Have you ever been in a situation where you’re running multiple ad sets at the same time, but the results are not what you expected, even though the budget is being spent? Your adsets are likely targeting the same group of customers, causing your ads to “compete” with each other and drive up costs. This is the problem of Audience Overlap in Facebook advertising, a factor that is often overlooked but directly affects campaign effectiveness and profitability. In this article, Optimal will guide you on how to see audience overlap Facebook ads and how to handle it to optimize your budget and increase your conversion rate.
What Is Audience Overlap?
When running ads on Facebook, one of the issues that we and many advertisers frequently encounter is Audience Overlap—the phenomenon of audience duplication. Simply put, this is a situation where multiple adsets target the same audience or similar audiences, causing your own ads to “compete” with each other in the Meta Ads auction. Imagine it like this:
- You have Audience 1 with X number of people.
- You have Audience 2 with Y number of people.
In reality, there will be a group of users who overlap between these two audiences – we call this Audience Overlap. This means these users appear in both of your targeting lists simultaneously. The problem arises when we run ads for both audiences at the same time. Let’s say Audience 1 has a 30% overlap with Audience 2, meaning 30% of the people in Audience 1 are also in Audience 2. If you run two campaigns:
- Campaign 1 targets Audience 1.
- Campaign 2 targets Audience 2.
Both campaigns will show ads to this overlapping group of 30% of users. The consequences are:
- The budget is spent repeatedly.
- Reporting results are skewed.
- Ad costs are inflated.
This is why Audience Overlap is considered one of the “invisible traps” of Facebook advertising that you—the advertisers—need to understand and address from the beginning to avoid wasting your budget.
Negative impacts of Audience Overlap in Facebook Ads
When advertisers deploy multiple adsets within the same campaign, Audience Overlap is a common situation. However, this has many significant negative impacts on ad effectiveness. We will analyze these in detail below so you can clearly see the extent of the influence.
Increased costs
One of the most apparent consequences of Audience Overlap is inflated ad costs. When two or more adsets target the same group of customers, they end up competing with themselves in the Facebook auction.
For example, adset A initially bids at $5, but to win the auction, the system raises its bid to $7. Meanwhile, adset B, which was already bidding at $7, has to increase to $10 to compete. The result is an unnecessary increase in ad costs, while the business receives no real value from this competition.
Causes Ad fatigue in users due to ad repetition
When audiences overlap, users will repeatedly see similar or even identical ads from the same brand. This phenomenon leads to ad fatigue—viewers feel bored, annoyed, and even repulsed by the ads.
The consequence is less engagement, which drives down the CTR (Click-through rate), increases the CPM (Cost per thousand impressions), and ultimately significantly decreases ad effectiveness. For us, this is a very dangerous sign because it not only reduces current performance but also has a long-term impact on brand perception in the eyes of customers.
Limited delivery effectiveness
In addition to costs and user experience, Audience Overlap also limits the ability to optimize and deliver ads. Facebook has a hard time determining which ad set should be prioritized for delivery, leading to the budget being scattered and not focused on the most potential customer groups. The result is:
- Fewer orders.
- Slower and less effective optimization.
- The overall performance of the campaign declines.
In other words, by allowing audiences to overlap, we are tying our own hands in terms of getting the most out of the power of the Facebook ad delivery system. To run your campaigns effectively, you can consider using Optimal Agency’s services.
With over 11 years of experience in the Digital Marketing field, Optimal Agency has directly implemented and managed many real-world projects across a variety of industries. Throughout our operations, we have partnered with thousands of domestic and international businesses, from small to large scale, helping them effectively launch online ad campaigns on various channels. As a result, many clients have made significant progress in reaching users and growing their sales.
As an official partner of major platforms such as Facebook, Google, and TikTok, we own a rich and high-quality system of advertising resources, professionally built and optimized. Optimal Agency provides reliable ad account rental solutions on a variety of platforms: Facebook, Google, TikTok, Bing, Instagram, and more. With our continuous effort, we are always committed to providing the best service, helping businesses optimize costs, increase conversion rates, and boost revenue and profit.
3 How to see audience overlap in Facebook ads
Audience Overlap is one of the causes of increased ad costs and decreased delivery effectiveness. Therefore, advertisers need to know how to see audience overlap in Facebook ads to make optimal decisions. Below are 3 common methods we often use.
Method 1: Check Directly in the Audiences Section
This is the fastest and most accurate method, using a direct tool in Ads Manager.
- Go to All Tools -> select Audiences.
- Select two or more audience lists to compare. For example: “Engaged with Page 30 days” and “Visited website 90 days.”
- Click the three dots icon -> select Show Audience Overlap.
Suppose you have:
- The “Visited website 90 days” audience: 120,000 people.
- The “Engaged with Page 30 days” audience: 80,000 people.
- When comparing, Facebook reports a 40% overlap, meaning about 48,000 people are in both audiences.
If you run two adsets targeting these two audiences simultaneously, nearly half of the users will see the ads repeatedly, which leads to waste.
Method 2: Use Ads Reporting to detect overlap
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In many cases, Facebook doesn’t allow you to check for overlap with small audiences (<1,000 people). In that situation, you can use Ads Reporting to analyze it.
- Create a report with data columns like Reach, Frequency, and Unique Link Clicks.
- If you see an unusually high increase in average frequency (e.g., from 2.5 → 5.0) while reach isn’t expanding, it’s highly likely that the adset has an audience overlap.
A real-world example:
- Ad set A: Reach 50,000, Frequency 2.8
- Ad set B: Reach 55,000, Frequency 3.1
- When the entire campaign is combined, the total reach is only about 70,000 (not 105,000 as expected) -> proving that the 2 adsets overlap by about 35,000 people.
Method 3: Combine Audience Insights to evaluate behavior
Audience Insights is a tool that helps you conduct a deeper analysis of the demographic characteristics and behavior of each audience. When comparing two different audiences, if the demographic and interest information has too high a degree of similarity, the likelihood of overlap is also high. For example:
- Audience A (Lookalike of customers who made a purchase): 100,000 people, of which 60% are women aged 25–34, interested in fashion.
- Audience B (Interest: Fashion, beauty): 150,000 people, of which 58% are women aged 25–34, interested in fashion.
When you run ads, there is a high probability that more than 50% of the people in the two audiences will overlap, causing the ads to compete with each other.
Methods to avoid Audience Overlap when running Facebook Ads
When launching ad campaigns on Facebook, Audience Overlap can cause costs to increase and effectiveness to decrease. To mitigate this issue, advertisers need to apply some specific solutions.
Combine similar ad sets
When you have multiple adsets targeting the same audience, you should combine them into a single adset to prevent them from competing with each other in the auction. This consolidation not only helps optimize delivery effectiveness but also allows for a more focused budget allocation instead of splitting it up and reducing the power of each adset. Also, when you combine adsets, you can more easily manage data and optimize your campaign.
Use exclusion to exclude audiences
One of the most effective ways to reduce overlap is to use the Exclusion feature. Especially in retargeting campaigns, you should exclude people who have already seen or been targeted before. This helps prevent adsets from stepping on each other’s toes and also creates a more reasonable ad experience for users, preventing them from constantly seeing ads from the same brand.
Clear targeting and audience segmentation
Accurate audience segmentation is key to avoiding Audience Overlap. Advertisers should break down audiences by demographic factors, interests, behaviors, or level of engagement. When each adset is designed to target a specific segment, the risk of overlap will be significantly reduced. This approach also makes the campaign clearer and delivers a personalized message that is relevant to each customer group.
Plan and optimize before launch
Before starting a campaign, clearly define your target audience and plan a reasonable budget allocation. Additionally, regularly checking with the Audience Overlap tool in Facebook Ads Manager will help you quickly detect overlapping audiences. By combining this with the Exclusion feature, you can quickly adjust your campaign, ensuring that your ads are always delivered effectively and avoiding wasted costs.
Regularly checking and analyzing Audience Overlap in Facebook ads is a crucial step that helps advertisers optimize costs, avoid wasted budgets, and increase campaign effectiveness. When you understand your overlap status, you can adjust your targeting, combine adsets, or use Exclusion appropriately to ensure your ads reach the most potential customers. This is the key to maintaining sustainable performance and growing revenue from Facebook Ads.
Frequently Asked Questions
Ad auction overlap occurs when you create ad sets with overlapping audiences, causing multiple ads from your Facebook Page to enter the same auction.
Facebook’s system will choose the ad with the highest total value to compete in the auction. The other ads from your Page will not be considered. This can lead to ad sets not spending their full budget or not getting enough results to exit the learning phase. If an ad remains in the learning phase for too long, its performance will be less stable, and the cost per action (CPA) is often higher.
In addition to using the Facebook Audience Overlap tool to manually check for duplicate audiences in your ad sets, you can apply the following strategies to minimize ad audience overlap.
Method 1: Manual Exclusion
Use the Facebook Audience Overlap tool to find overlapping audiences and manually exclude them when targeting your audience within an ad set. For example, you can select a target audience based on interests and behaviors, then separate the audience into more specific interest groups. When you compare these groups, ensure the overlap rate is less than 20%.
Method 2: Use Exclusions in Facebook Ads Manager
You can use the exclusion feature in Facebook Ads Manager. Create a new audience that excludes the characteristics of a previously created audience. For example, if you create one audience based on specific customer profile descriptors, you can then create a new audience and exclude the terms used to describe the first one.
Method 3: Create and Exclude Custom Audiences
This method involves creating custom audiences and then excluding them. For example, you can create a custom audience of people who have watched a specific video. Then, during the ad setup process, you can exclude this audience from a new campaign. This is particularly effective for preventing retargeting campaigns from competing with one another.
