Facebook lookalike audiences help you reach new people who resemble your best customers. This guide walks you through every step in Ads Manager, from building your source audience to launching campaigns.
What Is a Facebook Lookalike Audience?
A lookalike audience is one of the fastest ways to find cold prospects worth targeting.
Definition and core concept
A lookalike audience is a targeting pool Facebook builds for you. It finds users who share behaviors, interests, and demographics with a group you already know converts.
How Facebook matches similar users
Facebook scans your source audience for patterns. It then finds users in your target country who match those patterns. The matching happens automatically. You don't configure the signals manually.
Key difference from custom audiences
Custom audiences are people you already have data on. Lookalike audiences are net-new prospects. They've never interacted with your brand. But they look a lot like people who have.
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What You Need Before Creating a Lookalike Audience
Have a source custom audience ready before you start.
Create a custom audience (source audience)
Go to Ads Manager and build a custom audience first. Use your customer list, pixel data, app activity, or engagement data.
Understand source audience requirements
Per Meta's Business Help Center, your source audience needs at least 100 people from the same country. Below that minimum, Facebook won't generate a lookalike.
Minimum and recommended sizes
The floor is 100 people. Meta recommends 1,000-5,000 people for best results. Higher-quality data matters more than a large list.
Supported data sources
Customer email lists, website pixel events, app activity, video viewers, and page engagers all work as valid sources.
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Step-by-Step: How to Create a Facebook Lookalike Audience
Access Audiences in Ads Manager
Open Meta Ads Manager. Click the grid icon and navigate to Audiences under "Advertise."
Select Create a Lookalike Audience
Click the "Create Audience" button. Choose "Lookalike Audience" from the dropdown menu.
Choose your source audience
Select the custom audience you prepared. This is the group Facebook models the lookalike from.
Select target country or region
Choose the country or region you want to reach. Your source audience doesn't need to include people from that country.
Adjust audience size and similarity
Use the slider to set your similarity percentage. Lower percentages (1-2%) match your source more closely. Higher percentages (8-10%) expand your reach but reduce similarity. You can create up to 500 lookalike audiences from a single source audience.
Review and create
Check your settings. Click "Create Audience." Facebook starts building your lookalike immediately.
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Lookalike Audience Size and Similarity Settings
The similarity scale controls the trade-off between quality and reach.
Understanding the similarity scale
The scale runs from 1% to 10% in most countries. A 1% lookalike is the smallest and most tightly matched. A 10% lookalike is the broadest.
Smaller = higher quality match
A 1% lookalike closely mirrors your source. Fewer users, but they're your most qualified cold prospects.
Larger = broader reach
A 10% lookalike covers far more people. The similarity is looser. Useful for scaling campaigns with bigger budgets.
Estimated reach previews
Ads Manager shows a live reach estimate as you move the slider. Check it before you commit.
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How Long Does It Take? Timeframes and Updates
Initial population time (6-24 hours)
Facebook takes 6-24 hours to fully populate a new lookalike audience. Don't launch campaigns before it's ready.
Automatic refresh schedule
Lookalike audiences update automatically. Pixel-based audiences refresh every 3-7 days. Value-based lookalikes refresh every 60 days. You don't need to rebuild them manually.
When to start using in campaigns
Wait until Ads Manager shows "Ready" status. Then add the audience to your ad set.
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Best Practices for High-Quality Lookalike Audiences
Choose your best customers for the source
Don't use your full email list. Use top buyers, repeat customers, or your highest-value segment. Source quality drives lookalike quality.
Test multiple similarity levels
Run 1%, 3%, and 5% audiences against each other. Find the sweet spot for your cost per acquisition.
Combine with other targeting parameters
Stack a lookalike with age, location, or interest filters to sharpen the fit.
Monitor and refresh regularly
If your source audience grows significantly, rebuild the lookalike. Fresh source data produces a more accurate match.
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Use Lookalike Audiences in Your Campaign
How to select in Ads Manager
At the ad set level, find "Custom Audiences" and add your lookalike. It works the same as any saved audience.
Pairing with creatives and copy
Your lookalike audience is only as strong as the ad it sees. Match your creative to what your best customers respond to. A Brand Profile in Coinis keeps your messaging consistent across every ad you generate, so nothing feels off-brand.
Faster with Campaign Launcher
Coinis Campaign Launcher walks you through audience selection, creative, budget, and publish in one wizard. Add your Facebook lookalike in the audience step. Attach AI-generated creatives. Publish directly to Meta without toggling between tools.
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Or let Coinis do it.
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Frequently Asked Questions
How many people do I need in my source audience to create a Facebook lookalike?
Meta requires a minimum of 100 people from the same country. For best results, Meta recommends a source audience of 1,000 to 5,000 people. Quality of the source matters more than hitting a large number.
How long does it take for a Facebook lookalike audience to be ready?
Facebook typically takes 6-24 hours to fully populate a new lookalike audience. Wait until Ads Manager shows 'Ready' status before adding it to a live campaign.
What is the best similarity percentage for a Facebook lookalike audience?
It depends on your goal. A 1% lookalike closely mirrors your source audience and suits high-intent prospecting. Higher percentages (5-10%) offer broader reach at the cost of similarity. Testing 1%, 3%, and 5% against each other is a common approach.
Do Facebook lookalike audiences update automatically?
Yes. Pixel-based lookalike audiences refresh every 3-7 days. Value-based lookalikes update every 60 days. You don't need to manually rebuild them as long as the source data stays active.