What does eCPM stand for?
The term eCPM stands for 'effective cost per mille' and is used to describe the ad revenue generated per 1,000 ad impressions. eCPM is used to compare ad monetization earnings across variables, such as ad network, ad unit, region, OS, location, and more. On the monetization side, eCPM is calculated by dividing your total advertising earnings by the total number of impressions your app served, then multiplying by 1,000.
eCPM = (total earnings/total impressions) x 1,000
On the user acquisition side, eCPM is calculated by multiplying IPM (the installs per one thousand ad impressions) by CPI (cost per install, or the bid). eCPM is an equally important metric for user acquisition managers, as it indicates their campaigns' buying power within an ad network. The higher the eCPM, the more scale and impressions the campaign is able to unlock.
eCPM = IPM * CPI
Follow this link to learn more about eCPM.