CPM Calculator — Cost, Impressions and CPM in Any Direction

CPM is the cost of 1,000 impressions. Cost, impressions and CPM form a triangle — give any two and the third is worked out for you, marked as computed. Below, plan reach from frequency and expected impressions from a budget. Everything runs in your browser.

Solve for

The field you solve for is locked and filled in for you — edit the other two.

Campaign cost ($)

Impressions

CPM — cost per 1,000 impressions ($)

Computed

Reach & frequency helper

Impressions

Average frequency (times each person sees it)

Reach = impressions ÷ frequency — how many different people those impressions amount to.

Budget planner

Budget ($)

Target CPM ($)

Expected impressions = budget ÷ target CPM × 1,000.

The maths: CPM = cost ÷ impressions × 1,000. Cost = CPM × impressions ÷ 1,000. Impressions = cost ÷ CPM × 1,000.

Cost per 1,000 impressions (CPM)

—

Campaign cost

—

Impressions

—

CPM

—

Reach — unique people

Reach

—

Impressions per person (frequency)

—

Reach assumes the frequency is an even average — real campaigns show ads unevenly, so some people see more and others fewer.

Budget planner — expected impressions

Expected impressions

—

Budget at target CPM

—

A planning estimate only: the CPM you actually pay is set by the auction, your targeting and your creative, so real impressions can land well above or below this.

CPM

—

Solve the cost, impressions and CPM triangle in any direction, plus reach from frequency and a budget-to-impressions planner.

UNDERSTAND YOUR RESULTS

CPM Calculator — Cost, Impressions and CPM in Any Direction guide

Solve the advertising triangle in any direction — CPM from cost and impressions, cost from CPM and impressions, or impressions from cost and CPM — then plan reach from frequency and the impressions a budget buys at a target CPM.

How to use this tool

Pick what to solve for at the top: CPM, campaign cost or impressions. The solved field is locked, marked Computed, and filled in for you.
Enter the other two values and the third updates live — change either input and the computed field follows.
Use the reach helper below: enter impressions and the average frequency (how many times each person sees the ad) to get reach, the number of different people reached.
Use the budget planner: enter a budget and the CPM you expect to pay to see the impressions that budget should buy.
Watch for dashes instead of numbers when a divisor is zero or a field is empty — that is deliberate, so a half-filled form never shows a misleading figure.

A worked example

A campaign costs $500 and delivers 250,000 impressions. CPM = $500 ÷ 250,000 × 1,000 = $2.00 exactly. Run it the other way: at a CPM of $4, a $1,000 budget buys $1,000 ÷ $4 × 1,000 = 250,000 impressions. And if those 250,000 impressions come at an average frequency of 2.5 — each person seeing the ad two or three times — reach is 250,000 ÷ 2.5 = 100,000 different people.

What you can do with this tool

Solve for CPM from campaign cost and impressions, with the computed field locked and clearly marked.
Solve in reverse for campaign cost from CPM and impressions.
Solve in reverse for impressions from campaign cost and CPM.
Work out reach from impressions and average frequency — how many different people your ads amount to.
Plan a budget: enter a budget and a target CPM to see the impressions it should buy.
See cost, impressions and CPM side by side, updating live as you type.
Show a dash instead of NaN or Infinity whenever a field is empty or a divisor is zero.

How it works

CPM means cost per mille — the price of 1,000 impressions. The three forms are one formula rearranged: CPM = cost ÷ impressions × 1,000; cost = CPM × impressions ÷ 1,000; impressions = cost ÷ CPM × 1,000. Reach = impressions ÷ frequency, where frequency is the average number of times one person is shown the ad. The budget planner applies the impressions form directly: budget ÷ target CPM × 1,000.

Frequently asked questions

What does CPM stand for?

Cost per mille — mille is Latin for thousand — so CPM is what 1,000 impressions cost. It is the standard way display, social and video ads are priced and compared, even when you ultimately care about clicks or sales.

How do I calculate CPM by hand?

Divide the campaign cost by the impressions, then multiply by 1,000. A $500 campaign with 250,000 impressions: 500 ÷ 250,000 = 0.002 per impression, × 1,000 = a $2.00 CPM. This calculator does the same maths in all three directions.

What is a good CPM?

It varies too much by platform, audience and country for a single answer: broad social campaigns might clear at a few dollars, while narrow B2B or LinkedIn audiences can cost ten times that. A CPM is only good or bad against what those impressions return — compare it with your click and conversion costs, not with a benchmark table alone.

What is the difference between reach and impressions?

Impressions count every time the ad is shown, including repeats to the same person. Reach counts different people. 250,000 impressions at a frequency of 2.5 means about 100,000 people saw the ad an average of two and a half times each.

Why does the computed field change when I switch what to solve for?

Because the triangle has three sides and the solver always fills the one you picked. Switching the solve-for locks that field and treats the other two as your inputs — the values carry over, so you can flip direction on the same campaign without retyping.

Why do I see a dash instead of a number?

A dash means the maths cannot be done honestly yet: a needed field is empty, or you would be dividing by zero — impressions of 0, or a CPM or frequency of 0. Fill in a real value and the result appears; the calculator never shows NaN or Infinity.