Free Tool

CPM, CPC, CTR & CPA calculator

Fill in whatever you know, from any two or three numbers in your ads dashboard, and it works out everything else. Add more and it checks that your numbers agree with each other.

Enter what you know

Currency

Leave the rest blank. Calculated values appear in grey.

Totals

Ad spend

Impressions

Clicks

Conversions

Rates

CPM

Cost per 1,000 impressions

CPC

Cost per click

CTR (%)

Clicks ÷ impressions

Conversion rate (%)

Conversions ÷ clicks

CPA

Cost per conversion

Try an example:

Results

Enter at least two related numbers, such as spend and clicks.

Ad metrics formulas

Every ad platform reports these numbers slightly differently, but they're all tied together by five simple relationships. If you know enough of them, the rest follow.

CPM = spend ÷ impressions × 1,000
CPC = spend ÷ clicks
CTR = clicks ÷ impressions × 100
Conversion rate = conversions ÷ clicks × 100
CPA = spend ÷ conversions

Planning a campaign from rates

Before launch you rarely know totals, but you can estimate rates. Enter an expected CPM, CTR and conversion rate along with a budget to see roughly how many clicks and conversions it should buy, and what your CPA would be.

Working backwards from a target CPA

If you know the most you can pay for a lead or sale, enter that CPA and your landing page conversion rate. The calculator gives you the maximum CPC you can afford, which is useful for setting bid caps.

Why CTR matters even when you pay per impression

On CPM-billed platforms like Meta and TikTok, your cost per click is CPM ÷ (CTR × 10). Doubling CTR halves your CPC, even though you never paid for the click itself, which is why creative testing is usually the biggest lever on social.

FAQ

Ad metrics questions

Can't find what you need? Ask us directly.

How do I calculate CPM?

CPM (cost per mille) is the cost of 1,000 impressions: CPM = ad spend ÷ impressions × 1,000. Spending $500 for 100,000 impressions is a $5 CPM.

How do I calculate CPC?

CPC (cost per click) = ad spend ÷ clicks. It's also CPM ÷ (CTR × 10) when CTR is a percentage, which is why a better click-through rate makes your clicks cheaper.

How do I calculate CTR?

CTR (click-through rate) = clicks ÷ impressions × 100. 1,500 clicks from 100,000 impressions is a 1.5% CTR.

What is the difference between CPA and CPC?

CPC is what you pay for a click; CPA (cost per acquisition) is what you pay for a conversion such as a lead or sale. CPA = CPC ÷ conversion rate, so a $2 CPC with a 5% conversion rate means a $40 CPA.

What does "these numbers don't add up" mean?

If you enter more values than the calculator needs, it checks that they agree. For example, a $2 CPC with 1,000 clicks must mean $2,000 of spend. If they disagree, one of your numbers is probably from a different date range or campaign.