Total media cost divided by the number of conversions, where a conversion is whatever the advertiser defined: a purchase, a lead, an install, a booked call. CPA is both a reported metric and a bidding model. When bought on CPA, the platform or network accepts the performance risk and the advertiser pays only for results, which is why true CPA deals are scarce and why the platform version, target CPA bidding, still bills on impressions or clicks and merely aims for the target.
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Cite this entry:
Agency Echelon. "CPA." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/cpa/