CPM

CPM stands for cost per mille, from the Latin for thousand. It is the price of 1,000 ad impressions. If a campaign spends 50 and earns 5,000 impressions, the CPM is 10.

CPM depends on how much competition there is for an audience. It is usually higher:

• in rich markets such as the United States, the United Kingdom and Australia
• in busy shopping seasons, especially the weeks around Black Friday and the end of the year
• for audiences many advertisers want, such as older buyers with high spending power
• when an ad's quality or engagement is poor, since platforms favour ads people respond to

CPM is a big input to whether ads can be profitable. A product with a thin margin may work at a low CPM and fail when CPMs rise in November.

The real CPM an advertiser pays depends on its account, targeting and creative, none of which is public. That is why any outside figure for a competitor's ad spend, including the spend shown in RivalSonar's ad library, is an estimate.