Example result
CPM mode, cost 500, impressions 100,000
- CPM
- $5.00
- Formula
- ($500.00 / 100,000) x 1,000 = $5.00
Captured 2026-10-19.
How it works
- Pick what you want to find: CPM, total cost, impressions or eCPM.
- Fill in the two numbers that mode asks for. Commas and a dollar sign are fine.
- Read the result and the formula line under it, with your numbers substituted in.
The formulas
CPM = (cost / impressions) x 1,000. Total cost = (CPM x impressions) / 1,000. Impressions = (cost / CPM) x 1,000. eCPM = (revenue / impressions) x 1,000.
The M in CPM comes from the Latin mille, a thousand. A CPM is always a price per thousand impressions, never per impression.
CPM and eCPM are the same math from two sides
CPM is usually what an advertiser pays. eCPM, effective CPM, is what a publisher earns per thousand impressions once every source of revenue is added up, whatever way that revenue was priced. A publisher selling clicks or conversions can put them on one scale by turning total revenue into an eCPM.
Related metrics worth knowing
CPC, cost per click, is cost divided by clicks. CPA, cost per acquisition, is cost divided by conversions. CPM prices attention, CPC prices a visit, CPA prices an outcome, so the three only compare fairly when you look at the same campaign.
To move between them, multiply through the rates: a CPM of 5 dollars with a 1 percent click rate is a CPC of 0.50 dollars.
Why CPM varies
Most CPMs are set in an auction, so the price moves with how many advertisers want the same audience at the same moment. The main drivers are the audience and country you target, the ad format, the season of the year and the competition for that audience.
Because of that, two campaigns on the same platform can have very different CPMs. Use the figure from your own campaign reports, not a headline average.
Advertising cost formulas
| Metric | Formula | What it answers |
|---|---|---|
| CPM | (cost / impressions) x 1,000 | What each thousand impressions cost |
| eCPM | (revenue / impressions) x 1,000 | What each thousand impressions earned a publisher |
| CPC | cost / clicks | What each click cost |
| CPA | cost / conversions | What each sign-up or sale cost |
Sources
- Wikipedia: Cost per mille read 2026-10-19
This tool is run by LookValid. It is not connected to any agency, company or service named on this page.
Frequently asked questions
How do I know if my CPM is competitive?
No one figure suits every campaign, because audience, country, ad format, season and competing bidders all move it. Set it against your own earlier campaigns and against what a thousand impressions are worth to your business.
How does eCPM differ from CPM?
CPM is a price for each thousand impressions and normally describes what an advertiser pays. eCPM describes what a publisher earned for each thousand impressions, with every revenue source and pricing model folded in.
How is CPM calculated from a budget?
Find the cost of one impression and scale it up to a thousand. A budget of 500 dollars spread over 100,000 impressions comes to 5 dollars per thousand.
Can I find how many impressions a budget buys?
Yes. Use the impressions mode: divide your budget by the CPM, then multiply by 1,000.
Why does the calculator show nothing?
It shows a result only when both numbers are valid. A blank field, text, a negative number, or a zero for impressions or CPM leaves the result empty instead of showing a wrong figure.