Free tool
CPM calculator: cost per thousand impressions
Convertica's free CPM calculator works out CPM, total cost or impressions from the other two. Two more calculators give eCPM and RPM for publishers and creators, and turn a CPM into cost per click and cost per acquisition, so placements can be compared on what a sale costs. Any currency.
Short answer
A CPM calculator divides the total cost of an ad campaign by its impressions and multiplies by 1,000. The result is CPM, the cost per thousand impressions, also called cost per mille. The same formula runs backwards to give total cost or impressions, and publishers apply it to earnings to get eCPM and RPM.
- CPM = total cost / impressions × 1,000. Any two of cost, impressions and CPM give the third.
- eCPM and RPM put earnings in place of cost: eCPM per 1,000 ad impressions, RPM per 1,000 page views or video views.
- CPM is the price of being shown, not a result. Divide it by click-through rate and conversion rate to get cost per acquisition.
- There is no universal good CPM. A good one works out to a cost per acquisition below your break-even CPA.
- Compare CPMs only when the impressions are counted the same way: served, viewable or per playback.
CPM calculator
Free to use, no sign-up. Any currency. Choose what to calculate and enter the other two values. The result updates as you type.
CPM (cost per 1,000 impressions)
4.00
1,200 cost ÷ 300,000 impressions × 1,000 = 4.00 per 1,000 impressions.
That is 0.004 per single impression.
Formula
CPM = total cost / impressions * 1,000
total cost = CPM * impressions / 1,000
impressions = total cost / CPM * 1,000eCPM and RPM calculator
For publishers, app developers and creators: what your ad space earned per thousand. Enter either count, or both.
eCPM (earnings per 1,000 ad impressions)
2.50
eCPM: 150 earnings ÷ 60,000 ad impressions × 1,000 = 2.50 per 1,000 ad impressions.
RPM: 150 earnings ÷ 25,000 views × 1,000 = 6.00 per 1,000 views.
That is 2.4 ad impressions per view, which is why RPM is 2.4 times eCPM.
Both are averages of what was earned. They do not say what the next thousand will pay.
Formula
eCPM = earnings / ad impressions * 1,000
RPM = earnings / views * 1,000
= eCPM * ad impressions per viewCPM to CPC and CPA calculator
What a click and a conversion cost at a given CPM, so placements can be compared on results and not on the price of being shown.
Effective cost per acquisition (eCPA)
100.00
Effective CPC: 4.00 CPM ÷ (1,000 × 0.2%) = 2.00 per click. 1,000 impressions bring 2 clicks.
Effective CPA: 2.00 per click ÷ 2% conversion rate = 100.00 per conversion.
One conversion takes about 25,000 impressions.
That is 20.00 above your break-even CPA of 80.00, so each conversion loses about 20.00 on its first sale.
Break-even CPM at these rates: 80.00 × 0.2% × 2% × 1,000 = 3.20. Above that, this placement loses money on the first sale.
Formula
effective CPC = CPM / (1,000 * click-through rate)
effective CPA = effective CPC / conversion rate
break-even CPM = break-even CPA * click-through rate * conversion rate * 1,000What is the CPM formula?
The CPM formula is total cost divided by impressions, multiplied by 1,000. CPM stands for cost per mille (mille is Latin for thousand), so it is the price of 1,000 ad impressions. With 1,200 spent on 300,000 impressions, CPM is 1,200 / 300,000 × 1,000 = 4.00, or 0.004 per impression.
CPM = total cost / impressions * 1,000
total cost = CPM * impressions / 1,000
impressions = total cost / CPM * 1,000The formula has three values, so any two give the third. The first form checks what a campaign cost per thousand, the second prices a media plan, and the third shows how far a budget goes. An impression is counted each time an ad is shown, whether or not anyone clicks: Google Ads counts one each time your ad appears on a search results page or another site on its network.
How to use the CPM calculator
- Choose what to calculate. CPM, total cost or impressions. The calculator hides that field and works it out from the other two.
- Enter the two values you know. Take both from the same campaign and the same dates. Decimals are fine, and 300k or 1.2m are read as thousands and millions.
- Read the result and the arithmetic under it. For CPM, the panel also shows the cost of a single impression.
- Selling ad space? Use the second calculator. Earnings and ad impressions give eCPM; earnings and page views or video views give RPM.
- Turn the CPM into a result. Put it into the third calculator with your click-through rate and conversion rate to see what a click and a conversion cost.
How to calculate CPM: worked examples
To calculate CPM, take the total cost of a campaign, divide it by the impressions it delivered over the same dates, and multiply by 1,000. To plan, turn the formula around: multiply a quoted CPM by the impressions you want, or divide a budget by the CPM. The numbers below are made up to show the arithmetic; they are not benchmarks.
CPM from cost and impressions
- Cost: 1,200. Impressions: 300,000.
- Cost per impression = 1,200 / 300,000 = 0.004.
- CPM = 0.004 × 1,000 = 4.00.
Total cost from CPM and impressions
A site quotes a CPM of 4.00 and you want 500,000 impressions. Cost = 4.00 × 500,000 / 1,000 = 2,000.00.
Impressions from a budget and a CPM
With a budget of 3,000 at the same CPM: 3,000 / 4.00 × 1,000 = 750,000 impressions. When the answer is not a whole number, round down: 1,000 at a CPM of 7.50 is 133,333.33, so 133,333 impressions.
CPM vs eCPM vs RPM vs vCPM
CPM, eCPM, RPM and vCPM all express money per thousand, but they count different things for different people. CPM and vCPM are prices an advertiser pays, per thousand impressions served or per thousand viewable impressions. eCPM and RPM are what a publisher, app or creator earned, per thousand ad impressions or per thousand views.
| Metric | What it measures | Formula |
|---|---|---|
| CPM (cost per mille) | What an advertiser pays for 1,000 impressions | Cost / impressions × 1,000 |
| vCPM (viewable CPM) | What an advertiser pays for 1,000 impressions measured as viewable | Cost / viewable impressions × 1,000 |
| tCPM (target CPM) | The average CPM an advertiser asks the platform to aim for | A bid setting, not a result |
| eCPM (effective CPM) | What a publisher or app earned per 1,000 ad impressions | Earnings / ad impressions × 1,000 |
| RPM (revenue per mille) | What a publisher or creator earned per 1,000 page views or video views | Earnings / views × 1,000 |
| Playback-based CPM | What advertisers paid per 1,000 video playbacks that showed an ad, as reported to YouTube creators | Advertiser cost / playbacks with an ad × 1,000 |
How the platforms themselves define each one, in their help centers:
- CPM. Google Ads Help calls it a way to bid where you pay per one thousand views (impressions) on the Google Display Network.
- vCPM. In Google Ads you bid on 1,000 viewable impressions and pay for those measured as viewable: half the ad on screen for one second or longer, or two seconds or longer for video.
- tCPM. Google Ads Help describes it as the average you are willing to pay per thousand impressions, for video campaigns. Google Ads tries to keep the campaign's average CPM at or below it.
- eCPM. Google AdMob Help calls it an estimate of the revenue you receive for every thousand ad impressions.
- RPM. AdSense Help calculates page RPM as estimated earnings divided by page views, times 1,000. YouTube Help defines RPM as revenue per 1,000 video views, after YouTube's revenue share.
- Playback-based CPM. YouTube Help defines it as the cost an advertiser pays for 1,000 video playbacks where an ad is displayed.
eCPM and RPM: the publisher's side
eCPM is called effective because it does not matter how the ads were sold. Earnings from ads bought per click, per impression or per action are all divided by the ad impressions that produced them. AdSense uses RPM for the same idea: its help center divides estimated earnings by page views, impressions or queries, depending on the report, and multiplies by 1,000.
The two are linked by how many ads each view shows. In the calculator's example, 150 earned from 60,000 ad impressions is an eCPM of 2.50, and the same earnings over 25,000 page views is an RPM of 6.00. Each page view showed 2.4 ads on average, so RPM is 2.4 times eCPM.
RPM = eCPM * ad impressions per viewBoth are averages of money already earned. AdSense's own help page says RPM does not represent how much you have actually earned, and neither figure says what the next thousand views will pay.
CPM and RPM on YouTube
In YouTube Analytics, CPM is the advertiser's cost per 1,000 ad impressions before YouTube's revenue share, and RPM is the creator's total revenue per 1,000 video views after it. YouTube's help center gives two reasons RPM is the lower number: it is calculated after the revenue share, and it counts every view, including views that showed no ad.
An illustration with made-up numbers: a video has 10,000 views and 8,000 ad impressions. Advertisers paid 40.00 for those impressions, so CPM is 5.00. If the creator's revenue from the video is 24.00, RPM is 24.00 / 10,000 × 1,000 = 2.40. To estimate earnings from an RPM, multiply it by views and divide by 1,000; the first calculator does that sum if you read CPM as RPM and impressions as views. Treat the answer as an estimate: YouTube says CPM moves with the time of year and with where viewers are.
vCPM: paying only for impressions that could be seen
An ad can be served far down a page and never come into view. Viewable CPM prices only the impressions measured as viewable. For the same spend, vCPM is never lower than CPM, because fewer impressions are counted, so do not set a vCPM quote beside a CPM quote as if they were the same unit. In Google Ads the choice is already made on the Display Network: its help center says Max. CPM is no longer available as a bid strategy, and you bid on viewable impressions.
How to convert CPM to CPC and CPA
To convert CPM to CPC, divide the CPM by 1,000 times the click-through rate. To go on to CPA, divide that cost per click by the conversion rate. A CPM of 4.00 at a 0.2% click-through rate is 2.00 per click; at a 2% conversion rate, that is 100.00 per conversion.
effective CPC = CPM / (1,000 * click-through rate)
effective CPA = effective CPC / conversion rate
= CPM / (1,000 * click-through rate * conversion rate)This is why a cheap CPM can be an expensive way to buy sales. Take two placements bought with the same 1,200 budget. Placement B's CPM is 3 times placement A's, but its ad is clicked 5 times as often. Both send visitors to the same page, which converts 2% of clicks.
| Measure | Placement A | Placement B |
|---|---|---|
| CPM | 4.00 | 12.00 |
| Impressions bought | 300,000 | 100,000 |
| Click-through rate | 0.2% | 1% |
| Clicks | 600 | 1,000 |
| Effective CPC | 2.00 | 1.20 |
| Conversion rate | 2% | 2% |
| Conversions | 12 | 20 |
| Effective CPA | 100.00 | 60.00 |
| Against break-even CPA (80.00) | 20.00 above | 20.00 below |
| Break-even CPM | 3.20 | 16.00 |
Judged on CPM, A wins easily. Judged on what a sale costs, B wins: 20 sales at 60.00 each against 12 at 100.00. With an average order value of 200 and a 40% gross margin, break-even CPA is 200 × 0.40 = 80.00 (the CPA formula page explains that line). A loses 20.00 on every first sale and B keeps 20.00.
Break-even CPM: the most a placement is worth
Turn the formula around and you get the highest CPM a placement can carry before it loses money: break-even CPA × click-through rate × conversion rate × 1,000. For placement A that is 80.00 × 0.2% × 2% × 1,000 = 3.20, below the 4.00 it costs. For placement B it is 16.00, above the 12.00 it costs.
break-even CPM = break-even CPA * click-through rate * conversion rate * 1,000If you do not know the two rates yet, the CTR calculator and the conversion rate calculator work them out from clicks, impressions and conversions.
What is a good CPM?
A good CPM is one that, at your click-through rate and conversion rate, works out to a cost per acquisition below your break-even CPA. Put the other way, it is any CPM under your break-even CPM. There is no universal good figure, because what an impression is worth depends on your own rates and margin.
In the example above, the same 4.00 CPM that loses money for placement A would be a bargain at placement B's click-through rate. That is why this page publishes no average CPM by platform, country or industry. An average across advertisers with different audiences, formats, prices and margins cannot say what an impression is worth to you, and a CPM below the average can still lose money. Your break-even CPM can, and it uses numbers you already have.
How conversion rate changes the CPM you can afford
Break-even CPM rises in step with conversion rate. At placement A's 0.2% click-through rate and a break-even CPA of 80.00, each step up in conversion rate raises what a thousand impressions are worth:
| Conversion rate | Effective CPA at a 4.00 CPM | Against break-even (80.00) | Break-even CPM |
|---|---|---|---|
| 1% | 200.00 | 120.00 above | 1.60 |
| 2% (current) | 100.00 | 20.00 above | 3.20 |
| 2.5% | 80.00 | At break-even | 4.00 |
| 3% | 66.67 | 13.33 below | 4.80 |
| 4% | 50.00 | 30.00 below | 6.40 |
At 2%, a 4.00 CPM loses money. At 2.5% it breaks even, and at 4% the same audience is worth up to 6.40 per thousand. A page that converts better does two things for whoever buys the media: placements that lost money can start to pay, and you can afford a higher CPM than before for the same impressions. The ad platform cannot change your conversion rate; the page after the click can.
Convertica's free CRO audit checks the page your ads send people to: the first screen, calls to action, forms, trust, mobile, speed and AI agent readiness. The landing page analyzer is a quicker check of one page.
When there is no conversion to count
For reach and awareness campaigns with no click or sale to measure, compare placements on cost per thousand viewable impressions for the same audience, and on how often the same people see the ad. Then judge the campaign by what it was meant to move, such as branded searches or direct visits, measured in your own data.
CPM vs CPC vs CPA: which way to buy?
CPM, CPC and CPA are three ways to pay for the same advertising: per thousand impressions, per click or per conversion. The further down the funnel you pay, the more of the risk the seller carries, and the more each unit costs. Whichever one is on the invoice, compare the options on effective CPA.
| Model | You pay for | Who carries the risk | It makes sense when | Watch for |
|---|---|---|---|---|
| CPM (cost per thousand impressions) | Every 1,000 impressions, clicked or not | The advertiser: a low click-through rate or conversion rate is your cost | The goal is reach or awareness, the format has little to click, or you already know the placement's click-through rate | Impressions nobody could see, and the same people seeing the ad too often |
| CPC (cost per click) | Each click | Shared: the seller carries click-through rate, you carry conversion rate | The goal is traffic that converts on your own page | Clicks that do not convert: the landing page decides whether a click was worth its price |
| CPA (cost per acquisition or action) | Each conversion | The seller: you pay for results only | Conversions are tracked reliably and both sides agree what one is, as in affiliate programs | What counts as a conversion, and sales that would have happened anyway |
Paying per impression makes the most sense when you can work out the break-even CPM before you buy, from a click-through rate and a conversion rate in your own past campaigns, and turn down anything priced above it. It makes the least sense when you have no history for the placement and the seller gives no viewability figure: then you carry all of the risk without seeing it. Start with a small test, measure both rates, and work out the effective CPA before committing a budget.
How to calculate CPM in Excel or Google Sheets
To calculate CPM in Excel or Google Sheets, put cost in one column and impressions in the next, divide cost by impressions and multiply by 1,000. With cost in B2 and impressions in C2, the formula is =B2/C2*1000. The formulas below work the same way in both programs.
| To get | Formula | Example |
|---|---|---|
| CPM | =B2/C2*1000 | 1,200 and 300,000 give 4.00 |
| CPM, blank when there are no impressions | =IF(C2=0,"",B2/C2*1000) | An empty cell, not an error or a 0 |
| Total cost | =D2*C2/1000 | 4.00 and 500,000 give 2,000.00 |
| Impressions, rounded down | =ROUNDDOWN(B2/D2*1000,0) | 1,000 and 7.50 give 133,333 |
| Effective CPC | =D2/(1000*E2) | 4.00 and 0.2% give 2.00 |
| Effective CPA | =D2/(1000*E2*F2) | 4.00, 0.2% and 2% give 100.00 |
| One CPM for several rows | =SUM(B2:B10)/SUM(C2:C10)*1000 | Total cost over total impressions |
Do not average CPMs
To get one CPM for several placements, divide total cost by total impressions. Averaging the CPM column treats a small placement and a large one as equals. Placements A and B together cost 2,400 for 400,000 impressions, a blended CPM of 6.00. The average of 4.00 and 12.00 is 8.00, a price nobody paid.
Common CPM mistakes
- Comparing different kinds of impression. Served, downloaded and viewable impressions are different counts. AdSense, for example, counts an impression once the ad has begun to download, and a viewable impression needs half the ad on screen. Ask how impressions are counted before you compare two CPMs.
- Judging a placement on CPM alone. A low CPM with a low click-through rate can cost more per sale than a high one. Convert both to CPA.
- Reading tiny numbers. CPM scales whatever you have up to a thousand. 3 spent on 40 impressions is a CPM of 75.00; one more impression makes it 73.17. With no impressions at all, CPM is not defined: leave the row blank, since it is not a CPM of 0.
- Mismatched dates or currencies. Cost from one period divided by impressions from another describes neither.
- Leaving out the costs around the media. Agency fees, ad serving and creative are not in a platform's CPM. Say whether yours is media only or fully loaded.
- Mixing up CPM and RPM. One is what advertisers paid; the other is what the publisher or creator received.
Related calculators and guides
CPM is the first number in a chain that ends at what a customer costs. These tools cover the rest of it.
To raise the two rates that decide what a CPM is worth, see the guides on how to increase click-through rate and on landing page optimization. See all free tools and how they fit together.
CPM calculator FAQ
What is the CPM formula?
The CPM formula is total cost divided by impressions, multiplied by 1,000: CPM = cost / impressions × 1,000. For example, 1,200 spent on 300,000 impressions is a CPM of 4.00. The reverse forms are cost = CPM × impressions / 1,000 and impressions = cost / CPM × 1,000.
How do I use the CPM calculator?
Choose what to calculate (CPM, total cost or impressions), then enter the other two values. The CPM calculator shows the result with the arithmetic behind it and updates as you type. It works in any currency, accepts decimals, and reads 300k or 1.2m as thousands and millions.
What does CPM stand for?
CPM stands for cost per mille, where mille is Latin for thousand. It is the cost of 1,000 ad impressions, also written as cost per thousand impressions. An impression is counted each time an ad is shown, whether or not anyone clicks.
What does a CPM of 15 mean?
A CPM of 15 means 1,000 impressions cost 15 in your currency, which is 0.015 per impression. At that rate, 1,000,000 impressions cost 15,000. The figure says what it costs to be shown, not how many people clicked or bought.
What is the difference between CPM and eCPM?
CPM is a price: what an advertiser pays for 1,000 impressions. eCPM, effective cost per thousand impressions, is a result: what a publisher or app earned per 1,000 ad impressions, whatever the ads were sold on. Google AdMob calculates eCPM as total earnings / impressions × 1,000.
What is the difference between CPM and RPM?
CPM is what advertisers pay per 1,000 ad impressions; RPM is what a publisher or creator earns per 1,000 page views or video views. On YouTube, RPM is lower than CPM because it is calculated after YouTube's revenue share and counts all views, including those that showed no ad.
What is vCPM?
vCPM is viewable CPM: the cost per 1,000 viewable impressions. In Google Ads, a display ad counts as viewable when 50% of it is on screen for one second or longer, and a video ad when it plays for two seconds or longer. For the same spend, vCPM is never lower than CPM, because fewer impressions are counted.
How do I convert CPM to CPC?
Divide CPM by 1,000 times the click-through rate: CPC = CPM / (1,000 × CTR). A CPM of 4.00 at a 0.2% click-through rate is 4.00 / 2 = 2.00 per click. Divide that by the conversion rate to get cost per acquisition: 2.00 / 2% = 100.00.
What is a good CPM?
A good CPM is one that works out to a cost per acquisition below your break-even CPA once click-through rate and conversion rate are applied. There is no universal good figure. In the example on this page, a 12.00 CPM beats a 4.00 CPM because it produces sales at 60.00 each instead of 100.00.
Is it better to pay by CPM or by CPC?
Neither is better in itself: compare them on cost per acquisition. Paying by CPM suits reach and awareness, and placements whose click-through rate you already know. Paying by CPC moves the risk of a low click-through rate to the seller. Convert both to cost per acquisition and choose the lower one.
How do I calculate CPM in Excel or Google Sheets?
Put cost in B2 and impressions in C2, then enter =B2/C2*1000. To avoid an error on rows with no impressions, use =IF(C2=0,"",B2/C2*1000). For the CPM of several rows together, divide total cost by total impressions with =SUM(B2:B10)/SUM(C2:C10)*1000, not the average of the CPM column.