The instrument
What does CPM stand for?
By Oliver Wakefield-Smith · updated July 2026
The short answer
CPM stands for cost per mille. Mille is Latin for thousand, so CPM is the cost of 1,000 ad impressions. Google's ad documentation uses exactly this expansion. Some markets say CPT, cost per thousand; it is the same metric wearing an English suffix.
Why Latin survived in a rate card
The metric predates the internet. Print and broadcast media sold audiences by the thousand, and the Roman numeral M (mille) was already the accounting shorthand for 1,000. When display advertising went digital in the 1990s, the unit came along unchanged. Merriam-Webster confirms the etymology; your finance team confirms the habit.
CPM vs CPT
UK and some European buyers occasionally write CPT, cost per thousand. Same formula, same number, different letters. If a rate card quotes both, they should match to the cent; if they do not, ask which impression definition each uses before you sign anything.
Not the CPM you meant?
Everything else
Certified Property Manager, critical path method, counts per minute, cost per message. Each routed properly on the meanings page.
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