ChatGPT Ads swaps Max Bid and Max CPC for Target CPA and Target CPC average cost goals

ChatGPT's ad platform is replacing two manual caps, the maximum bid (Max Bid) and the maximum cost per click (Max CPC), with average cost targets. Since November 9, advertisers who create a conversion campaign in Ads Manager get Target CPA instead of Max Bid, and those who create a click campaign can use Target CPC.

The change shows up on an OpenAI help page about bidding and pricing that the company has updated, according to Search Engine Journal, which reported it on November 10. The old caps stop applying to existing campaigns on January 1, 2027.

An average goal instead of a ceiling

According to OpenAI's page, both new options are average cost targets, with no limit on any individual bid. Target CPA is the average an advertiser wants to spend per conversion, such as a purchase or a lead, and Target CPC is the average per click. A single click or conversion can cost more or less than the target, and the final average can also land above or below it.

“While Max CPC caps every bid, Target CPC lets our system bid above or below your target in individual auctions, aiming to deliver as many clicks as possible with your budget while working toward your desired average CPC,” OpenAI's bidding page says.

The page warns that a target set below recent performance can restrict delivery. In its example, $400 in spend and 10 attributed purchases produce an actual CPA of $40, and setting a $20 Target CPA does not guarantee purchases at that cost. A campaign can also underspend its budget when the target is too restrictive or conversion data is weak.

The bid target and the billing event are separate settings: a Target CPA campaign can be optimized for conversions and billed per click or per impression, depending on the billing mode. Across all strategies, including campaigns using Max Bid and Max CPC, the same rule applies: the final winning bid in the auction sets the price paid.

The API changes on November 18

API partners will get dedicated Target CPA and Target CPC fields, with no date announced yet. Starting November 18, a Max Bid or Max CPC value sent through the old fields to create a campaign or change an ad group's bid type will be treated as an average target, with no ceiling function. The old fields stay active through the end of December and are shut off on January 1, 2027.

Some OpenAI pages have not caught up with the switch. The basic advertiser page still says the maximum bid is set at the ad group level and recommends starting CPC campaigns at $3 to $5 per click. OpenAI also does not say what target a campaign still running on Max Bid or Max CPC will get once the caps go away.

The move mirrors Microsoft's, which as of October 1 stopped offering Max CPC on new non-portfolio campaigns using strategies such as Target CPA and Target ROAS. Microsoft's official rationale is that the cap can get in the way of its bidding systems' optimization.

What changes for advertisers

Advertisers on ChatGPT will no longer cap what they pay in each auction. Instead they set a budget and an average cost, and the automated system decides every bid. OpenAI suggests basing targets on recent actual average CPA or CPC and monitoring average cost while the campaign is learning. Those buying through API partners need to check which bid fields those tools use after November 18, and migrating before January 1, 2027 lets advertisers choose their target at the time of the switch.