CPM calculator.
Fill in any two of spend, impressions and CPM: we'll work out the third. Get your cost per 1,000 impressions, or the budget and reach needed to hit a target.
CPM = (ad spend ÷ impressions) × 1,000. Planning a campaign? Check your ROAS target too.
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How to calculate CPM.
CPM = (ad spend ÷ impressions) × 1,000. CPM stands for cost per mille: the cost of 1,000 ad impressions. £2,000 of spend for 500,000 impressions is a £4.00 CPM.
The same formula works in reverse, which is why this calculator can solve for whichever value is missing:
- Impressions = spend ÷ CPM × 1,000: £3,000 at a £6 CPM buys 500,000 impressions.
- Spend = impressions × CPM ÷ 1,000: 1,000,000 impressions at a £5 CPM costs £5,000.
What affects CPM?
- Competition: CPMs usually rise in busy periods such as Q4 and Black Friday, when more advertisers bid for the same people.
- Audience: small, high-value or tightly targeted audiences tend to cost more to reach.
- Platform, placement and format: video, connected TV and premium placements typically cost more per impression than standard display.
- Creative: ads people engage with are often rewarded with more efficient delivery.
CPM is a cost, not a goal
A cheap CPM means nothing if those impressions don't lead to sales. Use CPM to plan reach and budget, then judge performance on outcomes with the CPA and ROAS calculators. For awareness at scale, see programmatic and paid social.
Keep calculating.
CPA calculator
Work out cost per acquisition, conversion rate and CPC, and the maximum you can bid per click to hit a target CPA.
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Open tool →CPM questions.
01What is CPM?
CPM means cost per mille, the cost per 1,000 ad impressions. CPM = (ad spend ÷ impressions) × 1,000.
02What is a good CPM?
It varies hugely by platform, audience, format and season. Compare CPMs within the same channel and audience rather than against a universal benchmark, and remember a low CPM is worthless if it doesn’t convert.
03How do I lower my CPM?
Broaden or refine targeting, improve creative relevance and engagement, avoid over-narrow audiences, and test placements. But optimise for outcomes (leads/revenue), not CPM alone.
Low CPMs are easy; profitable reach is the hard part. See how our media management approaches it.