How to Use Facebook’s Lookalike Audiences to Scale Your Campaigns

April 16, 2018

Lookalike audiences are the Facebook feature when it comes to audience targeting. If you’re looking to scale your campaigns and more, it’s a must-consider option.

The Basics: What Is It and How Does It Work?


You can use lookalike targeting to find similar users to your core audience based on interests, click behavior, and conversion habits. The smaller the percentage of your core audience, the more similar your lookalike audience will be.

A lookalike percentage says, “Give me x% of the selected country users who are most similar to my seed audience.” For example, if you create a 1% lookalike in the US, the output will always be around 2.1 million profiles, since this is more or less 1% of the total number of Facebook users in the US.

However, depending on the seed audience, the profiles may greatly differ—for example, a 1% lookalike of your most valuable lifetime users will be different from a 1% lookalike of all website visitors. Therefore, seed quality is the most important factor for success.

You have several options from which to generate lookalike audiences:

  • Your custom audience (email lists, phone numbers, etc.)
  • Website Custom Audience
  • Page fans
  • Campaign data (API-only feature)


A Few Size Guidelines


When segmenting/choosing seed audiences, think quality over quantity. Although quality can be subjective, there are a few generic size benchmarks (guidelines) for your seed audience.

  • Keep it under 50,000, since anything above this may see a drop in performance.
  • Keep it above 1,000.


For example, let’s take our previous 1% US lookalike. Our audience has 2.1 million people. When we create our lookalike audience, Facebook compares the people in this audience against how similar they are to our seed audience of less than 50,000. In other words, we’re magnifying the seed 40 times. If the seed isn’t high quality, then the magnification won’t produce the best audience.

As you can see, you have a lot of choices to test different audience types and associated performance. The key challenge is to segment and structure the audiences to avoid overlaps and achieve the best delivery.

Something to note: Since frequency caps limit the daily number of times you can deliver an ad to a user, lookalike audiences won’t increase your overall reach. And, you’ll have less predictability when it comes to which ad wins each auction.

There’s a way to overcome these challenges, however. Make sure your strategy includes nested lookalikes and smart exclusions. Let’s go into more detail.

Using Nested Lookalikes and Smart Exclusions


Let’s start with an example, where we exclude the next-highest percentage audience from our targeted lookalike audience. So, if you’re targeting lookalike 3% and lookalike 5%, then exclude the 3% audience from the campaign that’s targeting the 5% one.

Nested lookalikes:



Smart exclusions:



With smart exclusions, we exclude the targeted audiences that we’re already using in other live campaigns. For example, if you’re running campaigns with 1% lookalike and 3% lookalike and want to launch a broader targeting campaign, then exclude the 3% lookalike.

Avoiding Campaign Redundancies and Fine-Tuning


When you’re planning your targeting strategy, make sure you’re segmenting your lookalike thresholds according to the value of the user, and excluding the targeted audiences from campaigns to avoid overlap. This’ll allow you to use lookalike audiences from different sources, increasing the overall reach and scalability of your campaigns.

For example, if you’re running a retargeting campaign based on a Website Custom Audience of all your site visitors, exclude this campaign from all of your acquisition initiatives, along with the associated lookalike audiences.

Here’s another scenario. Suppose you’re a travel website and the user funnel includes two conversions—registration and booking. You would segment the audiences based on your goals—perhaps based on the custom audience of the previous month's bookers, conversion pixel data, and Website Custom Audience of people who registered but didn’t book. Your segmentation would look like this:

Custom audience segmentation:



You can use all of these audiences for your acquisition campaigns, along with interest-based and other targeting options.

Here’s the final campaign planning structure for this example. This takes into account that retargeting campaigns are running based on your Website Custom Audiences.

Fine-tuned campaign planning structure:


Putting It All Together


Creating effective lookalike audiences takes a bit of cunning and patience, but it’s not rocket science. With continued practice, refinement, and measurement, you can scale your campaigns to ensure you’re targeting audiences with the most relevant ads at the most relevant time, in a way that works the best for your business. If you haven’t yet implemented this feature, we strongly recommend you get started today!

Jana Christoviciute

Marin Software
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