A lookalike audience is a group of people who share characteristics with an audience you already have, built so your ads can reach new people instead of existing customers. In Meta ads, you give Meta a source, such as your best customers, and Meta finds people who resemble it.
Meta describes a lookalike audience as "a way your ads can reach new people who are likely to be interested in your business because they share similar characteristics to your existing customers."
How a lookalike audience is built
- Pick a source. The source is a custom audience, usually made from your own customer data. This is your first-party data, and the quality of the source decides the quality of the result.
- Choose where to look. You set the country or countries where Meta should find similar people.
- Choose the audience size. You set a percentage, and Meta fills it with people who look most like the source.
- Use it in an ad set. You target the new audience like any other, and you can compare it against other audiences in the same campaign.
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Meta says that "smaller percentages more closely match your source audience, but larger percentages create a bigger, broader audience." It is a trade between precision and reach.
| Choice | What you get | Fits |
|---|---|---|
| Smaller percentage | A tighter, more similar audience | Accounts with a strong source and a small budget |
| Larger percentage | More people, less similarity | Bigger budgets, or when a small audience wears out fast |
Neither is better in general. A small audience can run out of fresh people and push up frequency, while a very large one drifts away from your best customers.
Choosing a good source
- Use customers who matter most. A list of your highest-value buyers teaches Meta more than a list of everyone who ever clicked.
- Keep it current. A source built from last year's buyers describes last year's customer.
- Match the goal. If you want purchases, build from purchasers, not page visitors.
- Use enough data. A source with only a few people gives Meta little to learn from, so add more customers or combine sources before building.
Lookalikes next to other audience types
A lookalike finds new people, while a custom audience can find people who already know you. That is why retargeting usually uses custom audiences and prospecting often uses lookalikes. Meta's newer Advantage+ audience option treats an audience you provide as a suggestion, so the AI can go beyond it. Whichever you use, check audience overlap so two ad sets don't compete for the same people.
Example. A meal-kit service uploads its 2,000 best subscribers, those who stayed for six months or more, and builds a lookalike audience from them. It runs one ad set on the lookalike and one on a broad audience, with the same ad and the same budget of $50 a day each, for seven days. The lookalike ad set spends $350 and brings 14 trials, a cost of $25 per trial. The broad ad set also spends $350 and brings 10 trials, a cost of $35 per trial. The service keeps both running, because the lookalike is cheaper but the broad audience reaches people the lookalike doesn't, and it re-tests next month with a fresh source.
In Madgicx. The AI Marketer audits your Facebook and Instagram ad account and surfaces optimization opportunities, so you can see how your audiences are performing next to each other. You decide which recommendations to act on.
FAQ
What is a lookalike audience on Facebook?
It is an audience Meta builds from a source you provide, made up of new people who share traits with that source. You use it to reach likely customers who haven't heard of you yet.
What is a good lookalike audience percentage?
There is no single best number. Smaller percentages match the source more closely and larger ones reach more people. Pick the size that fits your budget, then compare two sizes in an A/B test.
What should a lookalike audience be based on?
Base it on the people you most want more of, such as repeat buyers or high-value customers. A source built from your real results usually works better than one built from casual interest.
Do lookalike audiences still work with Advantage+ audience?
Yes, you can still use them. They are one way to give Meta a starting point, and Advantage+ audience lets Meta go beyond your inputs. Test the two against each other with your own data.
Do lookalike audiences need good tracking?
If your source comes from the pixel or server events, yes. Accurate conversion tracking means the source holds your real customers.
Related
- Related terms: Custom audience, First-party data, Retargeting, Audience overlap
- In depth: Why Facebook lookalike audiences are worth your ad spend
Sources
- Meta's lookalike audience overview, Meta Business Help Center
