CPC to CPA Calculator
Turn cost per click and conversion rate into cost per acquisition – or work backwards to the maximum CPC or the conversion rate a target CPA needs.
What do you want to calculate?
Enter both values to see the result.
How CPC, conversion rate and CPA fit together
Every conversion costs as many clicks as it takes to get one. With a 2% conversion rate you need 50 clicks per conversion, so the conversion costs 50 times the average CPC. The calculator works with any two of the three numbers and finds the third.
Formulas
Worked examples
1. CPA from campaign data
A Search campaign has an average CPC of €0.80 and converts 2% of clicks.
2. Maximum CPC for a target
A lead is worth paying at most €40 for, and the landing page converts 2.5% of visitors.
3. Is the target realistic?
Clicks in a competitive niche cost €3 and the target CPA is €60.
If the site converts 2%, the target needs either cheaper clicks, a better landing page or a higher CPA.
Practical notes
- Use real averages, not bids. The actual average CPC is usually lower than the maximum CPC you bid.
- Segment before you average. Brand campaigns convert far better than generic ones, and mobile often converts worse than desktop. One account-wide rate can hide both.
- Mind the conversion definition. A CPA for leads, for purchases and for "all conversions" in Google Ads are three different numbers.
- For e-commerce, ROAS often beats CPA. When order values vary a lot, compare results with your break-even ROAS instead.
Frequently asked questions
How do I calculate CPA from CPC?
Divide the cost per click by the conversion rate. With a €0.80 CPC and a 2% conversion rate, CPA = 0.80 ÷ 0.02 = €40.
What is the maximum CPC I can afford?
Multiply your target CPA by your conversion rate. With a €40 target CPA and a 2% conversion rate, you can pay up to €0.80 per click.
Which conversion rate should I use?
Use the rate of the campaign or keyword you are planning for, over a period with enough conversions to be stable. Account averages hide big differences between brand and non-brand traffic.