CPM formulas
CPM = Cost ÷ Impressions × 1,000
Cost = CPM × Impressions ÷ 1,000
Impressions = Cost ÷ CPM × 1,000
Cost = CPM × Impressions ÷ 1,000
Impressions = Cost ÷ CPM × 1,000
Example: A campaign costs $500 and delivers 100,000 impressions. The CPM is $5.00. If it got 800 clicks, the CTR is 0.8% and the cost per click $0.63.
Lowering your CPM
- Broaden targeting slightly — very narrow audiences are more expensive.
- Refresh creative: ads with higher engagement are often rewarded with cheaper delivery.
- Avoid peak seasons (Q4) for awareness campaigns when possible.
Measure what the spend brings back with the ROAS calculator.
Frequently asked questions
What does CPM mean?
CPM stands for cost per mille — the cost of 1,000 ad impressions. CPM = cost ÷ impressions × 1,000.
What is a good CPM?
It varies widely by platform, audience and season. Broad display ads can cost a few dollars per thousand, while targeted social or connected-TV campaigns often cost $10–$30 or more. Compare against your own past campaigns.
How is CPM different from CPC?
CPM charges for views; CPC (cost per click) charges only when someone clicks. CPC = CPM ÷ (CTR × 1,000).
How do publishers use CPM?
For publishers, RPM (revenue per 1,000 page views) is the mirror image — it shows how much a site earns per thousand views.