CPA Calculator
Calculate cost per acquisition (CPA) from ad spend and conversions — what each sale, signup or lead costs you.
How it works
CPA = ad spend ÷ conversions
Cost per acquisition — also called cost per action — is what you pay, on average, for each conversion a campaign produces, whether that conversion is a sale, a signup or a qualified lead. Divide total spend by the number of conversions. Unlike cost per click, CPA counts only the visits that actually did what you wanted, so it is a truer measure of what your marketing costs. CPA only tells you if a campaign is profitable when you compare it to the value of a conversion: if each customer is worth more than the CPA, the campaign pays; if not, it loses money no matter how cheap the clicks were.
Worked example
A campaign that spent $1,000 and drove 25 conversions has a CPA of 1,000 ÷ 25 = $40. Each acquisition cost $40 — profitable only if a converted customer is worth comfortably more than that.
Frequently asked questions
What is the difference between CPA and CPC?
CPC is the cost of a single click; CPA is the cost of a completed conversion, such as a purchase or signup. Because only some clicks convert, CPA is always higher than CPC. CPA is the better measure of marketing efficiency because it counts results, not just visits.
What is a good CPA?
There is no universal figure — a good CPA is one comfortably below the value of a conversion. If a customer is worth $150 and your CPA is $40, the campaign is healthy; if the CPA is $200, it loses money. Compare CPA to customer lifetime value or average order value, not to a benchmark.
How do I lower CPA?
Raise conversion rate (better landing pages, clearer offers, fewer form fields), tighten targeting so spend reaches people more likely to convert, and cut keywords, placements or audiences that spend without converting. Improving the post-click experience often lowers CPA more than chasing cheaper clicks.
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Educational estimate, not financial advice.