Lookalike audience
similar audienceA lookalike audience is an audience the ad platform builds by machine to resemble a source you provide, for example your best customers. The platform finds users whose behaviour matches the seed, extending your reach to unknown but similar people.
Good to know
A lookalike’s quality is directly the seed’s quality: an audience built from your best customers brings more of the same, one built from all site visitors brings more randomness. A narrow, valuable seed such as repeat buyers beats a broad, diluted one.
Since the signal loss era, platforms’ automatic expansions have eroded the lookalike’s special status: Meta’s Advantage+ does the same work under the hood. The lookalike remains a useful way to feed the algorithm your first-party data as a compass.
IN PRACTICE
Building a working lookalike
Choose a valuable seed
Buyers, best customers or long-term users. At least a few hundred people, preferably thousands.
Start with a narrow percentage
1 % of the population resembles the seed most closely, 10 % most broadly. Start narrow, widen when results carry.
Keep the seed self-updating
Tie the source audience to the pixel or a continuously syncing customer list so the audience lives with your customer base.
PITFALLS
Two lookalike mistakes
All visitors as the seed
Site visitors include passers-by and bots. A lookalike built from them clones noise, not customers.
Lookalike stacked with interests
Interest filters layered on a narrow lookalike shrink the audience until delivery fails. Let the algorithm do its work.
FREQUENTLY ASKED
Frequently asked questions
How large a seed audience is needed?+
Platforms accept a hundred people, but a reliable model comes from thousands. With a small seed, use your most valuable data: buyers.
Which lookalike percentage should I pick?+
In Finland, 1 % is roughly 50,000 people. Start at 1–3 %; expand to 5–10 % only as the narrow audience starts to dry up.
Does lookalike work in B2B?+
Moderately: consumer platforms model people, not companies. Seed with decision-makers and customers’ key people, not the whole contact list.
Which channels offer lookalikes?+
Meta, TikTok, Snapchat and LinkedIn have their own; Google’s equivalent is a signal-based similar-audience expansion.
Why does lookalike not perform like it used to?+
Tracking restrictions have narrowed the platform’s view, and automatic audiences do part of the same work. The lookalike is now one input among many, not a magic trick.
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Maintained by the VSCY editorial team · Updated 6 Aug 2026 · Part of the marketing glossary (99 terms)
