# What is a custom audience on Meta?

> A custom audience is a Meta audience built from your own data or from people who engaged with you. The types, the 500 limit and a worked example in rupees.
- **Author**: Marxx
- **Published**: 2026-11-19
- **Category**: Meta
- **URL**: https://marxx.ai/library-glossary/custom-audience

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A custom audience is a Meta audience that you build from your own data or from people who engaged with you on Meta. You use it for retargeting, for new customer campaigns, or to leave certain people out ([Meta Help Center](https://www.facebook.com/business/help/744354708981227), checked 2026-10-20).

## The types

Built from your own data:

- **Website:** people who visited your site, tracked with the Meta Pixel.
- **App activity:** people who took actions in your app.
- **Catalog:** people who interacted with items in your catalog.
- **Customer list:** a list of emails or phone numbers you upload to match with Meta users.
- **Offline activity:** in-store purchases or other offline actions.

Built from Meta engagement: video views, lead form opens, Instant Experience taps, shop activity, Instagram account, Events, Facebook Page and Marketplace listings.

You can make up to 500 custom audiences per ad account. You can also build a lookalike audience from one.

## A worked example

Say you upload a list of 8,000 customer emails and phone numbers. Meta hashes the data, then matches it to profiles. 5,200 match.

- Match rate = 5,200 / 8,000 x 100 = **65%**

Meta says the more identifiers you give, the better the match rate. Adding phone numbers to a list that only had emails can raise it.

Now use the audience two ways:

1. **Exclude it** from your new customer [ad set](/glossary/ad-set), so buyers do not see "new customer" offers.
2. **Retarget website visitors** from the last 30 days. Say you spend INR 6,000 on them and get 12 purchases. That is INR 500 per purchase. Your prospecting ads cost INR 800 per purchase. The warm audience is cheaper, but it is small and runs out.

## Good habits

- Name audiences by source and window, such as "Site visitors 30d".
- Refresh customer lists so you do not keep selling to people who already bought.
- Feed Meta clean events. See the [Conversions API](/glossary/conversions-api).
- Do not lean on retargeting alone. It only reaches people who already know you.

With [Advantage+ audience](/glossary/advantage-plus-audience), Meta's AI finds the audience for you ([Meta Help Center](https://www.facebook.com/business/help/273363992030035), checked 2026-10-20). See also [broad targeting](/glossary/broad-targeting). Custom audiences still help to exclude buyers and retarget warm visitors.

## FAQ

### What is the difference between a custom audience and a lookalike audience?

A custom audience is people you already know of. A lookalike is a group of new people similar to them.

### Can I use a custom audience to leave people out?

Yes. Meta supports an exclusion-only custom audience. It is a customer list audience that can only be used to exclude people from your ad audience.

### Is a customer list safe to upload?

Meta hashes the information before use. Follow your privacy policy and get consent where the law needs it.

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