The cost of the next conversion, as opposed to the average cost of all conversions to date. Marginal CPA rises as spend increases within a channel, and the right budget is where marginal CPA reaches the value of a conversion, not where average CPA does.
Related terms
Cite this entry:
Agency Echelon. "Marginal CPA." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/marginal-cpa/