CPM Calculator

Work out cost, impressions or CPM, estimate publisher revenue and eCPM, and compare CPM, CPC and CPA offers on one basis.

CPM calculator

What do you want to work out?

Cost per 1,000 impressions

Add clicks, conversions and viewability

How far the CPM might move

Leave the optional fields blank to skip them.

Impressions you can buy

800,000

$5,000 ÷ $6.25 × 1,000

Also worked out

Cost per impressionCPM ÷ 1,000
$0.00625

If your CPM comes in higher or lower

CaseCPMImpressions
Low$4.691,066,667
Expected$6.25800,000
High$7.81640,000
Your CPMCPM $6.25Impressions 800,000

Open dots mark the low and high scenarios.

Impressions $5,000 buys at different CPMs, falling as CPM rises. At $6.25 it buys 800,000.
CPMImpressions
$2.502,000,000
$3.781,323,944
$5.05989,474
$6.33789,916
$7.61657,343
$8.88562,874
$10.16492,147
$11.44437,209

CPM is the price of reaching a thousand people: cost per mille, "mille" being Latin for a thousand. This free online CPM calculator works it in whichever direction you need: give it a budget and a CPM to get the impressions, a cost and the impressions to get the CPM, or turn a publisher's impressions into revenue and an eCPM. When vendors quote by CPM, by click or by conversion, it puts the offers on one basis so the cheaper one is obvious.

Reviewed by Bunny Corner TeamHow we source our numbers

How it works

  1. Pick what you want to work out. As an ad buyer you can solve for impressions, cost or CPM, and the calculator asks only for the two figures it needs. As a publisher you can estimate revenue or work out your eCPM. To choose between quotes, use Compare offers.
  2. Enter your numbers. Everything works from the two or three fields shown. Add click-through rate, conversion rate or viewability under the optional section if you want click, conversion and viewable-CPM figures too, and leave them blank to skip them.
  3. Read the answer and its working. The headline figure sits above the arithmetic that produced it, so you can check it by hand, and the chart shows how the answer moves as the CPM changes. Copy a summary or a shareable link if you need to send it on.

What a $10 CPM costs per click, at different click-through rates

Click-through rateClicks per 1,000 impressionsCost per click
0.1%1$10.00
0.25%2.5$4.00
0.5%5$2.00
1%10$1.00
2%20$0.50
5%50$0.20

The CPM formula

CPM is the cost of 1,000 impressions: the cost divided by the impressions, multiplied by 1,000. You will also see it called the cost per mille, cost per thousand or price per thousand impressions formula, and they all mean this one calculation.

CPM = cost ÷ impressions × 1,000

Google Ads describes CPM as a way to bid where you pay per one thousand impressions, and the formula restates that price. Divide what you spent by the impressions to find the cost of one impression, then multiply by 1,000. Spend $5,000 for 800,000 impressions and the CPM is $6.25.

It rearranges into the other two forms this calculator solves: cost equals impressions multiplied by CPM, divided by 1,000, and impressions equal cost divided by CPM, multiplied by 1,000.

How to calculate CPM, step by step

To work out, figure out or determine a CPM, divide the total cost by the impressions, then multiply by 1,000.

  1. Take the total cost of the campaign and the impressions it delivered, both for the same period.
  2. Divide the cost by the impressions to get the price of one impression: $5,000 ÷ 800,000 = $0.00625.
  3. Multiply by 1,000 to express it per thousand: $0.00625 × 1,000 = $6.25.

Two mistakes cause most wrong answers. The first is mixing units, such as a cost in dollars against impressions reported in thousands, which makes the answer off by a factor of 1,000. The second is using clicks or views where impressions belong: CPM is priced per impression served, not per click and not per video view.

Cost per impression and cost per thousand

Cost per impression is the price of one impression: the total cost divided by the impressions delivered.

Cost per impression = cost ÷ impressions; CPM = cost per impression × 1,000

A $2,400 campaign that delivered 600,000 impressions cost $0.004 per impression, a fraction of a cent, which is why prices are quoted per thousand. Multiply by 1,000 and it is a $4 CPM. CPM is also called cost per 1,000 impressions, cost per thousand or cost per mille.

If a vendor quotes a cost per impression, multiply it by 1,000 to get a CPM you can compare. If they quote a CPM, divide it by 1,000 to get the price of one impression. The ad buyer mode shows the cost per impression next to the CPM.

Impressions formula: how to calculate ad impressions

To find impressions from a budget, divide the budget by the CPM and multiply by 1,000.

Impressions = budget ÷ CPM × 1,000

Planning usually runs this way: you have a budget and a quoted CPM and need the reach. $5,000 at a $6.25 CPM buys 800,000 impressions.

The relationship is inverse. Halve the CPM and the same budget buys twice the impressions; double it and you get half. That is why the chart in the calculator is a curve rather than a straight line, and why the low and high scenarios matter: a CPM 25% under your estimate buys a third more impressions, while one 25% over costs you a fifth of them, because the curve is steeper on the cheap side.

If you have results rather than a budget, work impressions back from clicks: divide the clicks by the click-through rate written as a decimal. Google Ads defines click-through rate as clicks divided by impressions, so 400 clicks at a 0.5% click-through rate means 400 ÷ 0.005, or 80,000 impressions.

eCPM formula and RPM: the publisher's view

eCPM, effective CPM, is the revenue a publisher earns per thousand impressions served: revenue divided by impressions, multiplied by 1,000.

eCPM = revenue ÷ impressions × 1,000

It is the same division as CPM, applied to earnings instead of spend. A publisher does not set a CPM so much as discover one, and eCPM lets them compare ad sources that pay in different ways on one scale.

Google AdSense reports the same idea as RPM. It defines impression RPM as estimated earnings divided by impressions, multiplied by 1,000, and page RPM as estimated earnings divided by page views, multiplied by 1,000. The distinction matters: if every slot on a page with three ad slots is filled, its page RPM is three times its impression RPM.

Publisher mode also lets you apply a fill rate, the share of ad slots that actually got an ad, and a revenue share, what you keep after a network takes its cut. It reports the effective eCPM after both.

CPM, CPC and CPA: comparing offers quoted differently

To compare a CPM with a CPC or a CPA, put them all on one basis using your click-through rate and conversion rate.

Cost per click = CPM ÷ (1,000 × click-through rate)

A CPM of $8 and a CPC of $0.90 cannot be compared until they share a unit. Google Ads defines click-through rate as clicks divided by impressions and conversion rate as conversions divided by ad interactions. At a 0.8% click-through rate, an $8 CPM works out to $8 ÷ (1,000 × 0.008), which is $1.00 a click. A CPA converts to a cost per click by multiplying it by the conversion rate.

Compare offers does these conversions for you and shows every quote per 1,000 impressions, per click and per conversion. Treat the winner as conditional on the rates you entered: change the click-through rate and a CPM offer can move from the most expensive quote to the cheapest.

Viewable CPM (vCPM)

Viewable CPM is the cost per thousand impressions that were actually viewable: the cost divided by the viewable impressions, multiplied by 1,000.

vCPM = cost ÷ viewable impressions × 1,000

Not every impression that is served is seen. Under the Media Rating Council standard that Google follows, a display ad counts as viewable when at least 50% of its area is visible on screen for at least one second (30% for very large ads), and a video ad when at least 50% is visible while playing for at least two seconds.

Viewable CPM bidding, in Google's words, means you bid on 1,000 viewable impressions and pay for impressions that are measured as viewable. The vCPM of a standard CPM buy is never lower than the plain CPM, and the gap is the price of the impressions nobody saw. Enter a viewability percentage in the ad buyer options to see it.

What moves a CPM up or down

A CPM reflects the platform, the audience being reached, the ad format, where the ad appears and the time of year.

This page deliberately quotes no average CPM, because there is no honest single figure. On auction-based platforms a CPM also reflects how many advertisers want the same audience at the same moment, which is why CPMs shift with the season and with how narrowly a campaign is targeted.

A narrow, valuable audience often costs more per thousand than a broad one, and a format that holds attention often costs more than one that scrolls past. So the practical use of a calculator is not to look up a "normal" CPM but to turn the quotes and results you actually have into a comparable figure.

Frequently asked questions

What does CPM mean?

CPM stands for cost per mille, mille being the Latin word for a thousand, so it is the cost per thousand impressions. The full name is cost per mille, also called cost per thousand or cost per 1,000 impressions. The M comes from mille, not from "million": a CPM prices every thousand times an ad is shown.

How is CPM calculated?

Divide the total cost by the number of impressions, then multiply by 1,000. The result is the CPM rate. A $5,000 campaign that delivered 800,000 impressions has a CPM of $5,000 ÷ 800,000 × 1,000, which is $6.25. The calculator above runs that in the ad buyer mode when you choose to solve for CPM, and shows the working under the answer so you can check it by hand.

What is the CPM formula?

CPM = (cost ÷ impressions) × 1,000. It rearranges into cost = impressions × CPM ÷ 1,000 and impressions = cost ÷ CPM × 1,000, and the calculator solves all three. Google Ads describes CPM as a way to bid where you pay per one thousand impressions, which is the same idea stated as a price rather than a formula.

What does a $10 CPM mean?

A $10 CPM means you pay $10 for every 1,000 impressions, which is $0.01 per impression. Reaching 100,000 impressions costs $1,000 and a million impressions costs $10,000. A CPM of 7 reads the same way: $7 per thousand impressions, or $0.007 each. A CPM says nothing about clicks, so what it costs per click depends on the click-through rate: at 1% it works out to $1.00 a click.

How much is 1 CPM?

One CPM is the price of 1,000 impressions, so how much it costs depends on the rate. At a CPM of $1, $1 buys 1,000 impressions, or $0.001 per impression. At a $6.25 CPM, one CPM costs $6.25 and 800 of them, which is 800,000 impressions, cost $5,000.

Is CPM per 1,000 views?

No, CPM is per 1,000 impressions: each time an ad is shown. A view is different. A viewable impression counts only ads that were actually on screen (see vCPM below), and a video view is its own metric, which video ads can be bought on as cost per view (CPV).

How do you calculate impressions?

Divide the budget by the CPM and multiply by 1,000: $5,000 at a $6.25 CPM buys 800,000 impressions. From results, divide clicks by the click-through rate written as a decimal: 400 clicks at 0.5% is 80,000 impressions. In the ad buyer mode, choose Impressions and enter the budget and CPM.

How do I calculate CPM in Excel or Google Sheets?

Put the cost in one cell and the impressions in another, then divide and multiply by 1,000. If the cost is in B2 and the impressions are in C2, the formula is =B2/C2*1000. To get impressions from a budget in B2 and a CPM in D2, use =B2/D2*1000, and for the cost of a known number of impressions use =C2*D2/1000.

What is a good CPM, and what is a bad one?

There is no single good CPM, and this calculator deliberately quotes none: it depends on the platform, audience, format, placement and season. A bad CPM is one that looks cheap but delivers poor value, such as low-priced impressions few people see or click. Judge it by what it works out to per click or per conversion at your own rates, using Compare offers.

Is a higher CPM better?

It depends which side you are on. For an advertiser a lower CPM means more impressions for the same budget, though it is no bargain if few are seen or clicked. For a publisher a higher CPM means more revenue from the same traffic. Compare on cost per click or per conversion, not on CPM alone.

How can I lower my CPM?

A CPM is set by what you buy: how narrowly you target, the ad format, where the ad runs and when. Broader audiences and less contested placements and periods usually cost less per thousand. A lower CPM only helps if the cost per click or per conversion does not rise with it, so check that in Compare offers first.

What is the difference between CPM, CPC and CPA?

They are three ways to pay for the same ad: CPM per thousand impressions, CPC per click and CPA per acquisition, or conversion. CPM charges for being shown and CPA for a result, so performance risk moves from the advertiser to the seller from one to the other. Compare offers puts quotes in different terms on one basis using click-through and conversion rates.

How do I convert CPM to CPC?

Divide the CPM by 1,000 times your click-through rate, written as a decimal. A $10 CPM at a 1% click-through rate is $10 ÷ (1,000 × 0.01), which is $1.00 per click. The result depends entirely on the click-through rate you assume, which is why Compare offers asks for it: change it and the cost per click changes with it.

How do I convert CPC to CPM?

Multiply the CPC by 1,000 times your click-through rate, written as a decimal. A $1.00 CPC at a 1% click-through rate is $1.00 × 1,000 × 0.01, which is a $10 CPM. Enter both offers in Compare offers and it shows each one per 1,000 impressions as well as per click and per conversion.

What is eCPM, and how is it different from CPM?

CPM is what an advertiser pays per thousand impressions; eCPM, effective CPM, is what a publisher earns per thousand impressions served. Both are a total divided by impressions, multiplied by 1,000. For a publisher, eCPM is the useful figure because it puts income from ad sources that pay differently, by impression, by click or by conversion, on one scale. Publisher mode calculates it from your revenue and impressions.

What is the difference between CPM and RPM?

They are the same calculation with a different denominator in some reports. Google AdSense defines impression RPM as estimated earnings divided by impressions, multiplied by 1,000, which is an eCPM. It defines page RPM as estimated earnings divided by page views, multiplied by 1,000, so a page that shows several ads has a higher page RPM than impression RPM.

What is vCPM?

Viewable CPM is the cost per thousand impressions that were actually viewable: cost ÷ viewable impressions × 1,000. Under the Media Rating Council standard Google follows, a display ad is viewable when at least 50% is on screen for at least one second, and a video ad for at least two seconds. Add a viewability percentage in the ad buyer options and the calculator does the sum.

What do fill rate and revenue share mean in publisher mode?

Fill rate is the share of your ad slots that got an ad: 100 slots at an 80% fill rate serve 80 ads. Revenue share is the portion of the advertiser's payment you keep after the network's cut. Both lower what you earn per impression, and publisher mode reports the effective eCPM after applying them.

Does this calculator store or send my numbers anywhere?

No. The calculation runs in your browser and nothing you enter is sent to a server. The Copy link button builds a link that carries your inputs in the address, and that link only reaches someone if you choose to share it.

Where our numbers come from

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