EStore Tools

CPM Calculator

Enter spend, impressions, clicks and conversions once, and see CPM, CPC, CTR, CVR and CPA together, so you can see how they connect.

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Your numbers

$
impressions
clicks
orders

Used to estimate the budget needed at this CPA.

orders

Your result · updates as you type

CPM (cost per 1,000 impressions)

$4.00

$1,000 bought 250,000 impressions, 3,000 clicks and 60 conversions.

CPC (cost per click)
$0.33
CTR (click-through rate)
1.2%
CPA (cost per conversion)
$16.67

These four numbers are the same funnel seen from different angles: CPM × (clicks ÷ impressions) ÷ 1,000 gives you CPC, and CPC ÷ CVR gives you CPA. A platform quoting a low CPM with a weak CTR can end up with a worse CPA than a higher CPM with a strong one.

Breakdown

Ad spend
$1,000
Impressions
250,000
CPM
$4.00
Clicks
3,000
CTR (clicks ÷ impressions)
1.2%
CPC
$0.33
Conversions
60
CVR (conversions ÷ clicks)
2%
CPA
$16.67
Budget for 100 conversions at this CPA
$1,667

One funnel, five numbers

CPM, CPC, CTR, CVR and CPA all describe the same campaign from a different angle. Enter spend alongside impressions, clicks and conversions, and the calculator works out every metric at once, so you can see how a change in one moves the others.

CPM = spend ÷ impressions × 1,000 CPC = spend ÷ clicks CTR = clicks ÷ impressions CPA = spend ÷ conversions CVR = conversions ÷ clicks

Example: the default numbers

Spend
$1,000
Impressions
250,000
Clicks
3,000
Conversions
60

CPM is $4.00, CTR is 1.2%, CPC is $0.33, CVR is 2%, and CPA is $16.67.

Why CPM alone is misleading

A campaign with a low CPM but a weak CTR and CVR can end up with a worse CPA than a campaign with a higher CPM but strong engagement. Before switching platforms or audiences to chase a cheaper CPM, check where CPA actually lands.

  • Budgeting forward. Use the CPA from this calculator with the ad budget calculator to work out spend for a revenue target.
  • Bid caps. Feed CPC into the max CPC calculator to see if it's affordable given your margin.

Questions people ask

What is CPM in advertising?

Cost per mille, or cost per 1,000 impressions: what you pay for every thousand times your ad is shown, regardless of clicks or conversions.

How do you convert CPM to CPC?

Divide CPM by 1,000, then divide by your click-through rate: CPC = (CPM ÷ 1,000) ÷ CTR. This calculator does the division directly from spend, impressions and clicks.

What's a good CPM?

It varies enormously by platform, placement and season, so there's no single good number. Compare your own CPM over time and against CPA, which is what actually matters.

Why is my CPA high even with a low CPM?

A low CPM with a weak click-through or conversion rate can still produce an expensive CPA. Check CTR and CVR before assuming the CPM itself is the problem.

Related tools

Ad Budget CalculatorWork backwards from a revenue target through orders and sessions to the ad budget you actually need.Max CPC CalculatorFind the highest cost per click you can afford at your conversion rate and margin, before it eats into the profit you want to keep.ROAS CalculatorWork out return on ad spend, then see your own break-even ROAS line instead of a generic benchmark.Facebook Ads Budget CalculatorSet a daily budget sized to clear Meta's learning phase and hit your target cost per purchase, with a cushion built in.

Want this builtinto your store?

I'm Emmanuel, a Shopify and WooCommerce developer. If this tool pointed at something you'd rather have fixed for you (a faster store, cleaner product data, a migration, a custom feature), send me a note.

Emmanuel Asika

Emmanuel Asika

Shopify & WooCommerce developer, Dublin

I build and fix online stores: new builds, migrations, speed, SEO and the custom bits apps can't do.

hello@emmanuelasika.com
See my work

Last reviewed 30 September 2026.