RPM (Revenue Per Mille)

RPM (revenue per mille) is the revenue a publisher earns for every one thousand ad impressions or page views, calculated as RPM = (total revenue ÷ impressions) × 1,000. It is the headline monetization metric for sites that run ads, telling a publisher how much each thousand views is worth.

RPM comes in two common forms. Page RPM divides revenue by page views (a page may carry several ad slots), while impression RPM divides by individual ad impressions. A $12 page RPM means a site earns $12 for every 1,000 pages served, blending all the ads on each page into one figure.

How it differs from CPM#

RPM and CPM (Cost Per Mille) describe the same thousand impressions from opposite sides of the marketplace. CPM is what an Advertiser pays per thousand; RPM is what the Publisher keeps per thousand after the ad network's fees and unfilled inventory are accounted for. A publisher's RPM is therefore always lower than the gross CPMs advertisers bid, because of revenue share, blank impressions, and house ads.

Why it matters#

RPM is the publisher's profitability gauge: it captures fill rate, bid density, and audience value in a single number, making it easy to compare pages, sections, or traffic sources. Raising RPM means earning more from the same traffic, through higher demand competition, better placements, or more engaged readers. Each unit of inventory it measures is one Ad Impression.

Related terms: CPM (Cost Per Mille), Publisher, and Ad Impression.