Quick brief
What to know before you calculate
A short read on the assumptions, trade-offs and definitions that shape the answer.
- Cost per conversion equals campaign cost divided by conversions.
- CPA is most precise when the conversion is an acquisition.
- A good cost per conversion depends on margin, order value and customer quality.
The cost per conversion formula
Cost per conversion is calculated by dividing total campaign cost by conversions. If a campaign spends GBP 750 and records 50 conversions, cost per conversion is GBP 15. The formula is simple, but the usefulness depends on clean cost and conversion definitions.
Cost per conversion and CPA
CPA means cost per acquisition. Many teams use CPA and cost per conversion interchangeably, but CPA is most accurate when the conversion is a new customer, lead, signup or acquisition. If the conversion is a checkout start or page view, cost per conversion is the clearer label.
Choose the right conversion count
Use conversions from the same attribution window and reporting period as the campaign cost. If one channel reports seven-day click conversions and another reports same-session purchases, the resulting cost per conversion will not be directly comparable.
Compare against break-even value
A cost per conversion is only good if it fits the economics of the business. Compare it with revenue per conversion, gross margin, fulfilment cost, refunds and likely repeat value. A higher CPA can still work if the customer value is strong.
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