What is a lookalike audience?

A lookalike audience is a group of new people who share traits—like interests, behaviors, demographics—with your existing audience or customers. Platforms such as Facebook, Instagram, LinkedIn, or Google Ads use your source audience data (like website visitors or customer lists) to build these new groups for your ads. You feed in your known audience, the platform analyzes what makes them tick, and then finds others who match.

Why should you use a lookalike audience?

Creating a lookalike audience helps you:

  • Expand reach efficiently: Target people who are likely to care about your brand, not just random users.
  • Improve ad performance: More relevant targeting often leads to better engagement, clicks, or conversions.
  • Save on budget and time: Let smart algorithms handle audience building so you don’t waste money or effort manually picking interests.

How do platforms build a lookalike audience?

When you upload a source audience—like a customer list, website visitors, or people who liked your page—the platform examines data such as:

  • Age, gender, location
  • Interests, behaviors, engagement
  • Purchase history or site activity
    It then finds users with similar patterns and forms your lookalike audience. You can define how closely they should match, typically selecting a size range from 1% (very close match) to 10% (wider reach) of a country’s population.

What makes a source audience effective?

A strong source, or “seed,” audience should be:

  • Homogeneous: similar behaviors or traits (e.g. top 1,000 buyers)
  • Big enough: platforms like Facebook require a minimum (often 100+)—but 1,000–5,000 or more gives better results.

Examples include:

  • Loyal customers with high lifetime value
  • Recent purchasers or converters
  • Frequent site visitors or page engagers

This helps your lookalike algorithm pick up clearer patterns to find matching people.

How do you choose your audience size?

Smaller size (e.g. 1–2%):

  • Closer match, more niche
  • Often better performance and higher conversion
  • Smaller total reach

Larger size (e.g. 5–10%):

  • Broader reach, includes more people
  • Less precise but useful for scaling or brand awareness
  • Potentially lower conversion per person

Testing different sizes helps you find the sweet spot.

When should you use lookalike audiences?

Lookalike targeting works well when:

  • You’re launching a new campaign or product and want to scale
  • You’re entering new markets or regions beyond your existing customer base
  • You’ve found a successful ad or audience and want to expand it
    As long as you have a solid seed audience, it’s one of the best ways to grow without guessing who might convert.

Tips & Best Practices

  • Use a high-quality seed audience: Opt for your best or most active users.
  • Start with 1–2% size: Targeting tight often gives better ROI, then scale.
  • A/B test audience sizes: Run campaigns with different sizes to compare performance.
  • Refresh your source data regularly: Keeping the source list up to date improves relevance.
  • Respect data privacy: Ensure you follow laws and platform policies when uploading customer info.

Quick Scenario

Imagine you’re selling eco‑friendly water bottles. You use your top 2,000 repeat buyers as a source audience. On Facebook, you create a 1% lookalike targeting your local region. That gives you a small, highly targeted group—people whose profile resembles your best buyers. As your campaign converts, you expand to 5% to reach more eco-conscious shoppers. You see better results than targeting “outdoor enthusiasts” manually, and you didn’t waste budget on uninterested users.

Lookalike audiences take the guesswork out of targeting. They help you reach new people who are likely to care about your brand—based on real data, not assumptions. Use them wisely, test smart, and you’ll get more from your ad spend while growing your audience.