CPM, eCPM and page RPM describe amounts per thousand, but the amount and denominator must match the question. CPM expresses cost per thousand impressions. For the publisher calculations here, eCPM uses advertising revenue and ad impressions, while page RPM uses revenue and page views.
Write the units before calculating
| Metric used here | Calculation | Input to verify |
|---|---|---|
| CPM | Cost ÷ impressions × 1,000 | Advertising cost and corresponding impressions |
| Publisher eCPM | Revenue ÷ ad impressions × 1,000 | Revenue scope and matching ad-impression count |
| Page RPM | Revenue ÷ page views × 1,000 | Page views, not ad impressions |
Google defines CPM in terms of cost per thousand impressions. Its page RPM reference uses earnings and page views. Platform reports can qualify a rate with another denominator, so read the full metric name.
One fictional publisher report
Assume a report contains $120 revenue, 40,000 ad impressions and 10,000 page views for exactly the same scope. These invented inputs illustrate arithmetic; they are not a revenue benchmark.
- Publisher eCPM = 120 ÷ 40,000 × 1,000 = $3.
- Page RPM = 120 ÷ 10,000 × 1,000 = $12.
Neither result changes the $120 total. The rates differ because the denominators differ. It would be incorrect to describe $12 page RPM as $12 per thousand ad impressions.
Do not confuse a purchase rate with realized revenue
A separate campaign might cost $200 for 50,000 impressions, producing a $4 CPM. That figure cannot be reconciled with the fictional publisher report merely because both involve advertising. First establish whether the two reports concern the same inventory, period, currency and revenue treatment.
Use the appropriate calculator
Use the CPM calculator for campaign cost and impression questions, the eCPM calculator for realized revenue per ad-impression count, and the page RPM calculator for page-view-based earnings. For projections, the ad revenue calculator uses assumptions rather than retrieving account earnings.
A quick reconciliation checklist
- Choose the same date range and time zone.
- Check whether revenue is estimated, finalized, gross or net.
- Confirm the denominator and any inventory filters.
- Use one currency; the calculators do not convert exchange rates.
- Recalculate the total from the rate and matching count before drawing a performance conclusion.
Is a higher page RPM always better?
A rate alone is incomplete. A higher rate with far fewer page views can still produce less total revenue. Compare the rate, denominator and total together.
Can one “average CPM” predict all future earnings?
No. A scenario uses assumptions. Keep its output separate from observed results and revise the assumptions when real inputs change.
Official references
References checked: 26 October 2026. Examples identified as fictional are teaching inputs, not performance benchmarks.