ChatGPT Ads has few bidding levers, and some of them are one-way: a campaign's objective can't be changed once it's created. So this lesson is about deciding well before you build, rather than fixing things afterwards.
Three objectives, two ways to bill
In Ads Manager you choose between Views, Clicks and Conversions. OpenAI bills per impression or per valid click:
| Objective | What it optimises for | How it bills | What your bid means |
|---|---|---|---|
| Views | Impressions | Per impression (CPM) | Maximum per thousand impressions |
| Clicks | Clicks | Per valid click (CPC) | Maximum per click |
| Conversions | Conversions (oCPC) | Per valid click | Acts as a CPA bid to compete |
The confusing row is the last one. A Conversions campaign optimises towards the conversion, but doesn't bill per conversion: you pay for every valid click, whether it converts or not. The figure you enter is there to compete; it isn't the price of each conversion.
And note: the objective can't be changed afterwards, and neither can the chosen conversion event. Get it wrong and you need a new campaign.
Three strategies
| Strategy | Who sets the bid | Budget |
|---|---|---|
Fixed bid (fixed_bid) |
You: you set and adjust the maximum bid | Daily or lifetime |
Maximise clicks (maximize_clicks) |
OpenAI, with no maximum bid | Daily required |
Maximise conversions (maximize_conversions) |
OpenAI, with no maximum bid | Daily required |
With the two automated strategies, OpenAI adjusts bids to get the most out of the budget. With no maximum bid, your brakes are the daily budget and the account spend limit.
To optimise for conversions you need exactly one standard event active as the goal (custom events don't qualify) and enough volume. Measurement is covered in lesson 4 of this module.
The auction
OpenAI describes it as a second-price auction weighted by relevance: when several ads are eligible, both relevance and bid count. Two practical consequences:
- In a second-price auction, what you pay also depends on the bid of whoever comes behind you. With a fixed bid, your maximum is a ceiling, not a price tag.
- Relevance competes alongside the bid. Raising the bid won't fix an ad that doesn't fit the conversation: check hints, ad and landing page first (lessons 1 and 2).
"Bid too low": a warning, not a block
Ads Manager can show bid strength guidance, and warns separately when a group falls short. It is guidance, not a restriction: it doesn't block anything. And the other way round: if a campaign isn't serving, don't assume it's the bid. Ours wasn't serving with a sound bid and 8 approved ads; the reason was the account's brand review, still in progress (lesson 5).
Daily or lifetime budget
- Exactly one per campaign: daily or lifetime.
- A daily budget is required with maximise clicks and maximise conversions.
- A daily budget can't be turned into a lifetime one: you need a new campaign.
- A lifetime budget can't be lowered below what has already been spent.
- There is a daily minimum, and it is not published anywhere: your account sets it. See the detail a few lines below.
- The campaign budget and the account spend limit apply separately. The limit is set by period (dates and amount) and, once used up, it blocks delivery even if the campaign still has budget left. Accounts billed by invoice also have a daily account limit.
Don't raise the budget because today's report shows little spend: spend data arrives late, and a spend of 0 doesn't mean there are no charges (lesson 5).
The daily minimum is set by your account, and you won't find it written down
This is one of the things that baffles people most at the start, so it is worth telling it plainly: the platform requires a minimum daily budget that it does not publish, and it is not the same for everyone. What we measured in two real accounts on the same day:
| Account | Minimum it accepted |
|---|---|
| An account in dollars | 25 a day |
| An account in euros | 15 a day |
And two details that make it even more confusing, both of them verified:
- It does not depend on the objective. A Clicks campaign in the dollar account also required 25, even though 15 would have been enough in the other one.
- It is not the same figure converted: 25 dollars are not 15 euros, so it is not a single amount translated into each currency.
The most likely explanation is the account's currency, but it is not documented, so do not take it for granted either in your account or in a client's.
How to settle it without losing your morning: do not hunt for the figure, ask for it. Try to save the budget you want and, if it is below the minimum, the error itself will tell you the exact minimum for that account (something like "the daily budget must be at least …"). Write it down and move on. It is faster and more reliable than any table, because the table can change and your account is the one that decides.
⚠️ And the warning that really saves money: do that check before you build the structure, not after. If you leave the campaign created and the groups and the ads done, and the budget is rejected at the end, you are left with a campaign that cannot serve while you believe it is already running.
⚠️ Pitfall: the Views bid is set per impression, not per thousand. A $60 CPM equals $0.06 per impression. Enter 60 thinking of the CPM and you're bidding a thousand times what you meant.
Reference prices
OpenAI recommends starting CPC campaigns with a maximum bid of $3 to $5 per click. It publishes no reference prices for CPM, and the figures quoted in the press change fast: your best reference will be your own cost per result.
That is a dollar figure: if your account uses another currency, convert it. We have no data of our own to add yet: our campaign (Clicks objective, maximise clicks, $25 a day, Spain) has only just been approved.
Where to start
- Do you already measure a standard event reliably and in volume? If not, start with Clicks. Bidding for conversions without solid measurement means optimising towards a broken signal while paying for every click.
- Would you rather control price or volume? Price: fixed bid, starting within the $3-5 range OpenAI recommends. Volume within a budget: maximise clicks with a daily budget, which is what we chose.
- Only want visibility? Views: compare what you pay per thousand impressions with what those impressions bring you.
- Set an account spend limit, especially with automated strategies.
- Once conversions have volume, create a new Conversions campaign: the Clicks one can't be switched over.
💡 Ninja trick: install measurement from day one even if you start with Clicks (lesson 4). That way you'll know when you have the volume to move to Conversions, instead of guessing.
What to remember
- Views bills per impression (CPM); Clicks and Conversions bill per valid click.
- The objective and the conversion event can't be changed: new campaign.
- Maximise clicks and maximise conversions have no maximum bid and require a daily budget; your brakes are that budget and the account limit.
- The low-bid warning is guidance, not a block; and relevance competes alongside the bid.
- OpenAI recommends starting CPC at $3-5 per click.
- The minimum daily budget is set by your account and is not published: check it with one attempt before building anything.
- Views bids are set per impression: a $60 CPM is $0.06 per impression.