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 costs you in ad spend. A conversion can be a sale, a lead, or a signup. It is the number that decides whether a campaign can scale. The campaign is profitable when CPA sits well below what a conversion is worth, and 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 produced. $1,000 of spend that produces 50 sales is a $20 CPA. Count the conversions that matter to revenue, such as purchases and qualified leads, not clicks.
What is a good CPA?
One well below the value of a conversion. For one-off sales, keep CPA under your profit per order. For subscriptions, compare CPA with customer lifetime value. A common target is a lifetime value of at least 3 times 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 one 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, which is revenue minus CPA, and ROAS. If profit per conversion is negative, the campaign loses money on every sale before other costs.
Why is my CPA higher than my CPC times clicks suggests?
Because not every click converts. CPA equals CPC divided by conversion rate. A $1 CPC at a 2 percent conversion rate is a $50 CPA. Raising the conversion rate lowers CPA just as much as lowering the click price does.
Should I measure CPA per campaign or per channel?
Both. Per campaign tells you which ads to scale or stop. Per channel tells you where to move budget. Run the calculator once for each, using the spend and conversions for that slice only.
What is a target CPA?
The most you can pay per conversion and still make money. Work backwards from profit per order or from lifetime value. Ad platforms let you set it as a bidding goal. Use this calculator to check your real CPA against it after the campaign runs.
Is this CPA calculator free?
Yes. It is free with no signup and runs entirely in your browser.