CPM (cost per mille)
CPM is the cost of one thousand ad impressions, calculated as spend divided by impressions times 1,000 — the base unit for pricing reach.
Mille is Latin for thousand, so CPM prices exposure in bulk: showing an ad a thousand times. It is the natural metric for awareness and reach campaigns, where being seen by the right audience is the goal.
CPM prices attention, not results. A low CPM feeding a weak click-through rate can produce a worse cost per click than a higher CPM with strong creative, so CPM is best read as one link in the chain that ends at cost per acquisition.
Newsletter
Learn this stuff by email
New definitions, tools, and explainers when I publish them. No spam, unsubscribe anytime.