Both are auction-based advertising platforms, and that surface similarity leads a lot of media buyers to assume a Google Ads strategy transfers over with minor tweaks. It mostly doesn't. Here's what actually carries over, and what has to be rebuilt from scratch.
The gap shows up clearly in the numbers. Independent analysis from Similarweb puts average ChatGPT ads click-through rate at around 0.68%, against roughly 6.64% for Google Search, a category where a page of competing results and years of user habit both work against a single sponsored card. But ChatGPT ads convert at 4% to 7% for commercial categories, well above Google Search's roughly 2% to 4%. Same auction-style mechanic underneath. Very different funnel behavior on top of it.
Google Ads. Built on two decades of intent data
Google Ads works because two decades of search behavior gave it an enormous, granular signal set: keywords, demographics, in-market audiences, remarketing lists, and a bidding system tuned against all of it. A media buyer can target almost any slice of intent they can describe, and Google's own Quality Score has enough historical signal behind it that experienced buyers can predict it reasonably well before a campaign even launches.
ChatGPT Ads. Built on conversation context, not profile data
ChatGPT ads work differently by design. Targeting runs on the topic of a conversation, location, platform and uploaded audience lists, not demographic or interest data. Advertisers write "context hints," plain-language descriptions of the conversations where an ad is relevant, rather than bidding on exact-match or broad-match keywords. A Google Ads keyword list doesn't translate directly here, since a context hint describes a buyer's situation, not a search term. That's partly a privacy choice, since OpenAI doesn't hand advertisers access to what people are actually discussing, and partly a reflection of how new the ad product still is.
Both weight relevance into the auction, but ChatGPT weights it harder
Google Ads and ChatGPT ads both fold quality into the auction rather than ranking purely on bid. ChatGPT weights it more aggressively: OpenAI describes relevance as a multiplier on your bid, not a tiebreaker, meaning a $3 bid paired with tightly relevant creative can outrank a $7 bid with generic creative. Google's Quality Score works on a similar principle, but ChatGPT's version rests on a newer, less battle-tested signal set, context hints, ad copy, headline and landing page, so the "prediction muscle" experienced Google Ads buyers rely on doesn't transfer cleanly yet.
Where the auctions actually overlap
Both run a relevance-weighted, second-price auction where ad quality affects ranking alongside the bid, which means the fundamentals of a strong campaign, tight relevance between the ad and the context, and a genuinely good landing experience, transfer reasonably well. A media buyer's instinct for what makes a good ad isn't wasted here.
Where the playbook actually breaks
The parts that don't transfer are exactly the parts a Google Ads strategy leans on hardest: keyword-level targeting, audience segmentation by demographic or interest, and years of historical performance data to optimize against. Campaign structure is simpler too. Google Ads offers a wide menu of campaign types, Search, Performance Max, Shopping, Display, each with its own optimization logic built on years of conversion data. ChatGPT ads currently offer two bidding objectives, Reach (billed per thousand impressions) and Clicks (billed per valid click), a much narrower menu that reflects how early the platform still is.
Why you'll likely need both, not just one
Google Ads still owns high-intent, bottom-of-funnel search behavior in a way nothing has replaced yet. ChatGPT ads are reaching people earlier, inside a conversation where they're actively working through a decision, and converting well once they do click, which is a genuinely different moment to show up in. Treating one as a replacement for the other misreads what each is actually good at right now.
Google Ads answers a question someone already knew to ask. ChatGPT ads show up while someone is still figuring out what to ask. Those are different jobs, not competing versions of the same job.
For the mechanics of how ChatGPT ads actually work, see our full explainer.