How to use the effective CPM (eCPM) calculator
eCPM is the money you actually earned per 1,000 ad impressions. The formula is ad revenue ÷ impressions × 1,000, where 1,000 is the constant built into every CPM-family metric. It is the number the supply side watches: publishers, app developers and creators who own the ad slots.
It runs in the opposite direction from the CPM calculator. CPM is what an advertiser spends to buy 1,000 impressions; eCPM is what the slot owner earns from those same 1,000 impressions. The units look identical, which is why the two get mixed up: rising CPM hurts the buyer, while rising eCPM helps the publisher.
The "effective" part means revenue is converted back to an impression basis even when the underlying deal was priced per click or per action. That lets you line up networks and placements with different pricing models side by side. Enter expected monthly impressions and the tool multiplies the eCPM shown on screen to estimate monthly revenue. A reasonable eCPM level varies widely by placement, country, season and ad format, so no benchmark is suggested here.
Frequently asked questions
The denominators differ. eCPM divides by ad impressions, while page RPM usually divides by pageviews. If a page carries several ad units, the two numbers drift apart.
Not on the number alone. Compare the trend for the same placement over time or against an eCPM target you set, and check that adding units or moving them does not hurt the user experience.