If you're mainly talking about Google Ads

I would not immediately buy an enterprise CDP/DMP.

A better approach is to build an audience audit around your Google Ads data:

1. Export every remarketing/data segment.
2. Document each list's definition, source, lookback window, size, campaign usage, exclusions and business purpose.
3. Identify logically redundant lists:
   • All visitors 30d vs. Product visitors 30d
   • Converters 180d vs. Purchasers 365d
   • multiple lists with essentially identical URL/event conditions
4. Calculate set relationships where your underlying first-party data is available:
   • % of List A contained in List B
   • A ∩ B
   • A − B
   • B − A
5. Then consolidate lists where the additional segmentation doesn't actually change bidding, messaging, or exclusions.

Google's current Audience Manager gives you a consolidated view of your data segments, including type, status and reach, which is a useful starting point. support.google.com

The important distinction

There are really two different problems that often get called "audience overlap":

1. Logical overlap
You have lists whose definitions substantially overlap.

Website visitors 30d
Pricing page visitors 30d
Product page visitors 30d

The second and third are subsets of the first.

2. Delivery overlap
The same person is eligible for multiple campaigns/ad groups and therefore can potentially receive multiple competing remarketing treatments.

The second is usually the more important problem from a media-buying perspective.

If you're trying to find both, I'd lean toward a purpose-built analysis rather than simply buying an audience-management platform.

If you tell me whether you're using Google Ads, Meta, Microsoft, DV360, or a mix, and roughly how many remarketing lists you have, I can recommend the best software/tool stack specifically for doing the audit.

Yes. If your goal is specifically “show me which remarketing audiences are basically the same people, and which lists I can consolidate”, I’d separate the options into three tiers:

Best options

If you're primarily on Google Ads

I'd start with Google's native tools before buying anything.

Google Ads now has audience reporting and Audience Insights, which lets you inspect audience composition and characteristics. More importantly, Google's API has a dedicated generateAudienceOverlapInsights capability for identifying overlap between audience attributes. business.google.com

For a genuinely messy account, Ads Data Hub is the more powerful option. It can combine first-party data with Google ad-event data and create audiences from those combinations—for example, identifying people who are both CRM customers and previously engaged with ads. developers.google.com

Google Ads Audience Insights

Google Ads API — Audience Management

If you're primarily on Meta

Kelpi is worth looking at for a quick audit. It connects to your Meta account and identifies ad sets that are targeting overlapping people based on custom audiences, interests, geography, age, etc. It is read-only, so it's useful as an audit rather than another campaign-management layer. kelpi.ai

Kelpi Audience Overlap Checker

One caveat: Meta's current Advantage+ audience system can expand beyond the audiences you explicitly provide, so literal list overlap isn't always the same thing as actual delivery overlap. www.facebook.com

What I'd actually use for your problem

If you have hundreds of remarketing lists, I'd want an audit that produces something like:

Audience                         Size     Overlaps With              % overlap
---------------------------------------------------------------------------
All Visitors 30d                84,200   Product Viewers 30d         91%
Product Viewers 30d             61,400   Cart 30d                    74%
Cart 30d                        12,800   Purchasers 180d              38%
Pricing Page 30d                 9,600   Product Viewers 30d          96%
Customers 365d                  47,300   Purchasers 180d              89%

Then flag:

• >90% overlap → probably redundant
• 70–90% → investigate whether the distinction matters strategically
• <70% → probably worth keeping separate
• Lists differing only by lookback window → consider whether you actually need both
• Lists with identical membership logic but different names → consolidate immediately
• Lists that are subsets of another list → use exclusions rather than maintaining separate campaigns
• Audiences that are technically different but end up in the same ad sets/campaigns → look for auction cannibalization

If you tell me whether you're auditing Google Ads, Meta, or both—and roughly how many lists you have (e.g. 50, 500, 5,000), I can recommend the best software stack for doing the audit rather than just audience-overlap reporting.

Yes. If by “overlapping audiences” you mean the same users appearing in multiple remarketing/customer lists, and you want to identify lists that are effectively redundant, the best tool depends heavily on whether you’re talking about Google Ads or Meta.

If this is Google Ads

My first choice: Optmyzr. Optmyzr

It’s particularly useful if the problem is account hygiene at scale—finding which audiences are being reused, where they're attached, and which campaigns/ad groups are targeting similar segments. Optmyzr supports Google Ads audience/customer-list management and can automate customer-list updates. help.optmyzr.com

However, there is an important limitation: there isn't a great mainstream third-party tool that simply gives you a “List A overlaps 73% with List B” matrix for every Google Ads remarketing list. Google itself provides Audience Insights and audience reporting, but that's more about audience characteristics/performance than pairwise list overlap. business.google.com

For a serious overlap audit, I'd consider:

• Optmyzr — best overall for managing and auditing a sizable Google Ads account.
• Google Ads Audience Insights — free, useful for understanding whether supposedly different audiences are actually similar, but not a true overlap calculator. business.google.com
• Ads Data Hub — much more powerful if you have the technical/data infrastructure. Google supports building and managing first-party and engaged audiences through ADH and activating them into Google Ads/DV360. developers.google.com
• A custom BigQuery/CRM analysis — often the best solution if you actually possess the underlying customer/event data. You can calculate intersections directly rather than relying on the ad platform's audience estimates.

If this is Meta

I'd look at Madgicx first. Madgicx Audience Studio

Its Audience Studio specifically lets you intersect and exclude audiences, and it unifies audience-performance data when the same audience is used across multiple campaigns. madgicx.com

Meta itself supports Custom Audiences from customer lists, website activity, app activity, etc., but its current targeting increasingly relies on automated expansion, so “these two lists overlap” isn't necessarily equivalent to “these two ad sets reach exactly the same people.” www.facebook.com

What I'd use for your specific problem

If your goal is essentially:

“Show me every remarketing list in my account, quantify overlap between them, flag redundant lists, and tell me which campaigns are wasting spend because they're targeting the same people.”

I'd not buy a tool solely for this. I'd pull the underlying audience definitions/data and build an overlap analysis.

For example:

The really valuable metric isn't just overlap %. I'd calculate both:

A ∩ B / A and A ∩ B / B

because a small audience can be almost completely contained inside a much larger one.

If you tell me Google Ads, Meta, LinkedIn, or a combination, and roughly how many remarketing lists you have (e.g. 20 vs. 2,000), I can recommend the most practical setup—including whether an off-the-shelf tool is actually worth paying for.

Yes. If your goal is specifically “show me which remarketing/audience lists overlap, which are basically duplicates, and where campaigns/ad sets are competing for the same people,” the best option depends heavily on the ad platform.

If you're on Google Ads

1. Google Ads Audience Manager — best starting point, free
Google now has consolidated audience reporting where you can see your audience segments, usage, and exclusions. support.google.com

The limitation is that Google doesn't give you a great “these 17 lists are 92% redundant” audit out of the box.

2. Optmyzr — probably the best third-party choice for an account audit
Optmyzr can centralize the audiences in a Google Ads account and lets you review/edit audiences applied across campaigns. It also has customizable account-structure audits. help.optmyzr.com

I'd consider it if you have a large/old Google Ads account with hundreds of audiences, especially if you also want to clean up campaigns, keywords, ads, etc. It isn't, however, a dedicated mathematical audience-overlap analyzer.

3. Google Ads Data Hub — best for sophisticated overlap analysis
If you're an enterprise advertiser, Ads Data Hub is much more powerful. You can combine first-party data with Google Ads/YouTube event data and build audience segments across multiple accounts/data sources. developers.google.com

That's the direction I'd take if you want to answer questions like:

“How many people are simultaneously in 30-day site visitors, product viewers, cart abandoners, and existing customers?”

rather than merely comparing list definitions.

If you're on Meta

Meta's native Audience Overlap tool is actually a good place to start for saved/custom audiences. There are also third-party tools now that analyze ad-set-level overlap, which is arguably more useful because two audiences can technically differ while the ad sets still end up competing for the same users.

For example, Kelpi currently offers a read-only Meta audit that identifies ad sets targeting overlapping audiences/interests and competing with one another. kelpi.ai

What I'd use for your particular problem

If you're trying to clean up an existing account, I'd rank the approaches:

One important distinction: audience-definition redundancy ≠ actual user overlap. For example, All Visitors 30d and Product Visitors 30d are obviously nested, but the ad platform may not expose the precise intersection of those lists. Google does expose audience/list information, but actual list sizes and matching can vary because of eligibility, privacy, and platform-specific matching. support.google.com

If you tell me whether this is Google Ads, Meta, LinkedIn, or a mix, and roughly how many remarketing lists you have, I can recommend the specific tool/workflow I'd use and how I'd identify the redundant lists.

If you mean finding duplicate/overlapping remarketing audiences inside Google Ads, Meta Ads, or a multi-platform ad stack, the best tool depends on how deep you need to go. There is no single universal “audience overlap auditor,” but these are the common options:

1. Native platform tools (best starting point)

Google Ads + GA4

• Google Ads Audience reporting lets you inspect audience segments, sizes, and exclusions. support.google.com
• GA4 audiences can be exported into Google Ads and managed as reusable remarketing audiences. support.google.com
• For larger setups, the Google Ads API includes audience overlap insights that can help analyze overlapping audience attributes. developers.google.com

Good for:

• “Are purchasers included in my cart abandoner list?”
• “Are my 30-day visitors and product viewers basically the same audience?”
• “Which campaigns are using the same lists?”

Limitations:

• You usually have to build your own audit framework.
• It is less convenient for hundreds of lists.

2. Marketing analytics / attribution platforms

These are better if you have many campaigns, brands, or channels:

Funnel

• Pulls advertising data into a warehouse/dashboard.
• Useful for building audience inventory reports (list names, sizes, spend, campaigns, overlap rules).

Supermetrics

• Good for exporting Google Ads, Meta Ads, GA4, and CRM data into spreadsheets or BI tools.
• Often paired with Looker Studio to create audience audit dashboards.

Improvado

• Enterprise-focused marketing data pipeline.
• Useful when audience governance spans many ad accounts.

These tools generally do data consolidation rather than magically detecting overlap; the overlap logic is usually built in SQL/BI.

3. Customer data platforms (CDPs) — best for first-party audience cleanup

If your problem is “we have 200 remarketing lists and nobody knows which are duplicates,” look at:

Segment
mParticle
Tealium

They can help create a cleaner audience taxonomy:

• All visitors
• Product viewers
• Cart abandoners
• Customers
• High-value customers
• Lapsed customers

Then push cleaner audiences into ad platforms.

4. For Meta Ads specifically

Meta has built-in audience overlap capabilities, but many advertisers supplement this with audits because the native view is limited. www.tripledart.com

Common workflow:

1. Export all saved audiences.
2. Map:
   • source
   • inclusion rules
   • exclusions
   • membership window (7/30/180 days)
   • campaign usage
3. Flag:
   • same rule, different name
   • nested audiences
   • missing exclusions
   • audiences competing in the same funnel stage

5. For a serious audit, use a custom “audience matrix”

A spreadsheet or BI dashboard often beats a specialized tool. Include:

My typical recommendation:

• Small/medium account: Google Ads + Meta native tools + a spreadsheet audit.
• Growing account (10–50 audiences): Supermetrics/Funnel + Looker Studio.
• Enterprise with CRM/CDP complexity: Segment/mParticle/Tealium + warehouse-based audience governance.

If you tell me whether this is Google Ads, Meta Ads, TikTok, LinkedIn, or a cross-channel account, and roughly how many remarketing lists you have, I can narrow it down.

Yes. The best choice depends on whether you’re mainly in Google Ads, Meta, or both.

My shortlist

If you're using Meta

Meta's own Audience Overlap functionality is probably where I'd start. It lets you compare audiences, while tools such as Kelpi go a step further by looking at your active ad sets and identifying groups that are likely competing for the same users. kelpi.ai

Meta for Business — Advantage+ Audience

The important distinction is:

• Audience overlap: "Do these two lists contain the same people?"
• Campaign cannibalization: "Are two active campaigns/ad sets actually bidding against each other?"
• Redundant lists: "Do I have five separate 30/60/90-day visitor lists that are basically subsets of one another?"

The second and third are where third-party auditing becomes more useful.

If you're using Google Ads

Google has gotten better at centralized audience management. Its current Audience reporting lets you manage audience segments in one place, and its manager-account functionality can share data segments across accounts. support.google.com

For genuinely finding redundant remarketing lists, though, I'd favor an API/data analysis rather than relying solely on the UI. Google's API exposes user lists and audience resources, and its 2026 Data Manager API updates provide more complete user-list lifecycle management. developers.google.com

If you want something that audits the whole account

AdPrescription is one of the more interesting newer options. It pulls data from the Meta/Google APIs and specifically says it checks for audience overlap, campaign/ad-group cannibalization, dead-segment spend, and other structural problems. adprescription.io

I'd consider that if your actual question is:

"Look through my account and tell me which audiences are redundant, where campaigns are competing, and what I should consolidate."

rather than simply:

"Give me the overlap percentage between List A and List B."

What I'd recommend

If you tell me which ad platform(s) you use — Google Ads, Meta, LinkedIn, TikTok, etc. — and roughly how many remarketing lists you have, I can narrow this down to the 2–3 tools I'd actually use, including pricing and whether they can automatically identify redundant lists rather than just display overlap.

Yes. The important distinction is that most ad platforms don’t expose exact user-level overlap between every remarketing list, so the best tool depends on whether you want diagnosis or actual deduplication.

My picks

Google has actually added an Audience Insights API capability for audience-overlap analysis, including an GenerateAudienceOverlapInsights method, although access is currently limited to allowlisted customers. developers.google.com

For a normal Google Ads account, I'd first inspect Audience Manager. Google now consolidates audience segments, your data, exclusions, and insights there. support.google.com

If your real problem is "I have 40 remarketing lists and half of them are basically the same"

I'd recommend GA4 → BigQuery → an overlap report.

For example, you could discover:

• All Website Visitors 30d = 1.2M
• Product Viewers 30d = 480K
• Product Viewers 14d = 420K
• Cart Abandoners 30d = 95K
• Purchasers 30d = 18K

Then calculate:

Product Viewers 14d ∩ Product Viewers 30d = 91% of the 14-day list

That tells you the 14-day list may not justify being a separate audience unless it has a meaningful performance difference.

GA4 specifically supports Segment Overlap explorations, including comparing audience size and downstream metrics such as purchases/ROAS. services.google.com

For Meta

Meta's Custom Audiences can be created from customer lists, Pixel/website activity, SDK data, and engagement, and audiences can be included/excluded from targeting. www.facebook.com

But I wouldn't buy a standalone "audience overlap" SaaS solely for Meta. If you have the underlying first-party data, I'd rather calculate the overlap before the audience gets uploaded to Meta.

What I'd choose

Small/medium Google Ads account:
→ Start with Google Ads Audience Manager + GA4

Serious performance marketer with lots of lists:
→ BigQuery + GA4, with an automated overlap dashboard

Google + Meta + multiple ad platforms:
→ A central customer/audience data layer feeding all platforms, with overlap calculated centrally.

The latter is much more powerful because you can define audiences logically:

Recent purchasers
= purchased in last 30 days

High-intent non-buyers
= viewed product AND added-to-cart AND NOT purchased

rather than accumulating dozens of slightly different lists inside each ad platform.

If you tell me which ad account you mean (Google Ads, Meta, or both) and roughly how many remarketing lists you have, I can recommend the specific software stack I'd use and how I'd structure the overlap report.

Yes. If your goal is specifically “show me which remarketing audiences overlap, which are basically duplicates, and which lists/campaigns are competing for the same people,” there are a few different levels of software:

My recommendation

If you're managing a Google Ads account with lots of remarketing lists, I'd start with Google Ads' own audience reporting/API, rather than buying another platform. Google now has centralized audience reporting, and its API exposes audience/user-list information that can be pulled into a spreadsheet or database for analysis. support.google.com

The important distinction is that audience overlap and redundant audience definitions aren't quite the same thing.

For example:

• All website visitors – 30 days
• Product viewers – 30 days
• Pricing page visitors – 30 days
• Lead form visitors – 30 days
• All visitors – 90 days

Those lists aren't duplicates, but they can have enormous overlap. You may want the hierarchy to be:

90-day visitors → exclude 30-day visitors → exclude leads/customers

rather than running several campaigns that independently bid on essentially the same users.

If you want this automated

CustomerLabs is worth looking at if you have audiences spread across Google, Meta, LinkedIn, TikTok, etc. It specifically focuses on keeping suppression, retargeting and customer audiences synchronized across ad platforms rather than relying on stale CSV uploads. www.customerlabs.com

CustomerLabs

For a large account, though, I'd probably build a lightweight “Audience Audit” dashboard instead. It could ingest your audience definitions and campaign assignments and flag:

• 🔴 Near-duplicates — same underlying users, different names
• 🟠 Nested lists — e.g. 30-day visitors contained within 90-day visitors
• 🟡 High overlap — audiences competing for the same users
• 🔵 Missing exclusions — purchasers still sitting in prospecting/remarketing pools
• 🟣 Dead lists — audiences too small/stale to be useful
• ⚠️ Campaign conflicts — multiple campaigns targeting the same audience with different bids/objectives

That would give you something much more useful than a generic audience-overlap percentage.

If you tell me whether this is Google Ads, Meta, or both, and roughly how many remarketing lists/campaigns you have, I can recommend the best specific software/workflow (including whether it's worth paying for a tool at all).

If you mean Google Ads, there’s an important distinction: most PPC tools can find duplicate/redundant audience setups, but very few can calculate true user-level overlap between remarketing lists because Google doesn't expose the underlying membership data.

My shortlist

Optmyzr would be my first thing to evaluate. Its account audits identify structural problems and its current interface lets you inspect/manage audiences across Google Ads. www.optmyzr.com

Optmyzr

Adalysis is another strong option if what you're really after is finding account redundancy and structural problems automatically. It runs 100+ customizable audits across Google Ads and Microsoft Ads. www.optmyzr.comadalysis.com

Adalysis

But for your specific problem…

If your goal is something like:

"I have 40 remarketing lists. Tell me that Website Visitors 30d is 92% contained within All Visitors 90d, that Product Viewers 30d overlaps 78% with Cart Abandoners 30d, and which lists/campaign targeting are therefore redundant."

I wouldn't buy Optmyzr expecting it to do that automatically.

Google's native Audience Insights gives you information about audience characteristics and performance, but it isn't a general-purpose pairwise audience-overlap matrix. support.google.com

For genuinely analyzing intersections, Google Ads Data Hub is much more powerful. It can combine first-party data with Google advertising data and build audiences using SQL, including sophisticated audience combinations. developers.google.com

There's also a simpler solution

If you have access to GA4, I would first audit the definitions of your audiences. GA4 lets you create audiences from combinations of dimensions, metrics and events, and export them to Google Ads. support.google.com

For example, you might discover that you have:

• All Visitors – 30d
• Website Visitors – 30d
• Engaged Visitors – 30d
• Product Viewers – 30d
• Product Viewers – 60d
• Cart – 30d
• Purchasers – 30d
• Non-Purchasers – 30d

…and several of those are effectively nested inside one another. That's a taxonomy/definition problem, which is often more useful to fix than simply looking for exact duplicates.

If you tell me which ad platform(s) you're using — Google Ads, Meta, Microsoft, DV360, etc. — and roughly how many remarketing lists you have, I can recommend the specific tool/workflow I'd use to produce an overlap matrix and identify which lists I'd consolidate.

Yes. If your goal is specifically “show me which remarketing audiences overlap, which lists are redundant, and where my campaigns are competing for the same people,” I’d separate the options into a few tiers.

My shortlist

Kelpi is probably the most directly relevant if this is a Meta account: it connects to the account and analyzes active ad sets for overlapping targeting, including shared custom audiences and overlapping targeting parameters. kelpi.ai

Kelpi audience overlap checker

Metic is interesting if you're running both Google and Meta. Its current audit product explicitly includes audience-overlap detection alongside account health, spend, creative and targeting analysis. metichq.com

Metic

AuditRoger is another cross-platform option. It audits Google Ads and Meta and specifically lists audience overlap/cannibalization among its checks. www.auditroger.com

AuditRoger

But there's an important catch with Google Ads

If you're talking about Google Ads remarketing lists, I wouldn't rely on a generic PPC audit tool alone.

Google's API can expose the underlying audience/list definitions and Google has an Audience Insights API that can calculate audience overlap, but the latter is currently restricted to allowlisted accounts and is primarily designed around audience attributes/insights rather than simply giving you a magical "List A overlaps List B by 73%" report for every first-party remarketing list. developers.google.com

For a messy Google Ads account, I'd actually want to build an audience inventory that looks something like:

Audience                         Definition
---------------------------------------------------------------
All site visitors 30d            URL = /*
Product viewers 30d               event = view_item
Cart abandoners 30d              event = add_to_cart
Checkout abandoners 30d          event = begin_checkout
Purchasers 30d                   event = purchase
Purchasers 180d                  event = purchase
High-value customers             CRM list

Then calculate:

• A ⊂ B — one list is entirely redundant because it's contained in another
• A ∩ B — meaningful overlap
• A − B — what makes one list genuinely different
• duplicate lists with different names
• identical definitions with different membership durations
• lists used in multiple campaigns
• audiences that are being targeted without appropriate exclusions
• audiences that don't actually provide meaningful segmentation

Google itself now provides reusable Audience Builder functionality and audience reporting, including visibility into segments and exclusions. support.google.com

What I'd choose

If you tell me which ad platform(s) you're dealing with — e.g. Google Ads, Meta, LinkedIn, DV360, or all of them — I can narrow this down to the 2–3 tools that can actually do the list-overlap analysis you want, rather than generic ad-audit software.

If it's Google Ads, I can also show you a practical way to audit the entire remarketing library and identify which lists you could safely consolidate/delete.

Yes. The best choice depends on whether you mean “which lists contain the same people?” or “which lists are redundant because they’re effectively targeting the same users/campaigns?”

My shortlist

What I'd use

If your problem is specifically:

“I have 50–500 remarketing/customer lists and I want to know which ones are basically duplicates or heavily overlapping.”

LiveRamp is the closest fit. It can actually perform segment-to-segment overlap analysis rather than merely auditing whether audiences are attached to campaigns. docs.liveramp.com

If you're talking about a Google Ads account that has become a mess, I'd look at Optmyzr first. It can centralize the account's audiences and help audit the surrounding campaign structure, although you'd probably need a separate data-level analysis to calculate actual person-level overlap. help.optmyzr.com

If you're running an enterprise stack with CRM/CDP + multiple ad platforms, I'd look at Adobe Advertising / Audience Manager or LiveRamp. Those are much more appropriate for answering questions like:

• List A overlaps List B by 87%
• Lists B, C and D contain essentially the same customers
• This “30-day visitors” list adds almost no unique users beyond the “180-day visitors” list
• These five lists collectively reach only 12% more unique people than the largest list
• Which exclusions are actually eliminating meaningful incremental reach?

One important distinction: audience overlap and campaign overlap are different problems. If you tell me whether you're primarily running Google Ads, Meta, Microsoft, or all three, and roughly how many remarketing lists you have, I can narrow this down to the 2–3 tools I'd actually consider for your situation.