Paid Ads

CPM (Cost Per Mille)

CPM is the cost per 1,000 impressions. It varies by audience, placement, seasonality, and competition.

Written by MetricKit EditorialReviewed by MetricKit Editorial ReviewUpdated 2026-01-23
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Definition

CPM is the cost per 1,000 impressions. It varies by audience, placement, seasonality, and competition.

Formula

CPM = (ad spend / impressions) * 1000

Example

If you spent $1,200 for 100,000 impressions, CPM = ($1,200 / 100,000) * 1000 = $12.

How to use it

  • Use CPM with CTR to estimate CPC, then with CVR to estimate CPA.
  • Judge CPM against your economics, not as a standalone KPI.

Measured as

CPM = (ad spend / impressions) * 1000

Operator takeaway

  • Use CPM with CTR to estimate CPC, then with CVR to estimate CPA.
  • Judge CPM against your economics, not as a standalone KPI.
  • Use CPM (Cost Per Mille) only inside a stable attribution rule, conversion definition, and time window so campaign comparisons stay honest.
  • If performance changes, check whether the metric moved for a real business reason or because the measurement setup changed underneath you.

Next decision

  • Quantify the impact with Break-even CPM Calculator if you need to turn the definition into an operating assumption.
  • Read CPM (Cost Per 1,000 Impressions): definition, formula, and how to calculate if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.

Where to use this on MetricKit

Calculators

  • Break-even CPM Calculator: Compute break-even and target CPM from CTR, CVR, AOV, and contribution margin assumptions.
  • Paid Ads Funnel Calculator: Model CPM -> CTR -> CVR to estimate CPC, CPA, ROAS, and profit per 1,000 impressions (with margin and variable costs).
  • Break-even CTR Calculator: Compute the CTR required to break even (and hit a target) given CPM, CVR, AOV, and contribution margin.
  • Break-even CVR Calculator: Compute the CVR required to break even (and hit a target) given CPM, CTR, AOV, and contribution margin.

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