CPM stands for cost per mille (Latin for thousand) and measures the cost to deliver 1,000 ad impressions: (total spend ÷ impressions) × 1,000. It is the dominant pricing model for awareness and reach campaigns.
Why it matters for agencies
Because it normalises cost to a fixed unit of delivery, CPM lets you compare the price of attention across placements with very different budgets and audience sizes. But CPM measures price, not quality — a low CPM against the wrong audience, or with poor viewability, is the most expensive media you can buy. Always read it next to a quality metric and the downstream conversion rate.
Run the numbers with the free CPM calculator.