CPA Calculator
Find your cost per acquisition by dividing ad spend by conversions, with cost per click, conversion rate and ROAS when you add clicks and revenue. Or switch modes to work out the break-even and target CPA your margin can afford.
Sales, sign-ups or leads, whatever you count as an acquisition.
Adds cost per click and conversion rate.
Adds ROAS and return per conversion.
Average order value or value of a lead/customer.
Gross margin after product, shipping and fees, before advertising.
Share of revenue you want to keep as profit.
Adds the maximum cost per click you can bid.
How to use the CPA Calculator
- Choose a mode: CPA from ad spend, or target CPA from your margin.
- For actual CPA, enter ad spend and conversions, and optionally clicks and revenue per conversion.
- For target CPA, enter revenue per conversion, your margin before ads and the profit you want to keep.
- Read the result and use the table to compare scenarios.
- Copy the results or download the table for your campaign report.
CPA formulas
- CPA = ad spend ÷ conversions = CPC ÷ conversion rate
- Break-even CPA = revenue per conversion × margin before ads
- Target CPA = revenue per conversion × (margin before ads − desired profit %)
- Maximum CPC = target CPA × conversion rate
- ROAS = revenue per conversion ÷ CPA
Example: $2,500 spent, 2,000 clicks and 100 sales gives CPC $1.25, a 5% conversion rate and a CPA of $25. If each sale is worth $60, ROAS is 2.4×.
Break-even CPA by order value and margin
| Revenue per conversion | 20% margin | 30% margin | 40% margin | 50% margin | 70% margin |
|---|---|---|---|---|---|
| $25 | $5.00 | $7.50 | $10.00 | $12.50 | $17.50 |
| $50 | $10.00 | $15.00 | $20.00 | $25.00 | $35.00 |
| $80 | $16.00 | $24.00 | $32.00 | $40.00 | $56.00 |
| $100 | $20.00 | $30.00 | $40.00 | $50.00 | $70.00 |
| $250 | $50.00 | $75.00 | $100.00 | $125.00 | $175.00 |
| $500 | $100.00 | $150.00 | $200.00 | $250.00 | $350.00 |
Your target CPA should sit below these break-even values to leave room for profit. If customers buy again, you can justify a higher first-order CPA based on lifetime value.
Frequently asked questions
How do you calculate CPA?
CPA = total ad spend ÷ number of conversions. If a campaign cost $2,500 and produced 100 sales, the cost per acquisition is $25. CPA also equals cost per click ÷ conversion rate.
What is a break-even CPA?
Break-even CPA is the most you can pay for one conversion without losing money: revenue per conversion × profit margin before advertising. An $80 order with a 40% margin has a break-even CPA of $32.
How do I set a target CPA?
Subtract the profit you want to keep from your margin before ads, then multiply by revenue per conversion: target CPA = revenue × (margin − desired profit %). With $80 revenue, 40% margin and a 10% profit goal, the target CPA is $24.
What is the difference between CPA and CAC?
CPA usually measures the ad cost of a single conversion in a campaign, which may be a lead or a sale. Customer acquisition cost (CAC) is broader: it includes all marketing and sales costs, such as salaries and tools, divided by new paying customers.
What is a good CPA?
There is no universal number; a good CPA is one below your break-even CPA with room for profit. Compare it with what a conversion is worth to you, ideally including repeat purchases over the customer's lifetime.
How are CPA and ROAS related?
ROAS = revenue per conversion ÷ CPA. A $60 order bought at a $25 CPA gives a ROAS of 2.4×. Lowering CPA or raising order value both increase ROAS.
Is anything uploaded?
No. The calculator runs entirely in your browser.