Monetisation & Revenue
Cost Per Mille
Also called: CPM, cost per thousand impressions, cost per 1000
CPM is an advertiser-side price that creators borrow because Studio reports it. The number moves with who is watching, what the subject is and how hard advertisers are competing for that audience, so a finance channel and a gaming channel with identical view counts can show wildly different figures.
RPM describes your money instead. CPM counts advertiser spend on monetised impressions before YouTube takes its share, while RPM divides everything you earned, ads plus memberships plus Premium and the rest, across every view a video got. A healthy CPM sitting next to a weak RPM usually means most of those views never carried an ad.