Definition
Cost per mille is what you pay for 1,000 ad impressions.
Category: Paid media · Updated 1 Oct 2026 · BLITZ Campaign editorial
What drives CPM?
Competition for the audience, season, placement and ad quality. CPMs often rise during busy seasonal periods.
Should you optimise for CPM?
No, cheap impressions to the wrong people are expensive. Watch CPM as context, judge on cost per purchase.