Free marketing calculator · Media cost
Cost Per Thousand Impressions (CPM) Calculator
Calculate CPM to understand what you are paying for every thousand advertising impressions.
What is CPM?
CPM standardises media cost around 1,000 impressions. It is widely used for display, social and other impression-based advertising because it makes the cost of reaching an audience easier to compare across campaigns and periods.
CPM = Advertising spend ÷ Impressions × 1,000
Worked example
If a campaign spends £8,000 and serves 2,000,000 impressions, its CPM is £4.00. That does not mean each thousand impressions has equal value: audience quality, viewability, placement, frequency and creative context all matter.
How to use CPM
CPM is an exposure-cost metric. It becomes more informative when paired with CTR and downstream conversion data. A higher CPM can still make commercial sense if it buys a more valuable audience; a low CPM can be poor value if the impressions rarely lead to meaningful action.
Need the wider picture?
See how CPM interacts with clicks, leads, conversions, revenue and ROAS across the full campaign funnel.
Frequently asked questions
Does a lower CPM mean better advertising?
No. CPM measures the cost of exposure, not the quality of the audience or the business result.
Why is it called CPM?
The M comes from the Roman numeral for one thousand. CPM therefore means cost per thousand impressions.