CostCPA Calculator
Calculate cost per acquisition from advertising spend and number of acquired customers or conversions.
Enter your values and press Calculate.
Tip: country presets are starting points only. Replace rates and prices with your actual figures whenever possible.
How this calculator works
Cost per acquisition equals campaign spend divided by the number of acquisitions. The optional order value input provides a simple revenue comparison.
Formula
$3,000 of advertising that generates 120 customers produces a $25 CPA.
Getting a more accurate result
- Define acquisition consistently: customer, sale, lead or signup.
- Use the same attribution window for spend and conversions.
- Compare CPA with contribution margin or customer lifetime value, not just revenue.
Understanding your result
The result is intended for comparison and planning. Real-world costs can differ because of local taxes, fees, tariffs, financing, usage patterns, equipment efficiency, rounding and other conditions. For important decisions, verify the inputs against your bill, contract, lender, employer or other authoritative source.
Frequently asked questions
What is a good CPA?
It depends on your margins, repeat purchase rate and customer lifetime value.
Can CPA be used for leads?
Yes, but it is often called cost per lead when the conversion is a lead rather than a customer.
Why can platform CPA differ from accounting CPA?
Different attribution rules and conversion windows can produce different counts.
Connect CPA to conversion rate and margin
CPA divides advertising spend by the number of acquired customers or conversions. Define the conversion consistently: a lead, trial and completed purchase are different outcomes. A campaign can have a low CPA and still lose money if gross profit per customer is lower than acquisition cost.
A campaign spending $3,000 and producing 120 first-time customers has a $25 CPA. If average contribution profit before advertising is $38 per new customer, the campaign contributes about $13 per acquisition before overhead and repeat purchases.
Before comparing campaigns
- Use the same attribution window and conversion definition.
- Remove refunds, test orders and duplicate leads where possible.
- Compare CPA with contribution margin, not revenue alone.
- Review lead quality and repeat purchase behavior alongside the headline CPA.
Related calculators and guides
Reviewed for CostMeter V1.5 • September 2026