CPM (cost per mille)
Also called: cost per thousand impressions
CPM is what you pay for 1,000 ad impressions.
Formula
CPM = ad spend ÷ impressions × 1,000
Example: $500 spent for 62,500 impressions is a CPM of $8.
CPM is set by the auction: competition for your audience, the time of year and how engaging the platform judges your ad to be. It usually rises in Q4. A better ad can lower CPM because platforms reward ads people watch, which is one reason creative quality affects cost and not just conversion.
Go deeper
Part of the Addy video ad glossary. Addy is an AI agent that writes, renders and posts short-form video ads.