CPM Calculator
Find cost per 1,000 impressions, estimate campaign spend or impressions, and compare advertising costs. Enter amounts in the same currency.
- Campaign spend
- 500
- Impressions
- 100,000
- CPM
- 5
Amounts use your chosen currency. Estimated impressions and clicks may be fractional; actual counts are whole numbers.
Show working
CPM = spend / impressions x 1,000 500 / 100,000 x 1,000 = 5
What is CPM?
CPM means cost per mille: the cost per 1,000 impressions. Advertisers use it to compare the price of delivering ads, even when campaigns have different budgets or impression counts. It is a cost rate, not a percentage.
CPM = campaign spend / impressions x 1,000
Spending 500 on 100,000 impressions gives CPM = 5. The result uses the same currency as your spending input. You can use dollars, pounds or another currency, provided you do not mix currencies within a comparison.
Calculate campaign cost or impressions
| Find | Formula | Example |
|---|---|---|
| CPM | Spend / impressions x 1,000 | 500 / 100,000 x 1,000 = 5 |
| Spend | CPM x impressions / 1,000 | 8 x 250,000 / 1,000 = 2,000 |
| Impressions | Spend / CPM x 1,000 | 750 / 6 x 1,000 = 125,000 |
An impression forecast assumes the entered CPM applies throughout the campaign. Auction pricing, placement mix and delivery can change, so actual impressions may differ. Fractional impression estimates are mathematical outputs; real delivered impressions are counted in whole numbers.
Compare the cost of two campaigns
Campaign A spends 500 for 100,000 impressions, giving CPM 5. Campaign B spends 600 for 150,000 impressions, giving CPM 4. B costs more in total but is 20% cheaper per 1,000 impressions.
The comparison uses A as the baseline: (CPM B – CPM A) / CPM A x 100. This is a relative change, not the symmetric calculation on the percentage difference calculator. A lower CPM alone does not establish better campaign performance; audience quality, viewability and outcomes may differ.
CPM versus CPC, CTR and RPM
CPM measures impression cost. To plan the traffic needed for a conversion target, use the conversion rate calculator with a clearly defined visitor, session or click basis.
CPC is cost per click. CTR is clicks divided by impressions, expressed as a percentage. Adding a CTR estimate lets this calculator estimate clicks and implied CPC from the same impressions and spend.
Estimated clicks = impressions x CTR / 100
Implied CPC = spend / estimated clicks
With 100,000 impressions, spend of 500 and CTR of 2%, the estimate is 2,000 clicks and CPC 0.25. Use the CTR calculator to calculate the click rate or solve a click target. Zero estimated clicks makes CPC undefined, even when campaign spend is zero.
Publisher RPM measures revenue per 1,000 units, such as pageviews, sessions or ad impressions. Those units matter. Advertiser CPM is not the same as publisher page RPM or session RPM, and this calculator does not predict ad-network earnings.
Common questions
Should I include tax or agency fees?
Use the cost basis you want to compare and apply it consistently. Platform-reported media CPM normally uses the platform’s spend figure. An all-in campaign cost comparison may include other charges, but label that distinction.
Is a low CPM always good?
No. A cheaper impression can reach a different audience or placement. Compare cost alongside the campaign objective and measured results; this tool makes no quality judgment from price alone.
Why can I not solve impressions using zero CPM?
The formula divides spend by CPM. At zero CPM, that equation does not determine a finite unique impression count.
Related calculators
Back to the Percent Calculator.