CPM Calculator
(Cost Per Thousand Impressions Tool)
Work out CPM, the cost per thousand impressions, from ad spend and impressions. Switch modes to find the budget for an impression goal or the impressions a budget will buy.
Step 1 — Calculation Goal
Step 2 — Core Metrics
The total cost of your marketing campaign
Number of times your ad was seen
CPM Result
💡 CPM Formula Guide
This CPM calculator works out the cost per thousand impressions of an ad campaign. Enter any two of ad spend, impressions and CPM and it gives the third, so it also answers how much budget an impression goal needs and how many impressions a budget will buy. CPM, short for cost per mille, is the standard way display, video and social ad space is priced.
How to Calculate CPM
CPM is the ad cost divided by impressions, multiplied by 1,000.
A campaign that cost $500 and was shown 125,000 times has a CPM of $500 ÷ 125,000 × 1,000 = $4.00. Every thousand times the ad appeared cost four dollars.
The same three numbers rearrange to give the other two answers:
| To find | Formula | Example |
|---|---|---|
| CPM | Cost ÷ Impressions × 1,000 | $500 ÷ 125,000 × 1,000 = $4.00 |
| Ad cost | CPM × Impressions ÷ 1,000 | $4 × 500,000 ÷ 1,000 = $2,000 |
| Impressions | Cost ÷ CPM × 1,000 | $2,000 ÷ $4 × 1,000 = 500,000 |
The M in CPM is the Roman numeral for a thousand, from the Latin mille. That is why the metric is also called cost per thousand, and why the result is always multiplied by 1,000.
Impressions Are Not Reach
CPM is calculated from impressions, the number of times the ad was shown. Reach is the number of different people who saw it. If 50,000 people each saw an ad 2.5 times on average, that is 125,000 impressions, and the CPM uses the larger number. Ad platforms report both, so check that the figure you enter is impressions. Dividing by reach instead gives a cost per thousand people, which is higher whenever people saw the ad more than once.
From CPM to Cost Per Click
A CPM says what it costs to be seen. What it costs to get a visit depends on the click-through rate.
At a $4 CPM and a 1% click-through rate, 1,000 impressions bring 10 clicks, so each click costs $4 ÷ 10 = $0.40. Double the CTR to 2% and the same $4 buys 20 clicks at $0.20. This is why a low CPM is not automatically a good deal: an audience that never clicks is expensive at any price. Enter a CTR in the calculator's traffic settings to see clicks and CPC, or work from the other direction with the CTR Calculator and the CPC Calculator.
What Is a Good CPM?
There is no single reliable benchmark, because CPM depends on the platform, the country, the audience, the ad format and the time of year.
Published figures show how wide the spread is. For Meta ads in 2025, one study of about 5,200 ad accounts by Vaizle reported an average CPM of $5.97, while Triple Whale, whose data comes mostly from ecommerce brands, reported a median of $13.48. Both can be accurate for the accounts they measured. Costs also rise in the fourth quarter, when holiday advertisers compete for the same impressions.
The useful comparison is with your own history. Track CPM by campaign and by month, and judge it together with click-through rate and conversion rate. A cheap CPM that reaches the wrong audience costs more per sale than an expensive one that reaches buyers.
CPM, CPC and CPA: Three Ways to Pay for Ads
| Model | You pay for | Usual purpose |
|---|---|---|
| CPM | Every 1,000 times the ad is shown | Awareness and reach |
| CPC | Each click | Traffic |
| CPA | Each sale, lead or sign-up | Conversions |
Whichever way a campaign is billed, all three can be calculated afterwards from spend, impressions, clicks and conversions, which makes them useful for comparing campaigns that were bought differently. The CPA Calculator covers cost per conversion. Publishers looking at what their own pages earn per thousand views want the eCPM Calculator.
How to Use the CPM Calculator
- Choose what to solve for: Pick CPM to price a campaign that has run, the ad budget needed for a number of impressions, or the impressions a budget will buy.
- Enter the two known values: Type in two of ad spend, impressions and CPM. The third is calculated as you type.
- Add a click-through rate: Optional. With a CTR the calculator estimates clicks and the cost per click that the CPM works out to.
- Add conversion details: Optional. Conversion rate, order value and unit cost extend the estimate to sales, revenue and profit.
Frequently Asked Questions
What does CPM stand for?
Cost per mille. Mille is Latin for thousand, so CPM is the cost of 1,000 ad impressions. It is also written as cost per thousand or CPT, and in German-speaking markets as TKP, the thousand-contact price.
How do I calculate CPM?
Divide the ad cost by the number of impressions and multiply by 1,000. A campaign that cost $500 and was shown 125,000 times has a CPM of $500 ÷ 125,000 × 1,000 = $4.00.
How many impressions will my budget buy?
Divide the budget by the CPM and multiply by 1,000. At a $4 CPM, $2,000 buys $2,000 ÷ $4 × 1,000 = 500,000 impressions. Switch the calculator to Impressions to do this directly.
What is the difference between CPM and eCPM?
CPM is what an advertiser pays for 1,000 impressions. eCPM, or effective CPM, is what a publisher earns per 1,000 impressions across all the ads shown, whatever way they were sold. The formula has the same shape, with earnings in place of cost.
Is CPM based on impressions or reach?
Impressions. An impression is counted each time the ad is shown, so one person who sees it three times counts as three. Reach counts that person once. Dividing cost by reach gives cost per thousand people reached, which is a different and higher figure.
Why does my CPM keep rising?
The usual causes are more advertisers bidding for the same audience, a narrower target audience, and the time of year, with the fourth quarter the most expensive. A high frequency also pushes it up, because the platform has to keep showing the ad to people who have already ignored it.