CPM Calculator: Cost Per Thousand Impressions
Use this CPM calculator to find cost per thousand impressions from ad spend and impressions, or solve for spend or impressions. Add clicks and it shows CTR and CPC too.
By Troopus · Updated: October 28, 2026
- 2 inputs
- CPM, CTR, CPC
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CPM calculator for cost per mille
More options: conversions and revenue
Simple arithmetic on the numbers you enter, for information only. Not financial or media-buying advice. Ad platforms may report and bill differently.
How do you use a cost per mille calculator to work out CPM?
To calculate CPM, divide your total ad cost by the number of impressions, then multiply by 1,000. If you spend $500 and your ad is shown 100,000 times, CPM = $500 / 100,000 x 1,000 = $5.00. CPM stands for cost per mille, which means cost per thousand impressions.
The formula is CPM = (ad cost / impressions) x 1,000. Wikipedia gives the same calculation with a worked example: $15,000 of advertising cost over 2,400,000 impressions is $0.00625 per impression, which becomes a CPM of $6.25. The calculator above does these steps as you type and starts with a $500 example so you can see a result right away.
| Ad spend | Impressions | Working | CPM |
|---|---|---|---|
| $500 | 100,000 | 500 / 100,000 x 1,000 | $5.00 |
| $1,200 | 400,000 | 1,200 / 400,000 x 1,000 | $3.00 |
| $15,000 | 2,400,000 | 15,000 / 2,400,000 x 1,000 | $6.25 |
How does a CPM calculator solve for ad spend or impressions?
Rearrange the same formula: ad spend = CPM x impressions / 1,000, and impressions = ad spend / CPM x 1,000. At an $8 CPM, 250,000 impressions cost $2,000. With a $2,000 budget at a $12 CPM, you can expect about 166,667 impressions. Use the mode switch above to solve for either.
Switch to "Find ad spend" when you know the CPM an ad platform quotes and the reach you want. Switch to "Find impressions" when you have a budget and a CPM and want to know how many times the ad could be shown. These are planning numbers: real delivery depends on the auction, targeting and the platform, so treat them as a rough guide and not a promise.
| Budget | CPM | Impressions |
|---|---|---|
| $1,000 | $5 | 200,000 |
| $1,000 | $10 | 100,000 |
| $2,000 | $12 | 166,667 |
| $5,000 | $20 | 250,000 |
CPM vs CPC: how are CPM, CPC and CTR related?
CTR is clicks divided by impressions, CPC is spend divided by clicks, and CPM is spend per 1,000 impressions, so CPM = CPC x CTR x 1,000. At a $5 CPM and a 1% click-through rate, each click costs $0.50. Enter clicks in the calculator above to see CTR and CPC for your campaign.
Google Ads Help defines click-through rate as clicks divided by impressions, and average cost per click as the total cost of your clicks divided by the number of clicks. Put together, a higher CTR lowers your cost per click at the same CPM, because the same spend buys more clicks. The relationship CPC = CPM / (1,000 x CTR) is useful when you are comparing a CPM buy with a CPC buy.
| CPM | CTR 0.5% | CTR 1% | CTR 2% |
|---|---|---|---|
| $5 | $1.00 | $0.50 | $0.25 |
| $10 | $2.00 | $1.00 | $0.50 |
| $20 | $4.00 | $2.00 | $1.00 |
Publishers use the same idea in reverse. Effective CPM, or eCPM, expresses what an ad slot earns per thousand impressions even when it is sold by click, using (CPC x CTR) x 1,000. See the percentage calculator if you need to turn a CTR into a count of clicks. Enter clicks above and the tool works as a CPC calculator and a CTR calculator at the same time.
What are CPA and ROAS, and how do I use the ROAS calculator?
CPA is cost per acquisition, ad spend divided by conversions, and ROAS is return on ad spend, revenue divided by ad spend. Spending $500 for 25 conversions is a $20 CPA. If those conversions bring $2,000 in revenue, ROAS is 4.00x. Open "More options" in the calculator to enter conversions and revenue.
CPM measures the price of reach. CPA and ROAS measure what that reach produced. A cheap CPM does not help if few people click or buy, and an expensive CPM can still pay off if the audience converts well. The calculator keeps these optional because most people searching for a CPM calculator only need the first three numbers.
Conversion rate here means conversions divided by clicks. Definitions of a conversion differ by platform and business, so use the same definition you use in your own reports.
Is a high or low CPM good?
A lower CPM is cheaper reach, but neither high nor low is good on its own. The right CPM depends on your audience, placement, format and what each impression is worth to you. Compare CPM together with CTR, CPA and ROAS from your own past campaigns, not against a generic industry figure.
This page does not list industry benchmark CPMs, because published numbers vary widely by platform, country, season and audience, and old figures go stale fast. Your own history is the best benchmark. Run the calculator on your last few campaigns and compare spend, CPM, CTR and CPA side by side. Premium audiences and scarce placements tend to cost more per thousand, and broad audiences usually cost less, but that is a tendency you should confirm in your own data.
Frequently asked questions
What does CPM stand for?
CPM stands for cost per mille, where "mille" is Latin for thousand. It is the price paid for 1,000 ad impressions. Google Ads also offers CPM bidding, where you pay per thousand impressions on the Display Network instead of per click.
What is the CPM formula?
CPM = (total ad cost / impressions) x 1,000. For example, $750 spent on 150,000 impressions is $750 / 150,000 = $0.005 per impression, so the CPM is $5.00. The calculator can also solve for spend or impressions.
How do I calculate CPM from CPC and CTR?
Multiply CPC by CTR (as a decimal) and by 1,000. A $0.50 CPC with a 1% CTR gives 0.50 x 0.01 x 1,000 = $5.00 CPM. This figure is often called effective CPM, or eCPM.
What is eCPM?
Effective CPM is the revenue or cost per 1,000 impressions when an ad is sold on another basis, such as per click. It lets you compare CPC, CPA and CPM deals on one scale, using (CPC x CTR) x 1,000.
What is vCPM?
Viewable CPM, or vCPM, means you pay per 1,000 viewable impressions, only counting ads that had a chance to be seen. Google Ads describes vCPM as the highest amount you set for each 1,000 viewable impressions on the Display Network.
Why does my ad platform report a different CPM?
Platforms count impressions and cost in their own ways and may round, exclude invalid traffic or include fees. Use this calculator for a clean check of the arithmetic, and trust the platform invoice for billing.
How do I calculate CTR from clicks and impressions?
Divide clicks by impressions and multiply by 100 for a percentage. Google Ads Help gives the formula as clicks divided by impressions. 1,000 clicks on 100,000 impressions is a 1.00% CTR.
Is CPM better than CPC?
Neither is always better. CPM suits awareness goals where reach matters, and CPC suits goals where you want visits. Compare them with CPC = CPM / (1,000 x CTR) using your own CTR.