Checked 19 October 2026

Custom audiences on ChatGPT Ads

You can upload a customer list and use it to include, exclude or bid differently on people in ChatGPT. The rules are strict: 25,000 matched users to target a list, no access to who matched, and no audiences at all in Europe.

25,000

Matched users to target a list

Needed to include a list or set a bid multiplier on it. Exclusions have no minimum.

OpenAI Ads API docs, Oct 2026

0.1x to 10x

Bid multiplier range

On fixed bids only. If someone is in 2 lists, the highest multiplier wins.

OpenAI Ads API docs, Oct 2026

~24 hours

Before your file is deleted

OpenAI says uploaded files are deleted after processing.

MobileSyrup, citing OpenAI, 16 Oct 2026

What you can upload

5 kinds of identifier, mixed if you like

A list is a CSV or TXT file of up to 500 MB. Since 25 August 2026 one CSV can mix several identifier types.

Identifier	Format
Email	Plain email address. OpenAI trims it and makes it lowercase.
Phone	E.164 format, with the + and the country code, like +14155550123.
Hashed email	SHA-256 of the trimmed, lowercase email, as 64 hex characters.
Hashed phone	SHA-256 of the E.164 number, as 64 hex characters.
Android GAID	The raw Google Advertising ID. Do not hash it, OpenAI does that.

Before you hash an email, trim the spaces and make it lowercase. Do not remove dots or plus tags. Before you hash a phone number, put it in E.164 format. Hash it as plain text and send the 64 character hex result, not Base64. Full rules are in OpenAI’s custom audiences guide.

Apple’s IDFA is not on the list. OpenAI also asks you to upload only first-party data you have the right to use for ads, and says not to upload lists bought from data brokers.

3 ways to use a list

Include, exclude, or bid differently

Each use has its own size rule. Most small businesses start with exclusions, because they have no minimum.

Use	What it does	Minimum size
Include	Only people in the list can see the campaign	25,000 matched users
Exclude	People in the list never see the campaign	No minimum, even an empty list
Bid multiplier	Bid more or less for people in the list. Everyone else still sees the ad	25,000 matched users, fixed bids only

The 25,000 rule counts matched people, not rows

Uploading 25,000 emails does not give you 25,000 matched users. Only people OpenAI can match to a ChatGPT account count. OpenAI calls 25,000 a “planning threshold” and says privacy safeguards can move the exact line. PPC Land reports that OpenAI recommends 100,000 or more.

Exclusions always win

If someone is in an included list and an excluded list, they do not see the ad. You cannot put the same list in both. And if you combine the two, what is left after the exclusion must still reach 25,000 matched users.

A multiplier is not a filter

Including a list shuts everyone else out. A bid multiplier does not. A 2x multiplier on past customers bids double for them, and new customers can still see the ad at your normal bid. Multipliers only work with fixed bids. Maximize Results ad groups cannot use them.

A good first list

Exclude people who already bought. It needs no minimum, it works as soon as it shows ready, and it stops you paying for clicks from existing customers.

An empty list excludes nobody

Since 25 August 2026 you can create an empty exclusion list and fill it later. It does nothing until people are added and it shows as ready.

Keeping a list fresh

4 ways to update a list

You do not need to rebuild a list when customers change. Since 25 August 2026 there are 4 update operations.

Operation	What it does
Add	Adds new people. Existing members stay.
Remove	Takes out the people in your file. Everyone else stays.
Replace	Swaps the whole list for a new file. Same audience ID, so campaigns keep working.
Merge	Combines 2 to 64 lists into a new, separate audience.

How long it takes

Every upload and update runs in the background. OpenAI says the time depends on the size of the file. PPC Land reports 20 to 30 minutes is usual. A list that shows ready can still fail the size check, so check it is eligible for the use you want.

What you can see, and what you cannot

Match counts come back as ranges only: under 25k, 25k to 100k, 100k to 500k and up. OpenAI never shows exact counts, and never shows which person matched. Updates can also be refused if they would push a live campaign under the minimum.

Merged lists do not update

A merged list is a copy. If you add people to one of the source lists later, the merged list does not change, and campaigns do not switch to it on their own.

Everything else

The other targeting layers, and the limits

Audiences sit on top of the other settings. They do not replace them.

Settings that work with audiences

Location: country, region or market, up to 2,500 IDs to include or exclude. Product feed campaigns work at country level only.
Platform: iOS app, Android app and web, with web split into desktop, iOS and Android web since September.
Context hints and exclusion hints: set on each ad group. OpenAI says they are not exact-match keywords. Our targeting guide covers how to write them.

All of these combine. Being in an included list does not override a location or platform setting, as OpenAI’s targeting docs explain.

No lookalikes

We found no lookalike or similar audiences in the API docs or in press coverage. OpenAI has not announced one.

Not in Europe

Custom audiences are not supported for campaigns that target the EEA or Switzerland, where personalised ads are not available yet. There, ads are matched on the conversation only.

Why this was in the news

From 15 to 17 October 2026, Yahoo Tech, MobileSyrup and others covered the feature from a privacy angle. The feature itself is older: gated in May 2026, documented in July, expanded on 25 August.

One point from that coverage: turning off ad personalisation does not stop ads based on the chat you are having right now.

Questions

Can I upload my customer email list to ChatGPT Ads?

Yes, outside Europe. You can upload emails, phone numbers in E.164 format, SHA-256 hashed versions of both, or Android advertising IDs. OpenAI says to upload only first-party data you have the right to use for ads, never bought lists.

How big does a ChatGPT Ads custom audience need to be?

25,000 matched users to include a list or set a bid multiplier on it. Matched users is not the same as rows in your file, so 25,000 emails will usually match fewer people. PPC Land reports that OpenAI recommends 100,000 or more. Exclusion lists have no minimum.

Can I see which of my customers matched?

No. OpenAI only shows match counts as ranges, like under 25k or 25k to 100k. It never shows who matched or who did not.

Does ChatGPT Ads have lookalike audiences?

We found none. Lookalike or similar audiences are not in the Ads API docs or in any press coverage we read. If OpenAI adds them, we will update this page.

Can I use custom audiences in France, Germany or the UK?

Not in the EEA or Switzerland. OpenAI says custom audiences are not supported for campaigns that target those countries, because personalised ads are not available there yet. The UK is not in the EEA. OpenAI has not published a separate UK rule for audiences.

How long does an audience upload take?

OpenAI says processing time depends on the size of the file. PPC Land reports it usually takes 20 to 30 minutes. Wait for the status to show ready, then check it is eligible for the use you want.

A list only narrows who sees the ad. Context hints still decide which conversations it shows in.

How targeting works Inside Ads Manager

Keep this page useful

The audience rules already changed once this year, on 25 August. We send a short monthly note on what changed and whether it matters to you.

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