ChatGPT answers, unedited

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.