CPA calculator
Enter your ad spend and the orders it brought in to get your cost per acquisition. Add order value and margin to see whether the first order pays for it.
Formula
CPA = ad spend ÷ conversions
For a store, a conversion is usually an order. Break-even CPA = average order value × gross margin, the gross profit one order leaves.
New to the term? Read what CPA means in the glossary.
How to calculate CPA: a worked example
A store spends $3,000 on ads and gets 75 orders. The average order is $70 and the gross margin is 55%.
- CPA = $3,000 ÷ 75 = $40
- Break-even CPA = $70 × 55% = $38.50
- Each first order loses $40 − $38.50 = $1.50
The first order almost pays for itself. If customers come back, the campaign likely makes money; if they don't, it loses a little on every sale.
What is a good CPA?
A good CPA is below what an order leaves you in gross profit. If you can wait for repeat orders, the ceiling rises to the gross profit a customer brings over their lifetime.
Work out both numbers: first-order break-even (order value × margin) and lifetime break-even (from the LTV calculator). A CPA between the two pays back only if customers reorder.
Questions about CPA
- What's the difference between CPA and CAC?
- CPA counts ad spend per conversion, and a conversion can be any action, including repeat orders. CAC counts all sales and marketing spend per new customer. CAC is the stricter number for deciding whether growth pays.
- Why is my CPA higher in Shopify than in Meta?
- Meta counts orders it can link to an ad inside its attribution window, which Shopify may credit elsewhere. Dividing spend by fewer credited orders gives a higher CPA. Pick one source and compare it with itself over time.
- How do I lower CPA?
- Raise the share of clicks that buy. A page that matches the ad's offer, loads fast and answers objections lowers CPA without touching the ad budget, and it works for every campaign pointing there.
Do it with Replo
Get CPA by campaign every Monday
Replo pulls spend and orders, works out CPA for each campaign and emails you the report.
Prompt: “email me CPA by campaign every Monday”