Cost per thousand impressions (also known as "CPM", also known as "Cost per mille") is an advertising term that describes how much it will cost to deliver one thousand impressions from advertisers who see the advertising on displays in a market. CPM is calculated by dividing the total cost of an advertising campaign by (total number of impressions/1000). For example, assume an outdoor advertising campaign cost $10,000 and it delivered total Impressions = 5,000,000; the calculation for CPM would be $10,000/(5,000,000/1000) = $2 CPM
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