Lookalike scaling — when to expand to 10%

Quick Answer

Expand to a 10% lookalike when (a) your CPA on smaller percentages has crept above target, (b) your daily spend has plateaued, and (c) you have stripped away every smaller-percentage layer using exclusions. The 10% audience is huge, low-precision, and only useful as a scale lever once your tighter audiences are saturated. Always exclude the smaller percentages so you are not running over the same people twice.

When to expand and when to wait

The biggest mistake new advertisers make is jumping to a 10% lookalike too early. The 10% includes everyone in the 1%, 2%, 3%, ..., 9% — it is a massive audience with much weaker signal per person. If you launch on a 10% lookalike before exhausting smaller percentages, you waste budget on people Meta could have served more efficiently from a tighter audience.

Wait if:

• Your 1% lookalike still has CPA inside target


• You can still spend more in your 1% to 5% audiences


• Your account is under £500/day in spend


• You have not run lookalikes in this market before

Expand if:

• CPA on smaller percentages has been creeping up for 7+ days


• Daily spend keeps hitting a ceiling no matter how much you raise budget


• Frequency is climbing in tight audiences (signs of saturation)


• You have tested 1%, 2% to 3%, and 5% and need new inventory

Step-by-step setup

1. Confirm saturation in smaller audiences. Look at frequency, CPA trend, and spend ceiling. If the 1% is showing fatigue (frequency >3 with rising CPA), it is time to scale.
2. Build the 10% lookalike. Audiences > Lookalike. Same seed as before, set size to 5% to 10% (Meta lets you set ranges or single percentages).
3. Build exclusions. You need to exclude the 1%, 2%, 3%, and 4% audiences from the 10% ad set. Otherwise, 50% of impressions will hit people you are already running ads against.
4. Set up the new ad set. Use the 10% lookalike as the audience. Add exclusions: smaller lookalike percentages, existing customers, recent purchasers.
5. Use a higher daily budget than your 1% ad set. The 10% audience needs more spend to find converters because the signal is weaker.
6. Watch CPA closely for the first 7 days. Expect CPA to be 15% to 30% higher than the 1% — if it is more than 50% higher, the audience is too broad for your offer.

Real examples

DTC supplements brand, scaling from £400/day to £2,000/day. Started on 1% lookalike of purchasers, CPA £14. Spend ceiling at £600/day. Added 2% to 5% with 1% excluded — pushed to £1,200/day, CPA £17. Added 5% to 10% with 1% to 4% excluded — reached £2,000/day, CPA £21. Total revenue 5x, CPA up 50% but ROAS still profitable.

Online course, $497. 1% lookalike CPA $48. Tried jumping straight to 10% — CPA $112, the audience was too broad without first stripping out the smaller layers. Rebuilt with proper exclusions: 1% to 4% removed. CPA on the 10% layer settled at $74 — workable for the higher LTV.

Local services business. 1% lookalike inside a 25-mile radius was too small to spend through. Jumped to 5% to 10% with location constraint. Lookalike CPA was 22% higher but the local audience was big enough to spend the budget.

The exclusion trap

The number one mistake when scaling to 10%: forgetting exclusions. If you do not exclude smaller percentages, the 10% lookalike will heavily overlap with your existing 1% and 2% ad sets. You will end up bidding against yourself, frequency will spike, and CPA will deteriorate across the whole campaign.

FAQs

Should I always exclude the 1% from the 10%?
Yes, if you are running them in parallel. If the 1% ad set has been paused, you do not need the exclusion.

What is the maximum lookalike size?
10% of the population in your selected country. Larger than that is not available.

Will a 10% lookalike ever beat a 1% on CPA?
Rarely. The 1% almost always wins on cost per conversion. The 10% wins on volume — total conversions per day.

Can I use Advantage+ instead of building a 10% lookalike?
Yes, and many accounts now do. Advantage+ Audience treats your seed and lookalike as signals and explores beyond the 1% automatically. For mature accounts, this often outperforms manual scaling.

How long should I run the 10% before judging it?
7 to 14 days, with at least 50 conversions per ad set. Below that, you cannot trust the data.

Scale efficiently with the right creative mix

When you scale to broader audiences, your creative has to do more work — it is hitting people who are less perfectly matched to your offer. Pix-Vu tests creative variants against broader audiences so your scaled campaigns keep converting. Try Pix-Vu free at https://pix-vu.com.