How the ChatGPT Ads Auction Works: Objectives, Bids and Budgets
By The InPromptAds Team 7 min read
Last verified 15 August 2026. Version 1.0. Next scheduled review 15 September 2026.
The mechanic, stated plainly. OpenAI uses a relevance-weighted, second-price auction to select among eligible ads, and states the system aims to maximise both advertiser and user value.
Two words in that sentence do most of the work, and a lot of published guidance treats this channel as though neither were there.
Second-price
You do not pay your bid. In a second-price auction the winner pays a price derived from the next competing bid rather than their own maximum, which means bidding your true maximum is not the same as spending it.
The practical consequence: your maximum bid is a ceiling, not a price. Advertisers who bid conservatively out of fear of overspending are, in a second-price system, mostly limiting their eligibility rather than protecting their budget.
Relevance-weighted
Selection is not bid order. Relevance is weighted into which ad wins, which means a more relevant ad can beat a higher bid.
This is where the channel's inputs connect. OpenAI documents that ad selection considers the context and intent of the conversation, the ad's landing page, its title and copy, and advertiser-provided context hints. Those same inputs feed relevance. So your landing page is an auction input, not just a destination.
An advertiser who raises bids to fix weak delivery, while pointing well-written ads at a vague landing page, is paying more to compensate for something the auction is scoring them down on.
Objectives, and what each one buys
ChatGPT Ads supports two buying models.
| Objective | Optimises for | You pay | You set |
|---|---|---|---|
| Reach | Impressions | Per 1,000 impressions (CPM) | Maximum CPM bid, at ad group level |
| Clicks | Clicks | Per valid click (CPC) | Maximum CPC bid, at ad group level |
OpenAI recommends starting CPC campaigns at a maximum bid of $3 to $5 USD per click.
A widely repeated claim that this channel is CPM-only, priced on views rather than clickthrough, traces to February 2026 pilot reporting. It described the pilot accurately and it does not describe the product now. If a guide tells you that you cannot buy clicks here, it is six months stale.
Bid-strength guidance
Ads Manager may provide bid-strength guidance indicating whether a bid is likely to be competitive or may limit delivery.
Worth knowing because it changes what "no delivery" means. In a channel with no published benchmarks, an in-product signal telling you a bid is uncompetitive is the closest thing to a benchmark you will get, and it is free. Read it before concluding the channel does not work for your category.
For product feed campaigns specifically, reported guidance is a recommended bid around 3 USD with bids below 2 USD receiving minimal traffic, which is consistent with the general CPC recommendation.
Budgets, and the floor underneath everything
Bids decide what you pay per unit. Budgets decide whether the campaign runs at all.
The minimum daily spend is 25 USD per campaign in the United States, with local equivalents: 15 GBP, 2,500 JPY, 25,000 KRW, 25 AUD, 25 CAD, 25 NZD, 40 BRL and 150 MXN.
The frequently repeated claim that ChatGPT ads have no minimum spend refers to the 200,000 USD entry commitment removed on 5 May 2026. That was an entry commitment. The campaign floor is a different thing and it still exists.
And the floor is not a test budget. At 25 USD a day, a two-week campaign is roughly 350 USD, which produces single-digit conversions for most advertisers and cannot separate a working channel from a broken one.
What this means for setup
Pick the objective that matches the decision you need to make. If you are testing whether the channel produces qualified traffic, Clicks with conversion measurement configured gives you a readable answer. Reach optimises for a metric you probably cannot act on yet.
Fix relevance before raising bids. Landing page, title and copy are all selection inputs. Raising a bid to solve a relevance problem is the expensive order of operations.
Treat the maximum bid as a ceiling. Second-price means the ceiling is not the expected cost.
Read bid-strength guidance as diagnostic. It is the only in-product competitiveness signal in a channel with no external benchmarks.
What we cannot tell you
How relevance is weighted against bid. OpenAI states the auction is relevance-weighted. It does not publish the weighting, and anyone stating a ratio is inventing it.
What clearing prices look like by category. Reported observations put clearing in the 25 to 45 USD CPM range in serving markets, and published ranges disagree. OpenAI states no benchmarks exist across advertisers, industries or campaign types.
What counts as a valid click. Clicks campaigns pay per valid click. The validity criteria are not published.
How bid-strength guidance is calculated. In-product signal, undocumented method.
Any of this from experience. We do not hold an advertiser account.
Quick answers
How does the ChatGPT ads auction work? OpenAI uses a relevance-weighted, second-price auction to select among eligible ads. Advertisers set a maximum bid at the ad group level and relevance is weighted into which ad is selected.
Do ChatGPT ads use CPM or CPC? Both. A Reach objective optimises for impressions and pays per 1,000 impressions. A Clicks objective optimises for clicks and pays per valid click.
What should my starting bid be on ChatGPT ads? OpenAI recommends starting CPC campaigns with a maximum bid of $3 to $5 USD per click. For product feed campaigns, reported guidance is around 3 USD, with bids below 2 USD receiving minimal traffic.
Do I pay my maximum bid on ChatGPT ads? No. It is a second-price auction, so the maximum bid is a ceiling rather than the expected price.
Why is my ChatGPT ad not delivering even with a high bid? The auction is relevance-weighted, so bid alone does not determine selection. Ad selection considers conversation context and intent, the landing page, the title and copy, and context hints. Ads Manager may also show bid-strength guidance indicating whether a bid may limit delivery.
What is the minimum budget for a ChatGPT ads campaign? 25 USD per day per campaign in the United States, with local equivalents including 15 GBP, 2,500 JPY, 25,000 KRW and 40 BRL. The 200,000 USD entry commitment was removed on 5 May 2026 and is a separate thing.
Sources
| Claim | Source | Tier |
|---|---|---|
| Relevance-weighted, second-price auction; aims to maximise advertiser and user value | OpenAI Help Center, Ads in ChatGPT: The Basics, updated ~8 Aug 2026 | Confirmed, primary |
| CPM and CPC buying via Reach and Clicks objectives | Same | Confirmed, primary |
| Maximum bid set at ad group level | Same | Confirmed, primary |
| Recommended starting CPC maximum bid of $3 to $5 USD | Same | Confirmed, primary |
| Bid-strength guidance may indicate competitiveness or delivery limits | Same | Confirmed, primary |
| Selection considers conversation context and intent, landing page, title, copy, context hints | Same | Confirmed, primary |
| Minimum daily spend by market | OpenAI advertiser documentation | Confirmed, primary |
| 200,000 USD entry commitment removed 5 May 2026 | OpenAI | Confirmed, primary |
| Feed campaign recommended bid ~3 USD; below 2 USD minimal traffic | GeekSeller, 15 June 2026 | Reported |
| Observed clearing 25 to 45 USD CPM | Trade press | Reported, ranges disagree |
| CPM-only, priced on views rather than clickthrough | eMarketer, 10 Feb 2026 | Reported, superseded by current documentation |
| No benchmarks across advertisers, industries or campaign types | OpenAI advertiser FAQ | Confirmed, primary |
Related reading
ChatGPT Ads Test Budget Calculator — turn the auction floor into a readable test budget.
ChatGPT ads context hints — the targeting input that feeds relevance
How to measure ChatGPT ads — what reporting includes, and what it does not
Changelog
15 August 2026. v1.0 published. Records that CPC buying is available, superseding February 2026 reporting describing the channel as CPM-only.
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The InPromptAds Team
Writes about AI-native advertising and the shift from search to conversation.
