CPA Calculator
CPA (cost per acquisition) is ad spend divided by conversions — what you pay for one purchase, lead or signup.
What is CPA?
CPA is the main daily decision number in paid ads. Compare it with your break-even CPA: below it you make money, above it you lose.
How to use the CPA calculator (formula)
What each field means
- Ad spend — Total ad spend.
- Conversions — Purchases, leads or signups from that spend.
Worked example
Using these numbers: ad spend $5,000, conversions 200.
The cost per acquisition is $25.00.
- Conversions per 1,000 spend: 40
What is a good CPA?
A good CPA is comfortably below your break-even CPA — usually 25–40% lower. Absolute numbers vary by price, category and country.
Tips to improve your result
- Define one conversion per campaign.
- Judge new ads after enough conversions, not after one day.
- Better landing pages lower CPA as much as better ads.
- Track CPA per audience and creative.
Frequently asked questions
What is the CPA formula?
CPA = ad spend ÷ number of conversions.
CPA vs CAC — what is the difference?
CPA counts any conversion from ads; CAC counts all costs to win a new customer.
How can I reduce CPA?
Improve creative, targeting, offer and landing page conversion rate.
How does CPA affect profit?
Every unit of CPA comes straight out of profit per order.
You might also need
ROAS CalculatorReturn on ad spend from revenue and spend.
Break-even ROAS CalculatorThe minimum ROAS your margin allows.
Want help improving these numbers?
Book a free consultation and I'll review your store and ads.