ChatGPT Ads Adds Flexible Attribution Windows — And Changed What Conversions Counts

OpenAI updated the ChatGPT Ads reporting documentation on 2026-09-16, and the headline feature — advertiser-selectable attribution windows — arrived with a side effect that is easy to miss and expensive to miss: the definition of the Conversions column changed.

Until this update, Conversions in Ads Manager was a click-through number. View-through conversions existed, but they sat outside it. As of this update, view-through conversions can be counted inside it, depending on a setting.

Everything below is read from OpenAI's own published documentation and verified on 2026-09-16, with the exact previous wording where it matters. Where OpenAI's two official surfaces disagree — and on this change they do — both are quoted.

What changed, in OpenAI's words

The Measure Results article previously described view-through conversions as supplemental. The prior wording read:

"For eligible accounts, Ads Manager may also show supplemental one-day view-through conversions. View-through conversions are reported separately from the main Conversions metric."

and, in the reporting section:

"Ads Manager displays a single Conversions total for the selected reporting scope and date range. This total includes click-through conversions only. View-through conversions, when available, are reported separately."

and it was unambiguous about the consequences:

"View-through conversions are supplemental reporting. They do not affect CPA, post-click conversion rate, bidding, billing, or conversion optimization."

The same article now reads:

"The Conversions total includes click-through and eligible view-through conversions based on your selected reporting windows. Click-through and view-through conversions can also be viewed separately."

and:

"Ads Manager displays a single Conversions total for the selected reporting scope and date range. This total includes click-through and eligible view-through conversions based on your selected reporting windows."

That is a reversal of the documented behaviour of the single most-read number in the account.

The new feature: flexible attribution windows

The mechanism behind the change is a new documented section, Flexible attribution windows:

"Ads Manager lets advertisers choose a 7-, 14-, or 30-day click-through reporting window and either 0 Day (disabled) or a 1-day view-through reporting window. Any supported combination can be used."

The link between the setting and the total is stated directly:

"When the view-through window is set to 1 Day, eligible view-through conversions are included in the Conversions total. Selecting 0 Day disables view-through attribution in reporting, so the total includes click-through conversions only."

Two guardrails are documented, and both matter:

"Changing the reporting window affects reporting only; it does not change campaign optimization, bidding, or billing. The feature uses OpenAI's existing last-touch attribution logic and is not multi-touch attribution."

So this is a reporting control. It does not change what the auction does, what you are charged, or what the conversion optimizer trains on. It changes what you see — which, for anyone whose reporting feeds a budget decision, is not a small thing.

To change it: open Campaigns, Ad groups, or Ads, select Edit columns, and under Conversion Events find Attribution windows.

The two official surfaces now disagree

This is the part to read carefully before you quote a number to a client.

OpenAI maintains two documentation surfaces for ChatGPT Ads: the help centre, and the developer documentation at developers.openai.com/ads. On 2026-09-16 the help centre changed. The developer documentation did not.

The developer docs — both the Measurement Pixel page and the Conversions API page — still read, at the time of writing:

"Ads Manager reports view-through conversions as a separate, campaign-level metric. They are not included in Conversions, which remains the click-through conversion total. CPA, post-click CVR, bidding, billing, and conversion optimization also remain click-through-based."

The help centre says view-through conversions are included in Conversions when the window is 1 Day. The developer docs say they are not included in Conversions at all. Both are live, both are official, and they describe the same column.

We are not going to pretend to resolve that. The most likely reading is that the developer documentation simply lags the help centre by a release — this is the same pattern seen on 2026-08-06, when a beta existed only in the developer docs and was absent from the help centre, just pointing the other direction. But "most likely" is not "documented", and an API integration written against the developer docs' explicit guarantee that Conversions "remains the click-through conversion total" is now built on a sentence that the help centre contradicts.

Treat the help centre as describing the Ads Manager UI, which is what it is scoped to, and treat the developer docs' claim as unverified until they are updated.

The number OpenAI has not published

Here is the gap that decides how much this costs you: OpenAI does not document a default.

The 2026-09-16 text describes the options (0 Day or 1 Day), and describes the effect of each on the Conversions total. It does not say which value an existing account is on, or which value a new account starts on. There is no "defaults to" sentence anywhere in the updated article.

That matters because the two settings produce different Conversions totals for identical delivery. If accounts were migrated onto a 1-day view-through window, then reported conversions rise, reported CPA falls, and reported conversion rate rises — with no change whatsoever in campaign performance. If accounts start at 0 Day, nothing moves until someone changes it.

We are not going to guess which. Read your own Attribution windows setting under Edit columns before you compare this week to last week.

What this actually breaks

Any week-over-week comparison that spans 2026-09-16. If your view-through window is (or becomes) 1 Day, a performance chart crossing this date shows a step change that is a definitional artifact, not a result. Annotate the date in whatever dashboard your team trusts.

Blended CPA math. If you compute CPA as spend ÷ conversions from the Ads Manager Conversions column, and that column now absorbs view-through, your CPA falls without anything improving. Note that OpenAI states billing and optimization are unchanged — so your actual cost per click-through conversion is exactly what it was. Only the numerator's denominator moved.

Cross-channel comparisons. A 1-day view-through window is a narrow one by industry standards. If you are benchmarking ChatGPT Ads against a Meta account running a 1-day-view/7-day-click setup, the view-through components are now roughly comparable in kind — but if your Meta account runs a longer view window, ChatGPT Ads will still under-report by comparison. The windows are selectable now, which means they are also mismatched now unless someone deliberately aligns them.

Anything reading the API. Per the developer docs' current wording, an API consumer should still expect click-through-only Conversions. Per the help centre, the UI may not agree. If you reconcile API pulls against Ads Manager screenshots, expect a discrepancy and do not assume one side is broken.

What else moved in the same update

Three smaller documented changes shipped alongside, all verified 2026-09-16:

• View-through reporting levels. View-through conversions are documented at the campaign, ad group, and ad levels when the window is 1 Day, and there is now an optional standalone View-through conversions column, plus an attribution breakdown on hover over the Conversions column.
• Conversion-time reporting. Conversions uses ad event time by default — the time of the click or impression that got credit. A new Conversions (by conv. time) column reports on when the conversion actually happened. For any campaign with a long consideration window, these two columns will not match, and the conversion-time view is the one that answers "did last week's spend work".
• Segment breakdowns. The Segment menu now controls Device, Country, and Platform breakdowns; it previously controlled Device and Country. It still does not add conversion-event columns.

Separately, the Billing & Payment article was updated the same day to describe the Conversions objective's two billing methods (oCPC click billing and oCPM impression billing) alongside CPM and CPC, and to state that ads are not billed per conversion. It also softened the card authorization hold language: the previous text named a temporary "$50 or $100" hold released within 7 days; it now describes a temporary hold without naming an amount and says it may remain visible for up to 8 days. We covered the objective model change itself in ChatGPT Ads adds oCPM.

What to do this week

1. Read your Attribution windows setting in Edit columns, for each account. Do not assume. Write the value down.
2. Annotate 2026-09-16 in your reporting so the step change is legible to whoever reads the chart in three months.
3. Add the standalone View-through conversions column. Whatever the headline total does, you want the split visible, because the split is what tells you whether a change is real.
4. Decide your window deliberately, and align it across channels. The point of a selectable window is that you choose it. A 30-day click / 0-day view setup and a 7-day click / 1-day view setup will tell you two different stories about the same campaign.
5. If you pull the API, reconcile once by hand against Ads Manager before trusting either for a budget decision, given the current documentation conflict.

Sources

All verified 2026-09-16:

• Measure Results — help centre; flexible attribution windows, the Conversions total definition, view-through reporting levels, conversion-time reporting, Segment breakdowns.
• Billing & Payment — help centre; Conversions objective billing methods, authorization hold wording.
• Conversion Measurement — help centre.
• Measurement Pixel — developer documentation; the unchanged "not included in Conversions" wording.
• Conversions API — developer documentation; same unchanged wording.

Previous wording quoted above is from our own dated captures of the same URLs taken on 2026-09-15, one day before the change.

Soku tracks OpenAI's ChatGPT Ads documentation surfaces daily and dates every factual claim to the capture that supports it. Analysis and operational recommendations in this article are Soku's own; the quoted wording is OpenAI's.