Quick answer
CPM = ad spend ÷ impressions × 1,000. $500 for 100,000 impressions is a CPM of $5.00.
Enter spend and impressions. The calculator returns the cost per thousand impressions.
Related tools: Markup Calculator: Selling price from cost and markup percentage. ROAS Calculator: Return on ad spend. CTR Calculator: Click-through rate.
How to use the CPM Calculator
- Enter ad spend ($) (0 or more).
- Enter impressions (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Ad spend ($) | A number | ≥ 0 |
| Impressions | A number | > 0 |
Formula and method
Formula
CPM = spend ÷ impressions × 1000
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Direct ratio.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Ad spend ($) = 500; Impressions = 100000.
| Result | Value |
|---|---|
| CPM | $5.00 |
Example 2
Inputs: Ad spend ($) = 120; Impressions = 40000.
| Result | Value |
|---|---|
| CPM | $3.00 |
The first line is the headline result (cPM). IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
What CPM tells you
CPM is how advertisers compare the price of reach across channels. At $5.00, every thousand ad views cost $5. It says nothing about whether those views lead to clicks or sales, so pair it with CTR and conversion rate.
Effective CPM
If you pay per click or per action, you can compute the effective CPM by dividing revenue or spend by impressions in the same way. Impressions must be positive.
CPM, CTR and CPC together
$500 for 100,000 impressions is a CPM of $5.00, the cost per thousand impressions. With a CTR of 2%, 1,000 impressions bring 20 clicks, so the cost per click is $5 ÷ 20 = $0.25.
CPM compares exposure cost across channels but says nothing about response.
How the result changes with ad spend
Holding every other input at the first worked example, this table changes only ad spend. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Ad spend | CPM |
|---|---|
| 250 | $2.50 |
| 500 | $5.00 |
| 1000 | $10.00 |
| 2000 | $20.00 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Impressions: entering "0" shows "Impressions must be greater than 0." beside that field and no result.
Choosing between the CPM Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Markup Calculator](/business/markup-calculator/) | cost and markup | Selling price |
| [ROAS Calculator](/business/roas-calculator/) | revenue from ads and ad spend | ROAS |
| [CTR Calculator](/business/ctr-calculator/) | clicks and impressions | CTR |
| [Break-Even Calculator](/business/break-even/) | fixed costs, price per unit and variable cost per unit | Break-even units |
| [Margin Calculator](/business/margin-calculator/) | cost and revenue | Gross margin |
Background: business metrics
Business ratios depend on exactly which costs and revenues you include, so read each page's definition. Two common checks: break-even units = fixed costs ÷ (price − variable cost per unit), so $50,000 of fixed costs with a $10 price and $5 variable cost breaks even at 10,000 units; and net profit margin = net profit ÷ revenue, so $20,000 profit on $100,000 revenue is 20%.
Return on investment ignores time: 20% over five years is far less impressive than 20% in one, so compare returns over the same period.
Assumptions and limitations
- Denominator must be positive
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for impressions to confirm this.
Frequently asked questions
Why is it per thousand?
A single impression costs a fraction of a cent, so pricing is quoted per 1,000.
What is a typical CPM?
Display ads can be a few dollars; video and social can be higher.
How does CPM relate to CTR?
CPC = CPM ÷ (1,000 × CTR).
What does the M in CPM stand for?
Mille, Latin for thousand.
How do I get CPC from CPM?
CPC = CPM ÷ (1,000 × CTR). At $5 CPM and 2% CTR it is $0.25.
What does the CPM Calculator calculate?
Cost per thousand impressions. It returns CPM.
What formula does the CPM Calculator use?
CPM = spend ÷ impressions × 1000. Direct ratio.
What do I need to enter in the cPM Calculator?
You enter Ad spend ($) and Impressions.
How is the result rounded or limited?
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice. Denominator must be positive.
What is an example of a cPM result?
With ad spend ($) 500 and impressions 100000, the cPM is $5.00.
Related calculators
- Markup Calculator — Selling price from cost and markup percentage.
- ROAS Calculator — Return on ad spend.
- CTR Calculator — Click-through rate.
- Break-Even Calculator — Units and revenue needed to cover fixed and variable costs.
- Margin Calculator — Profit, gross margin and markup from cost and revenue.
- ROI Calculator — Return on investment, with optional annualized return.
Sources
- Common definition used on this page. No single authoritative standard defines it, so the exact formula is stated in the formula section above
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.