Guide
What is CPM?
CPM — cost per mille — is the price of 1,000 ad impressions. Here's what it means, how to calculate it, and how to read it next to the metrics that measure results.
CPM meaning
CPM stands for cost per mille, from the Latin mille, "thousand". It is the amount an advertiser pays for an ad to be shown 1,000 times. Each showing is an impression, whether or not anyone notices or clicks the ad.
Pricing per thousand dates back to print and broadcast advertising, where it let buyers compare a newspaper page with a radio spot on equal terms. Digital advertising kept the convention: display banners, social feeds, online video and connected TV are still bought and compared on CPM.
The CPM formula
CPM = total cost ÷ impressions × 1,000
Cost per single impression is simply total cost ÷ impressions; CPM scales that up to a thousand so the number is easy to read.
| Example | Cost | Impressions | CPM |
|---|---|---|---|
| Social campaign | $1,200 | 300,000 | $4.00 |
| Video pre-roll | $3,000 | 150,000 | $20.00 |
| Newsletter sponsorship | $800 | 40,000 | $20.00 |
Prefer not to do it by hand? The CPM calculator solves for CPM, cost or impressions and shows the working.
What affects CPM
- Who you target. The more advertisers want an audience, the more it costs to reach.
- Where the ad runs. Premium sites, video and connected TV usually carry higher CPMs than standard display.
- When it runs. Competition — and prices — rise around holidays and the end of the year.
- How good the ad is. Auction platforms reward ads people engage with by showing them for less.
CPM vs CPC vs CPA
CPM prices exposure. CPC prices a visit and CPA prices a result. They connect through two rates: click-through rate turns impressions into clicks, and conversion rate turns clicks into customers. A low CPM is only a bargain if those rates hold up.
CPM on YouTube and for publishers
For creators and publishers the same idea runs in reverse. CPM is what advertisers pay per 1,000 ad impressions on your content. RPM (revenue per mille) is what you actually earn per 1,000 views, after the platform's share and including views that showed no ads. eCPM is a publisher's effective CPM — earnings ÷ impressions × 1,000 — used to compare ad formats and networks.
Frequently asked questions
What does CPM mean in marketing?
Cost per mille: the price of 1,000 ad impressions. It is how most display, video and social media advertising is priced.
Why is CPM "per thousand"?
A single impression costs a fraction of a cent, which is awkward to quote. Pricing per thousand gives readable numbers like $4.50 — a convention inherited from print advertising.
What is the cost per impression formula?
Cost per impression = total cost ÷ impressions. Multiply by 1,000 and you have CPM.
Does CPM mean anything else?
Yes, outside advertising. In trucking it usually means cost per mile, in project management the critical path method, and in radiation measurement counts per minute. This page is about advertising.