The Core Difference
| Metric | Full form | Question it answers | Use this tool |
|---|---|---|---|
| CPM | Cost per thousand impressions | How much does it cost to buy 1,000 impressions? | CPM calculator |
| RPM | Revenue per thousand pageviews | How much revenue does a publisher earn per 1,000 pageviews? | RPM calculator |
Example
If an advertiser pays $500 for 100,000 impressions, the CPM is $5. If a publisher earns $350 from 100,000 pageviews, the RPM is $3.50. The difference matters because ad buying cost and publisher revenue are not always the same.
How This Supports Website Revenue Estimates
Use RPM when estimating how much a website can earn from its traffic. Use CPM when pricing campaigns or sponsorship inventory. For a broad traffic and income estimate, start with the website traffic and income calculator.