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 total campaign cost divided by the number of conversions.
  • CPA is most precise when the conversion is an acquisition.
  • A good cost per conversion depends on margin, order value and customer quality.

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Calculate cost per conversion

Enter campaign spend and conversions to calculate cost per conversion, CPA, conversion rate and ROAS.

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The cost per conversion formula

Cost per conversion = total campaign cost divided by number of conversions. If a campaign spends GBP 750 and records 50 conversions, GBP 750 divided by 50 gives a cost per conversion of GBP 15. Use campaign cost and conversions from the same reporting period.

Cost per conversion and CPA

CPA means cost per acquisition. Many marketing teams use CPA and cost per conversion interchangeably, but CPA is most precise when the conversion is a new customer, lead, signup or other acquisition. If the conversion is an earlier action such as a checkout start, cost per conversion is the clearer label.

Marketing cost per conversion vs accounting conversion costs

This guide covers marketing and advertising cost per conversion. Searches for conversion costs can also refer to a different accounting concept used in manufacturing. That is not the metric calculated here: marketing cost per conversion compares campaign cost with completed conversions.

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 useful 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 when the value generated by each customer is strong.

Related calculators

Try the numbers yourself

Open the calculators that match this topic and test the result with your own inputs.

Cost Per ConversionCalculate cost per conversion, CPA, conversion rate, revenue per conversion and ROAS from campaign spend and conversions.CPCCalculate CPC, cost per click, CPM, CTR, cost per conversion and ROAS from paid campaign data.Conversion RateCalculate website, ecommerce, sales, retail or marketing conversion rate, plus target uplift and value per visitor.ROASCalculate return on ad spend, gross profit after margin and break-even ROAS.Profit MarginCalculate gross profit, profit margin and markup from cost and selling price.