Marketing & Paid AdvertisingCPM

Cost Per Mille

What you pay for every 1,000 times your ad is shown. "Mille" is Latin for thousand, so CPM is also called cost per thousand impressions.

1 min readLast updated Apr 2026
Reviewed by Golden Digital·Operator-reviewed ecommerce reference

What you pay for every 1,000 times your ad is shown. "Mille" is Latin for thousand, so CPM is also called cost per thousand impressions.

Use our free Meta Ads Budget Calculator to see the budget your revenue goal needs and how many impressions it buys at your CPM.

Why It Matters

CPM tells you how much it costs just to be seen. When it rises, every click and every sale costs more unless your ad works harder to make up for it. It is often the first place a jump in cost per purchase shows up, especially around busy shopping periods.

Formula

CPM=(Ad Spend/Impressions) × 1,000
Example: CPM = ($600 / 50,000) × 1,000 = $12

Practical Example

Scenario

You spend $600 on a Meta campaign and your ads are shown 50,000 times.

Calculation

CPM = ($600 / 50,000) × 1,000 = $12

Result

Every 1,000 impressions cost you $12. If that rises to $18 next month with the same ads, the same budget buys a third fewer impressions.

In-Depth Explanation

CPM is the price of attention. It is set by the auction: how many advertisers want the same people, at the same time, on the same placement. You pay it whether or not anyone clicks.

Pro Tips

  • 1Compare CPM against your own history for the same audience and placement, not against a number from another brand.
  • 2Expect CPM to rise when more advertisers are bidding, like the run-up to big sale weekends, and plan budgets with that in mind.
  • 3Read CPM next to click-through rate. A higher CPM can still be cheaper per sale if more people click.

Common Mistakes to Avoid

Chasing the cheapest CPM. Cheap impressions often reach people less likely to buy.
Blaming a rise in cost per purchase on the ad when CPM moved first. Check what the auction did before rewriting a creative.
Comparing CPM across platforms as if they were the same thing. An impression means something different on each one.

Frequently Asked Questions

Cost per mille, where mille is Latin for thousand. It is the price you pay for 1,000 impressions of your ad.

Usually because more advertisers are competing for the same people, which happens around holidays and sale periods. A narrow audience, a tired creative or a low quality ranking from the platform can also push it up.

Related Tools

Meta Ads Budget Calculator

Related Terms

Cost Per Click
CPC

The average amount you pay each time someone clicks your ad. It is your ad spend divided by the number of clicks.

Click-Through Rate
CTR

The share of people who saw your ad and clicked it: clicks divided by impressions, shown as a percentage.

Return On Ad Spend
ROAS

The revenue generated for every dollar spent on advertising.

Creative Fatigue

The decline in ad performance when audiences see the same creative too frequently.

Broad Targeting

Running ads with minimal audience restrictions, relying on platform algorithms.

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