The Complete Guide to Meta (Facebook) Custom Audiences

Most advertisers I meet sit in one of two camps with custom audiences. One camp says “I know this, it’s for retargeting”, then follows people for months. The other camp opens the custom audience screen, sees a dozen options and closes it again.

Here’s the short answer. A Meta custom audience is a group of people you own: your website visitors, your customer list, your video viewers, the people who engaged with your page or opened your lead form. You use them for two jobs only. Retargeting, with a short window, and exclusion, with a long one. Get those two jobs right and most of the confusion goes away.

What a custom audience is, and what it isn’t

A custom audience is built from something you own. If the pixel sits on your website, you can build audiences from your visitors. If the customers are yours, you can upload the list. If the video sits on your page, you can build an audience of the people who watched it.

That’s why you can’t target your competitor’s website visitors or your competitor’s customers. You don’t own their website, so your pixel isn’t on it, and you don’t own their list. People ask me this all the time. The answer is always no.

Custom audiences are also the source for lookalike audiences, which are different. A lookalike is new people who resemble an audience you own. I cover the difference in custom audiences vs lookalike audiences.

Retention: how long someone stays in an audience

Every custom audience has a retention period. It works first in, first out. If your audience is “visited the website in the last 30 days”, someone who visits today stays in it for 30 days counting from today. On day 31, they drop out. Someone who visits in two weeks’ time starts their own 30 days from that day.

You set it once and it keeps flowing. You don’t need to relaunch anything on day 7 or day 30. People move in and out on their own.

Each type has its own maximum. At the time of writing, these are the limits I work with:

Custom audience type	Maximum retention
Website (pixel and conversion API)	180 days
App activity	180 days
Offline activity	180 days
Customer list	No expiry
Video, Facebook page, Instagram account	A year, and longer for some engagement types
Facebook events	365 days
Lead form	90 days

Meta changes these limits from time to time, so check the number Ads Manager shows you when you create the audience.

The two jobs: retargeting and exclusion

This is the rule I repeat most. Retargeting gets a short window. Exclusion gets a long one.

Retargeting means showing a follow-up ad to people who showed interest but didn’t act. The window should match how long people take to decide to buy from you. For most of my campaigns that’s 3, 7 or 10 days. Think about what you sell. If people don’t take a month to decide, a 30-day window doesn’t make sense, and 180 days makes even less.

Imagine you build a 365-day video audience and run retargeting to it non-stop. Anyone who watched half your video sees that ad for a whole year. That’s how retargeting budgets leak. I go deeper into picking the window in how long your retargeting window should be.

Exclusion means keeping people out of an ad. I use custom audiences for exclusion far more than for retargeting. My cold ads should keep reaching fresh people, so anyone who has recently visited my website, engaged with my page or Instagram, or submitted a lead doesn’t need to see them again. For exclusion I go long: 90 days is common for me, and some ads exclude website visitors for 180 days.

Here’s the thing. If someone has already met you and didn’t buy, your retargeting follows them anyway. Your cold ad showing up again doesn’t add anything. Excluding them keeps your cold budget on new people.

Website custom audiences

With the pixel installed, you can build audiences from all website visitors, from people who visited specific pages, and by time spent. If you run an e-commerce store, you can also build from events like add to cart, initiate checkout and purchase.

How I use them:

• All website visitors: mostly for exclusion, 90 to 180 days, so my cold ads keep finding new people.
• Specific pages: for retargeting, usually 7 days. Use “URL contains”, not “URL equals”. When people click from an ad, extra tracking text gets added to the link, and “equals” would miss them.
• Pages but not others: for example, visited the product page but not the thank-you page. Useful, but keep it simple.
• Purchasers: a separate audience, for example purchased in the last 30 days, kept as an exclusion.

One rule I follow strictly. One custom audience does one job. Don’t build a single audience that includes page visitors and also excludes purchasers. Build two audiences and combine them in the ad set. I’ve been doing this for over ten years, and complicated audiences always end up confusing the person who built them.

Customer list custom audiences

Upload a CSV of your customers, with emails, phone numbers and country, and Meta matches them to profiles. The data is hashed before matching. You can add a customer value column if you have it, which gives Meta more to learn from when you build a lookalike later.

Customer lists don’t expire, so they’re useful in two ways. Exclude past customers from offers meant for new people. Or retarget them when you have something worth telling them, like a big sale day.

If you sell on a marketplace where you can’t install a pixel, your customer phone numbers are still yours. Upload them and update the list weekly or monthly, and you can exclude buyers even without tracking. More in how to use a customer list custom audience.

Engagement custom audiences

These come from people interacting with you on Meta itself.

Video. You can target people who watched at least 3 seconds, 10 seconds, ThruPlay, or a percentage up to 95%. You can select several videos in one audience. I use video as an audience qualifier: if someone watches enough of my first ad, they see my second ad, and they stop seeing the first one. More in video engagement custom audiences.

Facebook page and Instagram account. Everyone who engaged, profile or page visitors, people who engaged with any post or ad, people who messaged you, people who saved a post. My default use: people who engaged in the last 90 days, kept as an exclusion. If your business runs on DMs, a short retargeting audience of people who recently messaged you is worth testing, for example 7 days, so they see you while you’re still talking.

You can’t target people who engaged with one specific post. If you need that, make the post a video, because video audiences can be built per video.

Lead form. This one matters if you run lead ads. Build “submitted the form” for 90 days and exclude it. Without it, the same people submit again and you pay twice for the same lead. When you create a new form, add it to that audience. For people who opened but didn’t submit, retarget for about 7 days, see lead form opened but not submitted.

Instant experience. You can target people who opened it or clicked a link inside it. Clicking is deeper intent than opening. Start with clickers, and if the audience is too small for the ad to run, switch to openers. I use openers for 7 days to retarget and for 60 days to exclude.

Events. People who responded going or interested, and more. I only promote events to warm people, so I keep a 365-day event audience and use it to promote the next event. More in is an event custom audience worth it.

App, offline and shopping audiences

App activity works like the website pixel, using the SDK in your app. You can target by actions like add to cart or purchase, as long as the app is linked to your ad account.

Offline activity needs your point-of-sale data connected to Meta. I’ll be honest, I haven’t had a meaningful case with offline audiences, so I won’t pretend to have a method for them.

Shopping and catalog audiences cover people who viewed products, saved them or added them to a basket in a Facebook or Instagram shop, where shops are available. If you have both, create separate audiences for each.

Before you build any retargeting audience, know what a sale is worth to you. A short window is cheaper, but only your numbers tell you how much you can spend chasing one buyer.

Find your break-even ROAS with the free Know Your Numbers Scorecard →

Two minutes, no ad account access. You’ll see your break-even ROAS, your target ROAS, the most you can pay Meta for one sale, and what you keep or lose per $1,000 spent.

Managing audiences: edit, don’t rebuild

Go to the Audiences page in Ads Manager to see every audience in one place. Two habits save a lot of mess.

Edit instead of creating new. If you want to change a 7-day audience to 10 days, edit it there. When you change an audience from the Audiences page, the ad set keeps running as if nothing happened. Swapping a new audience into a live ad set can send it back into learning. Same with customer lists: click edit, add customers, upload the new file. See edit a custom audience without restarting learning.

Name it so anyone can read it. Put the source, the action, the days and the job in the name, like “Website all visitors 90 days EXCLUDE” or “IG engaged 90 days EXCLUDE”. Long is fine. If you edit the duration, change the name too. Once you build separate audiences for retargeting and exclusion, you’ll have a lot of them, and the name is the only thing that tells you what each one does a year from now.

The mistakes I see most

• Retargeting windows that are far too long. 30, 60, 180 days for products people decide on in a week.
• No exclusions on cold ads. The same people keep seeing the same cold ad and frequency climbs.
• Not excluding lead form submitters. You pay for duplicate leads.
• One audience trying to do two jobs. Include and exclude rules mixed in one audience.
• Creating a new audience for every change instead of editing the existing one.
• Retargeting audiences so narrow the ad can’t spend. Widen the action (openers instead of clickers) before you widen the window.
• Building lookalikes from weak sources. Page visitors make a poor seed. Purchasers make a good one.

For a full set of related guides, see the custom audiences resource library.

A quick self-check

• Is every retargeting window based on how long your customers take to decide?
• Do your cold ads exclude recent website visitors, engagers and lead submitters?
• Does each custom audience do only one job?
• Would someone else understand every audience name in your account?
• Is your customer list up to date?
• When you last changed an audience, did you edit it or create a new one?

If you answered no to more than two, fix your exclusions first. That’s usually where the budget leaks.

Frequently asked questions

What is a custom audience in Meta ads?

A custom audience is a group of people you own the data for, such as your website visitors, your customer list, people who watched your videos, or people who engaged with your page or lead forms. You use it to retarget people who showed interest, or to exclude people who shouldn’t see an ad again.

How long should a retargeting custom audience be?

Match it to how long your customers take to decide to buy. For most of the campaigns I run, that’s 3, 7 or 10 days. Long windows like 90 or 180 days are better kept for exclusion, not retargeting.

Can I create a custom audience from my competitor’s customers?

No. Custom audiences only work with data you own, like your own website, your own customer list or your own page and videos. You can’t build one from a competitor’s website visitors or customers, and you can’t build a lookalike from them either.

Does editing a custom audience restart the learning phase?

Editing an existing audience from the Audiences page, such as changing its duration or adding customers to a list, keeps your ad set running without going back into learning. Swapping a brand new audience into a live ad set is the change that can restart learning.

Want me to look at your audiences with you?

The scorecard tells you what a sale is worth. It can’t tell you where your audiences are leaking. The Know Your Numbers Assessment is a 90-minute session with me on screen share. We go through every ad against your numbers, look at your landing page and offer, and you leave with a written plan of what to fix first, plus the recording.

Written by Jason Gan, a Meta ads strategist who has run Meta ads since 2010 and personally audited more than 1,000 ad accounts. Meta Certified Professional and Badged Meta Business Partner. Watch real account breakdowns on his YouTube channel.