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Cost per mille

What is CPM (cost per mille)?

CPM (cost per mille) is what an advertiser pays for 1,000 ad impressions, the standard price of reach on social and display ads.

Formula

CPM = ad spend ÷ impressions × 1,000

Spend $500 for 40,000 impressions and your CPM is $12.50: each time the ad was shown 1,000 times, it cost $12.50.

Work out yours with the CPM calculator.

A real store example

Alo new arrivals page: over 500 Meta ads linked here.

Alo points this many ads at a collection of new leggings, sets and hoodies rather than at one product. Each impression costs the same either way; a page with many fresh products gives each paid view more chances to find something the shopper wants.

Open the pageSee their ads

How to improve CPM on your store

  1. Refresh creative before it tires

    Platforms charge more to show ads people scroll past. New hooks and formats keep the ad relevant and the CPM down.

  2. Give the algorithm room

    Narrow audiences compete for the same few people. Broader targeting usually lowers CPM and lets the platform find buyers.

  3. Judge CPM by what it sells

    A cheap CPM that never converts costs more than an expensive one that does. Track CPM next to orders, not alone.

Ask Replo: "show CPM, CTR and orders by campaign this month".

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CPM questions

What does CPM stand for?
CPM stands for cost per mille, mille being Latin for thousand. It's the price of 1,000 ad impressions, and it's how Meta, TikTok and most display networks price ads bought for reach.
Why do CPMs rise in November?
More advertisers bid for the same shoppers before Black Friday and the holidays, so the auction gets more expensive. Plan for higher CPMs in the fourth quarter and make sure each visit converts well enough to pay for them.
Is a low CPM good?
Only if the impressions turn into sales. Low CPMs often come from audiences that rarely buy. Compare cost per order across campaigns instead of CPM alone.

Related terms

Browse the glossary

CTR

CTR (click-through rate) is the share of people who see an ad or link and click it: clicks divided by impressions.

CPC

CPC (cost per click) is the average amount paid each time someone clicks an ad: ad spend divided by clicks.

ROAS

ROAS (return on ad spend) is the revenue an ad campaign brings in for every dollar spent on it: revenue from ads divided by ad spend.

CPA

CPA (cost per acquisition) is the ad spend it takes to win one conversion, such as a purchase or signup: ad spend divided by conversions.

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