CPM Calculator
With amount spent 2500 usd, impressions delivered 500000, clicks 4000, conversions 120 and 1 more field, cpm comes to $5.00 — cost per thousand. It is reached in 7 steps, the last of which is (2500 / 500000) * 1000, and each one is printed on the page with its numbers filled in. The formula is the one published by IAB, not an approximation fitted to it.
Cost per thousand impressions, and the two numbers it hides: what a click actually cost and what the campaign returned.
Formula and sources checked · How we check
Amount spent 2500, Impressions delivered 500000, Clicks 4000, Conversions 120
$5.00
Cost per thousand for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Cost per thousand impressions
(2500 / 500000) * 1000$5 usd- Click-through rate
(4000 / 500000) * 1000.8 %- Cost per click
2500 / 4000$0.63 usd- Conversion rate of clicks
(120 / 4000) * 1003 %- Cost per conversion
2500 / 120$20.83 usd- Return on ad spend
9000 / 25003.6 ×- Revenue less spend
9000 - 2500$6,500 usd
Worked example
$2,500 across 500,000 impressions is a $5.00 CPM. The same buy is a 0.8% click rate and a $0.63 cost per click, 120 conversions at $20.83 each, and $3.60 back for every dollar spent. The CPM is the price; the last two figures are whether it was worth paying.
How to work it out yourself
- 1.Divide the spend by the impressions and multiply by a thousand — the M in CPM is the Roman thousand, not million.
- 2.Cost per click is spend over clicks, which is the same money divided a different way.
- 3.Cost per conversion is spend over conversions, and it is the one a finance department recognises.
- 4.Return on ad spend is revenue over spend: below 1 the campaign lost money whatever the CPM said.
CPM at $2,500 spend by impressions delivered
| Impressions delivered | Cost per thousand | Cost per click |
|---|---|---|
| 100000 | $25.00 | $1 |
| 250000 | $10.00 | $1 |
| 500000 | $5.00 | $1 |
| 1000000 | $2.50 | $1 |
| 2000000 | $1.25 | $1 |
A fixed $2,500 buy. More impressions for the same money is a lower CPM, which is not the same as a better campaign.
The formula
- Cost per thousand impressions
(2500 / 500000) * 1000 - Click-through rate
(4000 / 500000) * 100 - Cost per click
2500 / 4000 - Conversion rate of clicks
(120 / 4000) * 100 - Cost per conversion
2500 / 120 - Return on ad spend
9000 / 2500 - Revenue less spend
9000 - 2500
Source: IAB — measurement guidelines for impressions, Media Rating Council — viewable impression standard
Questions people actually ask
- What does CPM stand for?
- Cost per mille — cost per thousand impressions. The M is the Roman numeral for a thousand, not an abbreviation of million, and reading it as million is why a $5 CPM sometimes gets budgeted as if a million impressions cost five dollars.
- How do you calculate CPM?
- Spend divided by impressions, times 1,000. $2,500 over 500,000 impressions is $5.00. To go the other way, a $5 CPM on a $2,500 budget buys 500,000 impressions: budget divided by CPM, times 1,000.
- Is a low CPM good?
- Only if the impressions were worth having. CPM is a price, not a result — the cheapest thousand impressions on the internet reach nobody who will buy. A campaign at a $12 CPM returning $4 per dollar beats one at $2 returning nothing, which is why the cost per conversion sits beside it here.
- What is the difference between CPM, CPC and CPA?
- The same spend divided by three different denominators: impressions, clicks and conversions. CPM is what the platform charges, CPC is what the audience did with it, CPA is what the business got. A campaign can improve on one and worsen on another, so quoting only the first is how a bad buy looks good.
- What is an impression, exactly?
- One serving of the ad, counted when it is fetched or when it is rendered depending on the platform. The IAB and the MRC define a viewable display impression as at least half the pixels in view for at least one second — a stricter test that most platforms report separately, and the gap between served and viewable is often a fifth or more.
Related
- ROI CalculatorReturn on investment as a total percentage and as an annualised rate, so holdings of different lengths compare fairly.
- Margin and Markup CalculatorMargin and markup from cost and price — the two are not the same number, and the page shows both every time.
- Percentage CalculatorWhat X% of a number is, plus the discounted price, the marked-up price and the remainder.
- Salary CalculatorPay converted between every period — hourly, daily, weekly, biweekly, semi-monthly, monthly and annual — with unpaid holidays and days off taken out.
- Tip CalculatorTip and total from a bill, and what each person owes once it is split — including the rounding that makes the split come out even.
- Fuel Cost CalculatorWhat a trip costs in fuel, from its distance, the mileage the vehicle really gets and the pump price — with the cost per mile to compare on.
Put this calculator on your site
Free, no attribution required beyond the link.
<iframe src="https://rulecalculators.com/embed/cpm" width="100%" height="420" style="border:1px solid #e7e4de;border-radius:12px" title="CPM Calculator"></iframe>