What CPM is and why it's the key reach metric

CPM is one of the basic advertising metrics. Let's cover what it is and why it matters in three minutes.

Definition

CPM (cost per mille) is the cost of a thousand ad impressions. "Mille" is Latin for thousand.

Formula: CPM = (placement cost ÷ number of impressions) × 1000.

Example

You paid $400 and got 2,000,000 impressions. CPM = ($400 ÷ 2,000,000) × 1000 = $0.20 per thousand impressions.

Why CPM matters

CPM is a universal "ruler" for comparing channels. Seeding, creators and paid ads deliver different reach at different prices — CPM lets you line them up and see where reach is cheaper.

An important nuance

A low CPM ≠ a cheap customer. Cheap reach of the wrong audience is useless. That's why CPM is always read alongside CPA — the cost of a target action.

Takeaway

CPM shows the price of reach, CPA shows the price of the result. Together they give the full picture. We'll help you build a campaign with a minimal CPM and real returns.