How to calculate CPM
CPM = (total cost ÷ impressions) × 1,000. A $2,500 campaign that served 400,000 impressions has a $6.25 CPM. Flip the formula to plan: impressions = (budget ÷ CPM) × 1,000.
The M comes from the Latin mille, a thousand. Ad platforms quote CPM because single impressions cost fractions of a cent and are hard to compare.
What moves CPM
Audience competition is the big one. Narrow B2B audiences on LinkedIn often run $30 or more per thousand, while broad consumer audiences on Meta can sit under $10. CPM also climbs in Q4 when retail advertisers bid up inventory, and drops for placements with lower attention.
A low CPM is not automatically good. Cheap impressions that nobody clicks cost more per customer than pricier ones that convert. Pair CPM with CTR and conversion rate to see the full cost of a customer.
CPM vs CPC vs CPA
CPM prices attention, CPC prices clicks and CPA prices outcomes. You can convert between them: CPC = CPM ÷ (CTR × 10), where CTR is a percentage. If your CPM is $12 and your CTR is 0.8%, you are effectively paying $1.50 per click.
Frequently asked questions
What is a good CPM?
It depends on channel and audience. Broad social audiences often land between $5 and $15, while niche B2B audiences can run $30 to $80. Compare against your own history more than against averages.
How do I convert CPM to CPC?
Divide CPM by CTR times 10, with CTR as a percentage. A $12 CPM at 0.8% CTR works out to a $1.50 CPC.
Does CPM include clicks?
No. CPM counts impressions only. Clicks are measured separately through CTR and CPC.
Is my data stored?
No. Everything is calculated in your browser.