CPM

CPM is Meta's baseline pricing unit: the amount billed for 1,000 impressions of an ad. It moves with auction competition, audience size, seasonality, and vertical, so a lead-gen account in a low-competition niche might see a $4 CPM while a Q4 ecommerce account in the US fights at $25+. Because most Meta bidding ultimately resolves to a cost-per-impression price in the auction, CPM is the metric that best reflects how expensive it is to reach an audience at any given moment.

At $100k+/mo spend, CPM trends are the earliest warning sign of audience fatigue or rising competition, often moving before CTR or CPA visibly break. Power Ads' desk reviews CPM by ad set daily against a 7-day rolling average, since a sudden spike usually means a new competitor entered the auction, the account triggered a learning phase reset, or the creative is being shown to a narrower, pricier audience segment.