Where you can set them
- Maximize clicks: a maximum CPC bid limit, on a standard or portfolio strategy. Google notes that bid adjustments apply on top of the limit. Demand Gen supports Maximize clicks but not maximum CPC bid limits.
- Target CPA and Target ROAS: maximum and minimum bid limits, on portfolio strategies only, not standard ones. Google says any limits you set are used in Search Network auctions only. For Target ROAS they're available on Search and Shopping portfolios, and Google's Target CPA page says they aren't available for display-only campaigns.
What Google says about setting them
On Maximize clicks, Google presents the limit as a cost control for when your CPCs are higher than you want, with a warning that limits set too low can stop the strategy reaching its goal. On Target CPA and Target ROAS, Google says setting bid limits isn't recommended, because they restrict automatic bid optimization and can prevent Google from bidding the amount that best meets your target. The minimum limit isn't a hard floor either: Google may set a bid below it, generally due to smart pricing.
What a tight cap cuts off
A maximum limit takes you out of every auction where the bid needed to win is above it. In our experience those are often the most competitive, highest-intent searches, so a tight cap shows up as lost impression share due to rank and fewer conversions, while cost per conversion looks fine. If cost per conversion is the worry, we would rather change the target than cap the bid. More in a low target CPA isn’t saving you money.
Common questions
Can I set a max CPC bid limit on Target CPA?
Only on a portfolio Target CPA strategy, not a standard one. Google doesn't recommend it, and says any limit you set is used in Search Network auctions only.
Does Maximize clicks have a max CPC bid limit?
Yes. You can set a maximum CPC bid limit to cap what Maximize clicks bids per click. Google notes bid adjustments apply on top of it, and a limit that is too low can stop the strategy reaching its goal.
Is the minimum bid limit a guaranteed floor?
No. Google says it may set a max CPC below your minimum bid limit, generally due to smart pricing, so the limit isn't the absolute lowest bid.
Why doesn't Google recommend bid limits with Smart Bidding?
Google says bid limits restrict its automatic bid optimization and can stop it from setting the bid that best meets your Target CPA or Target ROAS.
Do bid limits work in Display or Demand Gen campaigns?
Google says Target CPA and Target ROAS bid limits are used in Search Network auctions only and aren't available for display-only campaigns. Demand Gen supports Maximize clicks but not maximum CPC bid limits.