How to Use Lookalike Audiences

A lookalike audience is a prospecting tool that helps advertisers find new people who resemble existing customers or leads.

Use one by starting with a high-quality source audience, creating a similar audience on your advertising platform, applying it to a conversion-focused campaign, excluding existing customers where appropriate, and comparing the results with broad targeting. A source might include purchasers from the last 180 days, high-value customers or qualified leads.

Meta calls the feature a Lookalike Audience, TikTok uses the same term, and Google Ads calls it a Lookalike segment.

Lookalike Audiences at a Glance

Decision	Recommended approach
Best campaign use	Prospecting and customer acquisition
Best source audience	Recent purchasers, high-value customers or qualified leads
Weak source audience	All visitors, low-quality leads or unqualified social engagers
Main benefit	Finds new users who resemble people already showing valuable behavior
Main risk	A poor source audience produces a poor-quality lookalike
Success metrics	CPA, CAC, conversion rate, revenue and lead quality
Should you exclude existing customers?	Usually yes for acquisition campaigns

What Is a Lookalike Audience?

A lookalike audience is a group of potential customers selected because they resemble people in an existing source audience. The advertising platform analyzes signals from the source audience and uses its models to find similar people.

A source audience might include:

Customers who completed a purchase
Customers with high lifetime value
Qualified leads
Repeat purchasers
Free-trial users who became paying customers
People who completed a key website action
App users who reached an important milestone
Video viewers or social media engagers

A lookalike audience is different from a retargeting audience. Retargeting reaches people who have already interacted with your business. Lookalike targeting reaches new people who resemble those existing users.

Step 1: Choose the Right Source Audience

The source audience matters more than its size. Choose people who have already shown the behavior you want to acquire.

Match the source to the campaign objective:

Purchasers, for ecommerce sales
High-value purchasers, when customer values vary significantly
Qualified leads or closed-won customers, for B2B services
Paid subscribers, for subscription businesses
High-intent website visitors, when you do not have enough conversion data
Engaged users, such as video viewers, as a secondary test

An ecommerce brand should generally start with recent purchasers rather than every website visitor. A B2B company should use qualified opportunities or closed-won accounts rather than everyone who downloaded an ebook.

Avoid combining audiences with very different levels of intent. A list containing purchasers, abandoned browsers and casual social engagers may give the platform a less useful pattern to model.

Use Value-Based Data When Available

If your platform supports value-based audiences, provide customer value data when creating the source. This helps the system distinguish high-value customers from one-time or low-value buyers.

For example, a clothing retailer could build a source from customers with the highest order values or repeat-purchase rates instead of using its entire customer database.

Step 2: Create the Lookalike Audience

The menu names vary by platform, but the process is similar:

Open the platform's audience or audience manager tool.
Create or select a source audience.
Choose the source for the lookalike.
Select the target country, region or market.
Choose the available audience size or similarity setting.
Create and save the audience.
Apply it to a prospecting campaign.

Meta Ads

In Meta Ads Manager, create the source as a Custom Audience, then use the audience creation tools to build a Lookalike Audience. Meta's training materials describe lookalike creation as a way to use customer lists, website activity, app activity or engagement data to find new people similar to the source.

A typical Meta workflow is:

Go to Audiences in Ads Manager.
Select Create audience.
Choose Lookalike audience.
Select the Custom Audience or another eligible source.
Choose the target location.
Select the available similarity or reach level.
Create the audience.
Select it in the ad set for a prospecting campaign.

Meta's interface and campaign options can change, so use the labels shown in your Ads Manager account.

TikTok Ads

TikTok Lookalike Audiences can use Custom Audiences created from engagement, app activity, website traffic, customer files and other supported sources. TikTok provides three size options: Narrow, Balanced and Broad. Narrow prioritizes similarity, while Broad increases potential reach. TikTok states that the minimum source audience size for creating a lookalike is 1,000 people.

A useful test is to create:

One Narrow lookalike for similarity
One Balanced lookalike for a compromise between scale and similarity
One Broad lookalike for reach

Broad will not always perform worse. It may give the platform more room to find converters, particularly when the campaign has strong conversion signals.

Google Ads

Google Ads uses the term Lookalike segments. These are available in Demand Gen campaigns and use first-party data sources such as customer lists, website visitors, app users or YouTube audiences.

Google says Lookalike segments in Demand Gen are transitioning during 2026 from strict similarity thresholds towards an audience-suggestion model. The seed list can act as a signal while Google optimizes towards campaign goals such as conversions or cost per action.

For Google Ads, use recent converters or high-intent customer lists as the seed. Judge the result by conversions and cost per action rather than by how closely the final audience appears to match the original list.

Step 3: Use the Lookalike in a Prospecting Campaign

A lookalike audience is designed for customer acquisition, so use it in a campaign built around new conversions.

Set up the campaign with:

A conversion or sales objective
A landing page that matches the ad promise
Creative for people unfamiliar with your brand
A clear offer or reason to act
Geographic and age restrictions where needed
Exclusions for existing customers, recent purchasers and active leads

The audience does not replace a strong offer. It helps identify potential customers, but the ad, landing page, pricing and checkout experience still affect whether those people convert.

Exclude Existing Customers

Exclude existing customers when the campaign's goal is customer acquisition. Otherwise, prospecting spend may reach people who have already purchased.

Google states that Demand Gen Lookalike segments automatically exclude users in the seed list. On other platforms, check the campaign settings and add customer exclusions manually where necessary.

You may keep existing customers in the audience when the campaign is for:

Cross-selling
Upselling
Subscription renewal
Repeat purchases
Promoting a different product category

Step 4: Test the Audience Properly

Do not judge a lookalike audience by click-through rate alone. Compare it with another prospecting approach using the same conversion event and a similar creative setup.

Test	What it tells you
Narrow versus Broad lookalike	Whether similarity or reach matters more
Purchaser source versus lead source	Which customer signal is more valuable
Lookalike versus broad targeting	Whether the model adds value over platform optimization
Recent source versus older source	Whether customer behavior changes over time
High-value source versus all customers	Whether quality improves when the seed is more selective

Track:

Cost per acquisition
Conversion rate
Customer acquisition cost
Revenue or return on ad spend
Average order value
Lead-to-opportunity rate
Lead quality
Repeat purchase rate

Keep the conversion event consistent. Comparing one audience optimized for purchases with another optimized for landing-page views will not produce a meaningful audience test.

Common Lookalike Audience Mistakes

Using Every Customer in One Source

A source containing inactive customers, refunds, low-value orders and unqualified leads may model the wrong behavior.

Create separate sources for purchasers, repeat buyers, high-value customers and qualified leads.

Building a Lookalike From Low-Intent Engagement

Video views and social engagement can help when you lack conversion data, but they do not necessarily represent buying intent. Treat these sources as tests rather than substitutes for customer data.

Changing Too Many Variables at Once

If you change the audience, creative, landing page, offer and optimization event at the same time, you will not know what caused the result.

Test the audience while keeping the rest of the campaign reasonably consistent.

Assuming a Smaller Audience Is Always Better

A narrow audience may be more similar to the source, but it can limit reach and increase delivery costs. A broader audience may produce more conversions if the platform has enough data and a clear optimization goal.

Ignoring Privacy and Data Permissions

When uploading customer lists, you need the appropriate rights, permissions and lawful basis to use the data for advertising. Meta's Customer List Custom Audiences terms place responsibility on the advertiser for obtaining the necessary permissions and complying with applicable laws.

A Practical Example

An online fitness subscription company wants to acquire more paying members.

It creates three source audiences:

Customers who subscribed in the last 180 days
Customers with at least two completed payments
Website visitors who viewed pricing but did not subscribe

The company creates a lookalike audience from each source, excludes current subscribers and runs the same prospecting creative against each group.

The largest source is not automatically the best one. The company should choose the source that produces the best combination of acquisition cost, subscription conversion rate and customer retention.