"My CPM is $20, so I earn $20 per thousand views" — these are different numbers

"My CPM is $20, so I earn $20 per thousand views" — these are different numbers

Conflating CPM and RPM is one of the most common income-projection errors, and it inflates expected earnings by roughly half.

Context. CPM is what advertisers pay per thousand ad impressions. RPM is what the creator receives per thousand video views, after the platform's revenue share and after accounting for unmonetized views.

Findings. Two adjustments separate them. First, the platform share — commonly around 45% retained by YouTube on ads — means creators see a little over half of CPM. Second, not every view carries an ad: a substantial share of views are unmonetized, so RPM divides revenue across more views than CPM does. The net effect routinely makes RPM a fraction — often a third to a half — of the headline CPM creators quote.

Caveats. Exact ratios vary by ad fill rate, format mix, and audience geography; the figures above are typical, not universal. Platform-reported numbers also lag and net out differently by program.

Implication. Projecting income from CPM overstates earnings by the share-and-fill gap. Always model from RPM.

What we still don't know: fill-rate distributions are platform-internal, so the CPM-to-RPM ratio can't be predicted precisely in advance.