Bid cap
A bid cap sets the maximum amount you'll pay per impression or click. Older Meta bid strategy that exposes more control than cost cap or target CPA.
What does Bid cap actually mean?
A bid cap (sometimes ‘bid limit’ or ‘maximum bid’) sets the highest amount you'll pay in any single auction. Meta and Google both expose bid caps as legacy bid strategies. The cap operates per impression for impression-bidding (CPM) or per click for click-bidding (CPC). That's different from cost cap, which operates on average CPA.
Bid cap gives the most direct auction-level control: the platform won't bid higher than your cap regardless of opportunity. The trade-off is missed scale: competitive auctions where higher bids would have been profitable are skipped. Most modern performance teams have moved away from bid caps in favor of cost cap or target CPA, which give the algorithm more flexibility while still respecting unit economics.
Bid cap remains useful for campaigns where impression-cost predictability matters (brand awareness, fixed-CPM contracts) more than conversion-volume optimization.
Example
A brand sets a $5 bid cap on a Meta CPM campaign. The platform won't pay more than $5 per 1,000 impressions in any auction. Competitive auctions where the winning bid is $7 are skipped, even if those impressions might have converted.
When it matters
Bid cap is for advertisers who need impression-cost predictability. For conversion-volume optimization, cost cap or target CPA outperform.
Related terms
Cost cap
Cost cap is a Meta bid strategy that limits maximum CPA. The platform spends as much as possible while keeping CPA at or below the cap.
Target CPA
Target CPA is a Smart Bidding strategy that aims to maximize conversions while keeping average cost per acquisition at your specified target.
CBO
CBO sets a single budget at the campaign level; Meta auto-distributes across ad sets based on real-time performance.
Smart Bidding
Smart Bidding is Google's family of automated, ML-driven bid strategies: Target CPA, Target ROAS, Maximize Conversions, Maximize Conversion Value.
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