Cost cap: predictable ceiling
Keeps average CPA at or below target. Use when unit economics demand a hard ceiling, with enough creative diversity to find wins.
Bid cap: maximum efficiency
Very low bid cap delivers lowest-cost traffic but also lowest volume. Use only when volume isn't the bottleneck.
Default to cost cap
For most DTC and B2B accounts, cost cap is the pragmatic choice. Bid cap is an advanced lever for specific situations.