What eCPM means
eCPM (effective cost per mille) is the estimated earnings for every 1,000 ad impressions. It rolls up all ad formats and pricing models — including impression-based and click-based ads — into one comparable number. The formula is simple:
eCPM = (earnings ÷ impressions) × 1000
And to project revenue from traffic:
revenue = impressions × eCPM ÷ 1000
where impressions = DAU × impressions per user × fill rate.
A realistic word of caution
These figures are planning estimates, not guarantees. Real eCPM swings widely with the user's country, the ad format (rewarded and interstitial usually pay more than banners), seasonality (Q4 is higher), fill rate, and mediation setup. Traffic from the US and Western Europe typically earns several times more per impression than traffic from many other regions. Treat the output as a range, and validate against your actual AdMob reports.
Tips to raise eCPM
- Use higher-value formats (rewarded, native, interstitial) where they fit the experience.
- Add mediation so multiple networks compete for each impression.
- Keep fill rate high and place ads where they are actually viewable.
- Segment by geography — the same app can have very different eCPM per country.
FAQ
What's the difference between eCPM and RPM?
They are calculated the same way — earnings per 1,000 units — but RPM (page/session RPM) is often used for web/pages, while eCPM is the standard term for ad impressions in apps.
Is fill rate the same as impressions?
No. Fill rate is the share of ad requests that actually return an ad. If you request 5,000 ads and 4,500 are filled, the fill rate is 90%. Only filled ads become impressions.
Why is my real revenue different from this estimate?
Because eCPM is not fixed. It changes daily with demand, geography, format and season. Use your own recent eCPM from AdMob for the closest projection.
Does this tool send my numbers anywhere?
No. All math runs locally in your browser and nothing is uploaded.