Enter your ad spend and the conversions it produced to get your cost per acquisition, and, with revenue per conversion, your profit per customer.
How it works
CPA (cost per acquisition) is what one conversion, a sale, lead, or signup, costs you in ad spend. It is the number that decides whether a campaign can scale: profitable when CPA sits comfortably below what a conversion is worth, unprofitable the moment it does not.
Formula: CPA = Ad spend / Conversions.
Advanced options add revenue per conversion, giving you profit per conversion, total revenue, and ROAS alongside the CPA.
Everything runs in your browser. Your numbers are never sent to a server, and there is no signup or limit. Your last entries are remembered locally so the calculator is ready next time.
Frequently asked questions
How do I calculate CPA?
Divide total ad spend by the conversions it generated. $1,000 of spend producing 50 sales is a $20 CPA. Count the conversions that matter to revenue (purchases, qualified leads), not clicks.
What is a good CPA?
One meaningfully below the value of a conversion. For one-off sales, keep CPA under your profit per order; for subscriptions, compare CPA to customer lifetime value (a common target is LTV of at least 3x CPA). There is no universal "good" number, only good relative to what a customer is worth to you.
What is the difference between CPA and CAC?
CPA usually measures a single campaign's cost per conversion from ad spend alone. CAC (customer acquisition cost) is the company-wide version: all sales and marketing costs divided by new customers. Our CAC Calculator handles that broader math.
How do I know if my CPA is profitable?
Turn on Advanced options and enter your revenue per conversion; the calculator shows profit per conversion (revenue minus CPA) and ROAS. If profit per conversion is negative, the campaign loses money on every sale before other costs.
Is this CPA calculator free?
Yes, free with no signup, running entirely in your browser.