CPM and CPC Calculator
Cost per thousand impressions, cost per click and click-through rate — all three from the same three numbers.
These three measures are linked: CPM is what you pay for reach, CTR is how well the creative converts that reach into clicks, and CPC is what a click therefore costs.
How the cpm and cpc calculator works
These three measures are linked: CPM is what you pay for reach, CTR is how well the creative converts that reach into clicks, and CPC is what a click therefore costs. Any two determine the third.
That relationship is the useful part. A rising CPC can mean the auction got more expensive or the creative got worse, and the three together tell you which: if CPM held steady and CTR fell, the creative is the problem, not the market.
CPM is quoted per thousand impressions because individual impressions are worth fractions of a cent, and a per-unit figure would be unreadable.
Formula: CPM = spend/impressions × 1000; CTR = clicks/impressions; CPC = spend/clicks
Worked examples
| Inputs | CPM | Note |
|---|---|---|
| 5,000 spend, 800k impressions, 6,400 clicks | £6.25 | CPM 6.25, CPC 0.78, CTR 0.8% |
| A high-CTR campaign | £25.00 | CTR 3.2% |
| No clicks | £6.25 | CPM only |
FAQFrequently asked questions
What is CPM?
Cost per thousand impressions — the M is the Roman numeral for a thousand, not "million".
How are CPM, CPC and CTR related?
CPM equals CPC × CTR × 1000. Any two give the third, which is how you tell an expensive auction from weak creative.
What is a good CTR?
Display advertising often runs 0.05% to 0.5%; search advertising on branded terms can exceed 10%. Compare within a channel only.
Why did my CPC rise?
Either the auction got more competitive, which shows as a higher CPM, or the creative stopped earning clicks, which shows as a lower CTR.
What is CPA?
Cost per acquisition — spend divided by conversions, which is the figure that actually decides whether a campaign works.
Where these figures come from
- Interactive Advertising Bureau — measurement guidelines — the impression and viewability definitions CPM depends on
- Advertising Standards Authority — the UK advertising regulator
Last checked: September 2026. These are standard industry definitions; where platforms disagree, the page says so.