CPM (Cost Per Mille)
Also known as: Cost Per Thousand Impressions, Cost Per Mille
CPM is the cost to show your ad 1,000 times, calculated as total spend divided by impressions, multiplied by 1,000.
What it actually means
CPM stands for cost per mille, where mille is Latin for thousand. It measures how much you pay for 1,000 ad impressions, regardless of whether anyone clicks. On Meta, CPM is set by auction: the more advertisers competing for the same audience, the higher it climbs. CPM is the base layer of nearly every other cost metric — a high CPM inflates your cost per click and cost per lead even when your ad is performing well. Tracking it over time tells you whether rising costs come from competition and seasonality or from your own targeting and creative choices.
Spending $200 to reach 40,000 impressions is a $5 CPM ($200 ÷ 40,000 × 1,000).
For a local business, CPM is usually low because you target a small radius with few competing advertisers — but it spikes during holidays when big brands flood the same feed. Watching CPM helps you time campaigns and avoid overpaying in crowded weeks.
Related terms
CPC is the average amount you pay each time someone clicks your ad, calculated as total spend divided by clicks.
CPL is the average cost to generate one lead, calculated as total ad spend divided by the number of leads collected.
An impression is counted each time your ad is displayed on screen, regardless of whether the same person sees it more than once.
Reach is the number of unique people who saw your ad at least once during a given time period.
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