CPM (cost per mille)
Also called cost per thousand impressions, cost per mille, CPM
What is CPM?
CPM, or cost per mille, is the price an advertiser pays for 1,000 impressions of an ad. "Mille" is Latin for thousand. It is calculated as total spend divided by impressions, times 1,000. If you spend $50 and your ad is shown 10,000 times, your CPM is $5.
Some campaigns are billed by CPM, especially awareness and reach campaigns. Even when you pay per click or per result, CPM is still reported, because it shows how expensive it was to get in front of your audience.
CPM varies with the platform, the audience, the season and the ad's quality. Narrow or high-value audiences cost more, and prices usually climb around big shopping periods in the fourth quarter. Platforms also reward ads people engage with, so better creative can lower CPM.
Why CPM matters
CPM is the first link in the chain that ends in cost per sale. If CPM rises and nothing else changes, every customer costs more. Watching it helps you tell whether a campaign got worse because of the auction or because of your ad.
It is also the fairest way to compare the cost of attention between platforms and audiences before looking at clicks and sales.
How to calculate CPM
Divide total ad spend by the number of impressions, then multiply by 1,000. To lower CPM, broaden the audience, improve the creative so people engage, avoid the most competitive dates if you can, and test placements.
CPM example
CPM = (ad spend / impressions) × 1,000
$120 spend / 30,000 impressions × 1,000 = $4.00 CPMCPM FAQ
What does CPM stand for?
Cost per mille, meaning cost per thousand impressions. "Mille" is Latin for thousand.
What is a good CPM?
It depends on the platform, country, audience and time of year, so there is no single number. Compare your CPM against your own past campaigns and judge it alongside CPC and CPA, not alone.
Is a low CPM always better?
No. Cheap impressions to the wrong people are wasted. A higher CPM to a well-matched audience can still give a lower cost per sale.
Related terms
CPC, or cost per click, is what you pay on average each time someone clicks your ad. It equals ad spend divided by the number of clicks.
CPA, or cost per acquisition, is what you pay in ads for each conversion, such as a sale, sign-up or lead. It equals spend divided by conversions.
Impressions are the total number of times content was shown on screen, counting repeat views by the same person. Reach counts people.
Reach is the number of unique people who saw a post or ad at least once. Impressions count every view, including repeats.
ROAS, or return on ad spend, is the revenue earned for each dollar spent on ads. A ROAS of 4 means $4 in sales for every $1 of ad spend.
Paid social is advertising on social platforms like Instagram, TikTok, Facebook and LinkedIn, where you pay to show posts to a chosen audience.