Metrics · Channel · Acquisition · Daily · $ · Updated 2026-07-21

What is Cost Per Mille?

Short answer: The average cost to reach one thousand ad impressions.

Definition

The average cost to reach one thousand ad impressions.

Formula

(Total ad spend / Impressions) x 1000

How to measure

Divide total ad spend by total impressions delivered, then multiply by 1,000.

Why track it

CPM is used to compare raw reach efficiency between channels, independent of how well the creative converts once seen.

Example

A display campaign spending $300 for 150,000 impressions reports a $2.00 CPM.

FAQ

What is Cost Per Mille?
The average cost to reach one thousand ad impressions.
How do you calculate Cost Per Mille?
(Total ad spend / Impressions) x 1000
Why track Cost Per Mille?
CPM is used to compare raw reach efficiency between channels, independent of how well the creative converts once seen.
What is Cost Per Mille? Definition, formula, and growth use · Cofounderbase