CPM (Cost per Mille)

Metric

CPM is the cost of displaying an ad one thousand times (mille is Latin for thousand).

Layman Explanation & Analogy

CPM is the industry standard price for eyeballs. If an ad network charges a $20 CPM, it means you pay $20 for every 1,000 times your ad appears on someone’s screen.

Mathematical Formula

CPM = (Ad Spend ÷ Total Impressions) × 1,000

Worked real-world example

An ad campaign spends $500 and is displayed 25,000 times. CPM = ($500 ÷ 25,000) × 1,000 = $20.

What people get wrong & common traps

High CPMs are common in competitive, high-intent audiences (like B2B executives or enterprise buyers). A $100 CPM targeting CTOs can be vastly more profitable than a $3 CPM targeting broad entertainment audiences.

Related terms