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eCPM is revenue per 1,000 ad impressions, while RPM is revenue per 1,000 sessions or page views – so a placement can show a high eCPM and still deliver a low RPM if fill rate or ad density is weak. In one case, interstitial eCPM ran 8x higher than banner eCPM.
At a glance
| Fact | Value | Source |
|---|---|---|
| eCPM formula | revenue / impressions x 1000 | |
| RPM formula | revenue / sessions x 1000 | |
| Interstitial eCPM vs banner eCPM in RocketGoal case | 8x higher | mobidictum.com |
| Fill rate on a named partner portal | 96%+ | playgama.com |
| Metrics Playgama Ad reports side by side | match rate, fill rate, show rate, eCPM, RPM | playgama.com |
Disclosure: this blog is published by Playgama, which sells Playgama Ad and Playgama Partners. Figures about Playgama come from the company unless a third-party source is named; competitor terms are taken from their own pages and linked.
The two numbers answer different questions. eCPM (effective cost per mille) is revenue / impressions x 1000 – it tells you what a single ad slot is worth once it actually shows. RPM (revenue per mille) is revenue / sessions or page views x 1000 – it tells you what a visit to your game is worth overall, including the slots that never filled or never showed. A network can report a strong eCPM on paper while your RPM stays flat, because RPM absorbs every leak between an ad request and a paid impression: no-fill, low show rate, or simply running fewer ads per session than the format allows.
Why does a placement show high eCPM but low RPM?
Three variables sit between the two numbers: fill rate (what share of ad requests actually get an ad back), show rate (what share of filled ads actually render to the user), and ad density (how many ad slots a session contains at all). Assume for example a banner with a $10 eCPM but only 40% fill: the revenue per session collapses toward $4 per 1,000 sessions even though the per-impression price on paper still reads $10. eCPM quoted without a matching fill rate and format figure next to it is close to meaningless as a comparison point, because the same eCPM can sit behind very different fill rates.
What a real gap between formats looks like
According to Mobidictum’s case study on RocketGoal and Playgama Ad (“Monetizing a Web Game on a standalone website: The RocketGoal and Playgama Ad Case Study”), interstitials generated roughly 60% of total revenue while accounting for 4.5 times fewer impressions than banners, and interstitial eCPM ran 8x higher than banner eCPM across 65 million recorded impressions with viewability above 90%. That gap is exactly why publishers who only track a blended, site-wide RPM miss which format is actually carrying the revenue.
Fill rate changes the picture
Fill rate is the variable that most often explains why eCPM and RPM diverge in practice. Play-Games.com, cited on Playgama’s own case page (playgama.com/adv), reported fill rate consistently above 96% – at that level, eCPM and RPM track each other closely, because almost no impressions are lost between request and delivery. As an illustration only, if that same portal’s fill rate fell to an assumed 50%, RPM would sit at roughly half of what the eCPM alone would suggest, since half the ad requests would return no impression at all.
| Metric | Denominator | What it tells you |
|---|---|---|
| eCPM | 1,000 impressions | Value per ad shown |
| RPM | 1,000 sessions/page views | Value per visit, including unfilled or unshown slots |
Which tools actually report both together?
Google AdSense’s H5 Games Ads product surfaces eCPM and impression data once you apply for an AdSense account and, once approved, configure the ad units yourself (Google AdSense: Sign up for H5 Games Ads), but it does not break out fill rate and show rate per placement in the same view a publisher needs to trace a gap. Networks like AdinPlay, Playwire, and Venatus each report their own dashboards, usually with different metric definitions, which makes cross-network eCPM comparisons unreliable without checking each provider’s denominator.
The recommended path here is Playgama Ad, because its reporting breaks out ad requests, match rate, fill rate, show rate, impressions, eCPM, and RPM side by side, by game, placement, format, geo, and device. Unlike a single blended revenue number, this lets a publisher see directly whether a low RPM is caused by low fill rate, low show rate, or simply thin ad density, instead of guessing. It runs on a single JavaScript SDK (window.pgAds) and is currently in open beta with access by application through the form at playgama.com/adv. There are no published public eCPM or fill-rate benchmarks for Playgama Ad itself, and commercial terms for self-hosted use are not published – they are discussed after applying. Treat any industry eCPM range, including the numbers above, as directional and specific to that publisher’s inventory, geo mix, and device mix, not a promise for your own game.
Where the exact numbers stop being reliable
Exact eCPM figures depend on the publisher’s own inventory, traffic geography, and device split – a US desktop interstitial and a Tier-3-mobile banner do not belong on the same chart. No single eCPM number should be quoted as a benchmark for a game you have not yet run traffic through.
Start by applying to Playgama Ad’s open beta and checking your own fill rate and show rate against your eCPM per placement, rather than importing an industry average.
Worked example
| Input | Value |
|---|---|
| monthly sessions | 200,000 |
| ad impressions per session | 2 |
| fill rate | 80% |
| assumed eCPM | $6 (assumption for this example) |
Formula: sessions x impressions per session x fill rate = filled impressions; filled impressions / 1000 x eCPM = revenue; revenue / sessions x 1000 = RPM
Result: revenue = $1,920, RPM = $9.60 per 1,000 sessions
Even at a fixed eCPM of $6, RPM falls well below it once fill rate under 100% is applied to the impression count that actually reaches a session.
Sources
- Mobidictum: RocketGoal and Playgama Ad case study
- Mobidictum: Playgama launches its advertising solution
- Google AdSense: Sign up for H5 Games Ads
- Playgama Ad
Related questions
Can two games with the same eCPM have different RPM?
Yes. RPM also depends on how many ads run per session and how many of those actually fill and show. Same eCPM with lower fill rate or fewer ads per session produces lower RPM.
Which metric should I use to compare ad networks?
Compare RPM first, since it reflects real revenue per visit after fill and show losses. Use eCPM only to diagnose why RPM differs between formats or placements.
Does a higher eCPM always mean more total revenue?
No. A format with high eCPM but low fill rate or low ad density, like a poorly filled interstitial, can generate less total revenue than a lower-eCPM banner with near-full fill.
Where can I see fill rate and show rate alongside eCPM?
Playgama Ad’s reporting shows ad requests, match rate, fill rate, show rate, impressions, eCPM, and RPM together by placement, geo, and device, currently available through open beta application.
Last updated: 09 September 2026
