How do I calculate CPM?

Divide the ad cost by the number of impressions and multiply by 1,000. $2,500 for 200,000 impressions is a $12.50 CPM.

What does CPM stand for?

Cost per mille, Latin for thousand: the cost of 1,000 ad impressions. It is the usual way to price display, video, social and newsletter ads.

How do I calculate CTR?

Divide clicks by impressions and multiply by 100. 1,600 clicks from 200,000 impressions is a 0.8% click-through rate.

How do I calculate CPC from CPM?

CPC = CPM ÷ (CTR × 1,000). A $12.50 CPM with a 0.8% CTR gives $12.50 ÷ 8 = $1.56 per click, because 1,000 impressions bring 8 clicks.

How do I calculate ROAS?

Divide the revenue the ads brought in by what you spent on them. $10,000 of revenue from $2,500 of ads is a ROAS of 4, often written 4x or 400%.

What is break-even ROAS?

The ROAS at which gross profit exactly pays for the ads: 1 ÷ gross margin. At a 40% margin you need 2.5; anything below that loses money even though revenue exceeds ad spend.

How do I calculate CPA?

Divide ad cost by conversions. $2,500 that brings 48 sign-ups or sales is a $52.08 cost per acquisition. Compare it with the gross profit one customer brings you.

How are newsletter sponsorships priced?

Usually as a CPM, either per 1,000 subscribers on the list or per 1,000 opens. Subscriber pricing costs more for the same rate, by a factor of 1 ÷ open rate.

Free calculator

CPM calculator with CPC, CTR, CPA and ROAS

Enter any two of cost, impressions and CPM to get the third, add clicks and conversions for CTR, CPC and CPA, check ROAS against your break-even ROAS, and price a newsletter placement per subscriber or per open.

Updated October 27, 2026

Your numbers

Work out

Ad spend

Impressions

Clicks

Conversions

Cost per 1,000 impressions. Clicks and conversions are optional.

Runs in your browser. Nothing you type is sent or stored.

CPM

$12.50

You pay $12.50 for every 1,000 impressions.

Ad spend: $2,500.00
Impressions: 200,000
CTR: 0.8%
CPC: $1.56
Conversion rate: 3%
CPA: $52.08

Every 1,000 impressions cost $12.50, and 0.8% of them turn into clicks at $1.56 each.

Quick answer

How do you calculate CPM?

CPM = ad cost ÷ impressions × 1,000: the price of 1,000 impressions. $2,500 for 200,000 impressions is a $12.50 CPM. Turn it around for the others: cost = CPM × impressions ÷ 1,000, impressions = cost ÷ CPM × 1,000. With 1,600 clicks, CTR is 1,600 ÷ 200,000 = 0.8% and CPC is $2,500 ÷ 1,600 = $1.56.

How to use the CPM calculator

Pick a mode
CPM & CTR for campaign maths, ROAS to see whether ads pay at your margin, Newsletter to price a sponsorship.
Choose what to work out
In CPM & CTR, pick CPM, cost or impressions and enter the other two. Add clicks and conversions if you have them.
Read the result
See the missing number with CTR, CPC, conversion rate and CPA, or ROAS against your break-even ROAS.
Share it
Copy the link to send the exact numbers to a client or a sponsor. Nothing is stored on our side.

How the calculator works

CPM stands for cost per mille, the cost of 1,000 impressions: cost ÷ impressions × 1,000. Because the three numbers are tied by one formula, any two give the third.

Click-through rate is clicks ÷ impressions. Cost per click is cost ÷ clicks. Conversion rate is conversions ÷ clicks, and cost per acquisition (CPA) is cost ÷ conversions. Ad platforms count clicks, views and conversions their own way, so use one platform’s numbers for one calculation.

ROAS is revenue ÷ ad spend. Revenue is not profit: only the gross margin on that revenue is left to pay for the ads. Break-even ROAS is therefore 1 ÷ gross margin, and the most you can pay for one order is the order value × gross margin.

Newsletters quote CPM two ways: per 1,000 subscribers on the list or per 1,000 opens. Opens are subscribers × open rate, so at a 45% open rate the same rate costs 2.2 times more per subscriber than per open. Open counts also run high, because Apple Mail Privacy Protection loads email content in the background whether or not the reader engages.

Formula

CPM = cost ÷ impressions × 1,000
CTR = clicks ÷ impressions × 100
CPC = cost ÷ clicks
CPA = cost ÷ conversions
ROAS = revenue ÷ ad spend
Break-even ROAS = 1 ÷ gross margin

Worked example

$2,500 buys 200,000 impressions: CPM = $2,500 ÷ 200,000 × 1,000 = $12.50.
1,600 clicks: CTR = 1,600 ÷ 200,000 = 0.8%, CPC = $2,500 ÷ 1,600 = $1.56.
48 conversions: conversion rate = 48 ÷ 1,600 = 3%, CPA = $2,500 ÷ 48 = $52.08.
They bring $10,000 of revenue: ROAS = $10,000 ÷ $2,500 = 4.
At a 40% gross margin, break-even ROAS is 1 ÷ 0.40 = 2.5, so the ads earn $10,000 × 0.40 − $2,500 = $1,500 of gross profit.

CPM vs CPC vs CPA

Metric	You pay for	Formula	Use it to
CPM	1,000 impressions	Cost ÷ impressions × 1,000	Compare the price of reach across channels
CPC	One click	Cost ÷ clicks	Compare the price of traffic
CPA	One conversion	Cost ÷ conversions	Compare with what a customer is worth
ROAS	Nothing: it is a ratio	Revenue ÷ ad spend	Check that ads pay back at your margin

Break-even ROAS: why 2x can lose money

A ROAS of 2 sounds like doubling your money, but ROAS counts revenue, not profit. At a 40% gross margin, $2 of revenue leaves $0.80 to pay for $1 of ads, a loss. Break-even ROAS is 1 ÷ gross margin: 2.5 at 40%, 1.25 at 80%. Software with high gross margins can run ads at a lower ROAS than a store selling physical goods.

Newsletter CPM: per subscriber or per open

Some newsletters price sponsorships on list size, others on opens and label it CPM/opens. A 20,000-subscriber list at a $30 CPM costs $600 per send priced on subscribers, or $270 priced on its 9,000 opens. Ask which one a quote uses, and remember that open counts include machine opens from Apple Mail Privacy Protection.

CPM questions

How do I calculate CPM?: Divide the ad cost by the number of impressions and multiply by 1,000. $2,500 for 200,000 impressions is a $12.50 CPM.
What does CPM stand for?: Cost per mille, Latin for thousand: the cost of 1,000 ad impressions. It is the usual way to price display, video, social and newsletter ads.
How do I calculate CTR?: Divide clicks by impressions and multiply by 100. 1,600 clicks from 200,000 impressions is a 0.8% click-through rate.
How do I calculate CPC from CPM?: CPC = CPM ÷ (CTR × 1,000). A $12.50 CPM with a 0.8% CTR gives $12.50 ÷ 8 = $1.56 per click, because 1,000 impressions bring 8 clicks.
How do I calculate ROAS?: Divide the revenue the ads brought in by what you spent on them. $10,000 of revenue from $2,500 of ads is a ROAS of 4, often written 4x or 400%.
What is break-even ROAS?: The ROAS at which gross profit exactly pays for the ads: 1 ÷ gross margin. At a 40% margin you need 2.5; anything below that loses money even though revenue exceeds ad spend.
How do I calculate CPA?: Divide ad cost by conversions. $2,500 that brings 48 sign-ups or sales is a $52.08 cost per acquisition. Compare it with the gross profit one customer brings you.
How are newsletter sponsorships priced?: Usually as a CPM, either per 1,000 subscribers on the list or per 1,000 opens. Subscriber pricing costs more for the same rate, by a factor of 1 ÷ open rate.

Cite this tool

Free to link and quote. Use this reference:

SaaSCity, "CPM Calculator", October 27, 2026. https://saascity.io/free-tools/cpm-calculator