Page RPM, or revenue per 1000 page impressions, is Google AdSense’s default reporting metric. It is calculated by dividing your estimated earnings by the number of page views you received, then multiplying by 1000. Page RPM shows you the revenue by page of your website, while cpm is a metric per ad unit. As a rough rule, RPM will always be higher than cpm because its an aggregate of all ad units on a page.