CPM Calculator
Enter any two of spend, impressions, and CPM. The tool solves for the third and shows the effective CPC and CPA alongside.
CPM
–
Cost per 1,000 impressions
- Spend
- –
- Impressions
- –
- CTR
- –
- Needs clicks
- CPC
- –
- Needs clicks
- Conversion rate
- –
- Needs conversions
- CPA
- –
- Needs conversions
How CPM works, and where it misleads
CPM is the price of attention, not the price of results. It tells you what a thousand impressions cost. It says nothing about whether anyone noticed, clicked, or bought. Two campaigns at the same CPM can differ tenfold in cost per acquisition.
The formula is simple: spend divided by impressions, times 1,000. The useful part is the chain it starts. CPC is CPM divided by 1,000 times click-through rate. CPA is CPC divided by conversion rate. Enter clicks and conversions above and the tool walks the whole chain so you can see which link is expensive.
When a platform quotes a low CPM, ask what CTR it produces. When an agency reports a high CPM, ask what audience it bought. Premium placements with a strong conversion rate routinely beat cheap reach on the number that matters, cost per customer.
Formulas
- CPM
- = Spend ÷ Impressions × 1,000
- Spend
- = CPM × Impressions ÷ 1,000
- Impressions
- = Spend ÷ CPM × 1,000
- CPC
- = CPM ÷ (1,000 × CTR)
- CPA
- = CPC ÷ Conversion rate
Frequently asked questions
How do you calculate CPM?
CPM is total ad spend divided by impressions, multiplied by 1,000. A $5,000 campaign that delivers 400,000 impressions has a CPM of $12.50.
What is a good CPM?
It depends on the channel and audience. Programmatic display often runs in the low single digits, social platforms in the high single digits to mid-teens, and professional networks like LinkedIn frequently above $30. Judge CPM against the cost per click and cost per acquisition it produces, not in isolation.
What is the difference between CPM, CPC, and CPA?
CPM prices impressions, CPC prices clicks, and CPA prices conversions. They are linked: CPC equals CPM divided by 1,000 times CTR, and CPA equals CPC divided by conversion rate. A low CPM with a poor click-through rate can still produce an expensive CPA.
More free tools
Browse all free tools →- CPC Calculator Work out cost per click from spend and clicks, or solve for the budget a click target requires.
- CTR Calculator Calculate click-through rate from impressions and clicks, and see how it compares to channel benchmarks.
- CPA Calculator Calculate cost per acquisition and the break-even CPA your margins can actually support.
Draw it out before the board does.
Monday Brief plus a Thursday deep dive. Free, no paid tier.