What is a lookalike audience, and how do you set it up?
A lookalike audience lets Meta reach new people who share characteristics with an audience you already have, such as your customers. Meta uses information like demographics, interests and behaviors from that source to find similar people, and leaves out the people already in it. The source needs at least 100 people, and Meta generally recommends 1,000 to 5,000. You then choose a percentage of the population in your ad set’s locations: 1% holds the people most similar to your source, and higher percentages, up to 10% in the audience size selector, make the audience bigger and broader. Two things changed recently. New lookalikes no longer carry their own location: they use the ad set’s location settings. And Advantage+ lookalike, switched on automatically for new ad sets using most lookalikes, lets Meta deliver beyond your percentage when it expects better performance. With Advantage+ audience, a lookalike you include works as a suggestion, not a hard limit.
What is a lookalike audience on Meta?
A lookalike audience is a group of new people Meta finds because they resemble an audience you already care about, such as your customers or your leads. Meta looks at information like demographics, interests and behaviors in your source audience, then delivers your ads to people who share those qualities.
You build it from a custom audience, a Page or a Meta Pixel, with the right permissions on each; saved audiences cannot be a source. You can create up to 500 lookalikes from one source, and put several lookalikes in one ad set: the ad set then reaches people in any of them.
Meta limits or removes lookalikes for some ads about financial products and services, employment or housing, and restricts targeting options for audiences that include people under 18.
How big should the source audience be?
Meta requires a source of at least 100 people and generally recommends 1,000 to 5,000. Size is not everything: Meta notes you may get better results from a source built on your best customers than from one that includes all of them. The quality of the source shapes the quality of the lookalike.
People in the source are excluded from the lookalike, so the audience you get is made only of new people. A lookalike takes up to 3 days to populate. You can start running ads right away, but the audience keeps growing while it populates. If the status reads Audience not created, the source was probably too small.
For a value-based lookalike, you start from a custom audience that includes a value column, then choose the size with the same slider.
Which lookalike percentage should you pick, from 1% to 10%?
The percentage sets how close the lookalike stays to your source. Meta’s audience size selector goes from 1% to 10% of the population in your ad set’s locations. A 1% lookalike holds the people most similar to your source; each step up makes the audience bigger and broader, and less similar.
Meta says the right size depends on your goals: a small percentage gives a close match, a larger one gives delivery more people to work with. You can also build a set of lookalikes that do not overlap, such as 0 to 1%, 1 to 3% and 3 to 6%, to bid differently on each slice.
Because new lookalikes use the ad set’s locations, Audience Manager no longer shows an estimated size when you create one. You see the estimate in the ad set, where the location is set.
| Percentage | Similarity to the source | Audience size | What Meta says |
|---|---|---|---|
| 1% (0% to 1%) | Highest | Smallest | The people most similar to your source |
| 1% to 3% | High | Larger | Second most similar slice in Meta’s lookalike set example |
| 3% to 6% | Lower | Larger still | Least similar slice in the example |
| Up to 10% | Lowest | Largest | A bigger, broader audience |
Percentages apply to the population of the locations set in your ad set. Meta’s selector goes from 1% to 10%.
What changed for lookalikes with Advantage+ audience?
Lookalikes now work more like a starting point than a fence. With Advantage+ lookalike, Meta can deliver your ads to people outside the percentage you chose when it expects better performance. It switches on automatically for new, duplicated and draft ad sets that use lookalikes built from website, app or customer list audiences.
Advantage+ audience goes further. Meta’s AI finds the audience from signals such as past conversions, Meta Pixel data and interactions with previous ads. In that setup, custom audiences you include are audience suggestions: Meta shows ads to people who match them, and to others when that is likely to improve performance.
Hard limits live in audience controls: locations, minimum age, custom audiences to exclude and languages. If reaching a specific audience matters more than performance, Meta says to select Further limit the reach of your ads, which turns your inclusions into controls; you may have to uncheck Use as a suggestion.
Meta recommends A/B testing Advantage+ audience for almost all campaign types, except retargeting. For a lookalike, that means testing it as a suggestion against the same lookalike as a strict limit, rather than assuming one wins.
What does a lookalike limit, and what does it only suggest?
Under Advantage+ audience, Meta sorts your settings in two groups. Controls are hard limits. Suggestions, including the custom audiences you include, guide delivery without fencing it.
Audience controls
Meta never delivers outside these.
- Locations
- Minimum age
- Custom audiences to exclude
- Languages
Audience suggestions
Meta can go beyond these when it expects better results.
- Age
- Gender
- Detailed targeting
- Custom audiences to include
What mistakes should you avoid with lookalike audiences?
Most lookalike problems start with the source or with overlap. A tiny or mixed source gives Meta weak signals, and several lookalikes of the same customers in separate ad sets can end up chasing the same people. Check both before you blame the percentage.
- Building from every visitor when you have a list of buyers. Meta points to your best customers as the stronger source.
- Running 1%, 3% and 5% lookalikes in separate ad sets with no exclusions. Meta’s lookalike sets are non-overlapping by design; separate lookalikes are not. See ad sets that compete with each other.
- Forgetting that Advantage+ lookalike may be on. If you must stay inside the percentage, check the setting in the ad set.
- Judging a new lookalike too early. It can take up to 3 days to populate.
What should you read next?
A lookalike is one audience among several. These pages help you launch with the right ones and keep ad sets from competing.