CPM Calculator

How do you use the CPM calculator?

Enter spend and impressions to get CPM. Add clicks, purchases, price and variable costs to see CPC, CPA and break-even CPM from the same form.

1. Copy amount spent and impressions from your ad account for one date range.
2. Optional: add clicks for CPC and purchases for CPA.
3. Optional: add your price per order and variable costs per order (product, shipping, payment fees, packaging) for break-even CPA and break-even CPM.
4. Share the result by copying the page link. Only the numbers are stored in it.

What is the CPM formula?

CPM is spend divided by impressions, multiplied by 1,000. Meta defines it as the average cost of 1,000 impressions, calculated the same way.

CPM = spend ÷ impressions × 1,000
CPC = spend ÷ clicks
CPA = spend ÷ purchases
Break-even CPA = price − variable costs per order
Break-even CPM = break-even CPA × (purchases ÷ impressions) × 1,000

CPA follows Meta's cost per website purchase: spend divided by purchases. Break-even CPA is your contribution margin per order, the most you can pay for one order before it loses money (the Amazon Ads "Ads Math" guide uses the same idea as "profit per sale").

Why does this CPM calculator show break-even CPM?

Most CPM calculators stop at the CPM. On paid social, the CPM is mostly set by the auction, so the useful question is how high it can go before your orders stop paying for themselves.

Break-even CPM answers that. It takes the most you can pay per order and multiplies it by how often an impression turns into an order. If your actual CPM is below the break-even CPM, each order covers its ad cost at your current conversion rate. If it is above, either the CPM has to come down or more impressions have to turn into orders.

Worked example

Enter these numbers in the calculator above (example numbers, in any currency):

The tool shows the same results:

In this example the actual CPM (12.50) is below the break-even CPM (15.00), and the actual CPA (50) is below the break-even CPA (60). At this price and conversion rate, each first order covers its ad cost with 10 of margin left. The two comparisons always agree, because both come from the same inputs.

The gap also shows how much room there is. CPM could rise by 2.50 before orders stop covering their ad cost, as long as the conversion rate holds. If CPM goes above break-even, one of three things has to change: a lower CPM, more purchases from the same impressions, or a higher margin per order. The break-even ROAS calculator shows the same limit as a ROAS figure.

Why does CPM change on paid social?

CPM comes out of the ad auction, so it moves with the audience, placement, country and time of year you buy. Track it next to creative metrics, so you can see whether a change in cost arrives at the same time as a change in how people respond to the ad. If CPM rises on an ad that has run for weeks while its CTR falls, check for creative fatigue. For video ads, the hook rate calculator shows whether the opening seconds still stop people.

What are the limits of this calculator?

The calculator divides the totals you enter. It does not know your account, your attribution setting or your margins beyond what you type.

• No benchmark CPMs. CPMs vary by country, audience, placement and season, so the tool shows no "good" or "bad" verdict.
• First order only. Break-even CPM assumes each customer orders once. If customers reorder, the LTV calculator shows how much more one customer is worth.
• Platform-attributed purchases. Purchases come from the ad platform's attribution, which may not match your store.
• Same period for every input. Mixing a 7-day spend with a 30-day purchase count gives a wrong CPA and break-even CPM.

Related tools and glossary entries

See the CPM glossary entry for the definition, and the CPA and contribution margin entries for the break-even inputs. The ad metrics calculator adds CTR, conversion rate and ROAS to the same form, and the CTR calculator and CPA calculator cover those metrics on their own. All free tools are on the tools page.

If you want more creative to test against your break-even numbers, see how Anglr works for brands.