RPM vs CPM

CPM is what advertisers pay per 1,000 ad impressions. RPM is what you keep per 1,000 views or pageviews. Mixing the two inflates the estimate.

What each word means

CPM (cost per mille) is what an advertiser pays for 1,000 ad impressions. An impression is an ad load, not a video view and not a pageview. A page can fire several impressions. A view can fire none.

RPM (revenue per mille) is what you keep per 1,000 units. On YouTube that unit is usually views. On a website it is usually pageviews (Page RPM) or ad impressions (Ad RPM). Always say which unit the RPM uses.

Take-home RPM already reflects fill rate, viewability, and the platform's cut. Advertiser CPM does not.

A worked example

Suppose advertisers pay a $12 CPM, 60% of pageviews fill an ad, there is one ad per page, and the network pays you 68%. Page RPM is 12 × 0.60 × 0.68 = $4.90. Quoting a $12 RPM because you saw a $12 CPM is how a $5,000 month becomes a $12,000 story.

YouTube's extra confusion

YouTube Studio shows both CPM and RPM. RPM is the one that matches the deposit. Watch Page ads pay creators 55% of net ad revenue. Shorts pay 45% of a pooled allocation. Neither figure is a rate per 1,000 views. If someone sells you a single YouTube RPM without a niche or a country mix, they are averaging incomparable channels.

Use the RPM calculator when you already have two of the three numbers. Use the YouTube or website calculators when you only have traffic and a niche.