CPA (Cost Per Acquisition) Calculator

Divide ad spend by conversions to see what each sale or lead really costs — and whether you're beating your target CPA.

Ad spend ($)

Conversions (sales, leads, sign-ups)

Target CPA ($) — editable default

What cost per acquisition tells you

Cost per acquisition (CPA) is the bluntest, most useful number in paid marketing: total ad spend divided by the conversions that spend produced. Spend $1,000 and get 40 sales, and each sale cost $25 to win. A "conversion" is whatever action you pay for — a purchase, a qualified lead, an app install, an email sign-up. Everything runs in your browser; your budgets and results never leave your device.

Working backwards from a target CPA

CPA alone doesn't say whether a campaign is healthy — that depends on what an acquisition is worth to you. Set a target CPA (many sellers use profit per order, or a slice of customer lifetime value) and the calculator compares your actual CPA against it, then flips the math both ways: the conversions your current spend must generate to hit the target, and the maximum you can spend at your current conversion count before blowing past it. All defaults here are approximate and editable — platform costs and benchmarks change constantly, so check your platform's current fees and figures; results are estimates only, not financial advice.

How to use it

Enter your total ad spend for the period (include management fees for a true all-in CPA).
Enter the conversions that spend generated in the same period.
Set a target CPA to compare against — break-even profit per sale is a good start.
Read the cards: your actual CPA, how far over or under target you are, conversions needed to hit target, and the max spend that stays under it.

FAQ

What counts as a conversion?: Whatever action you're optimizing for: purchases, leads, sign-ups, installs. Just be consistent — don't mix leads and sales in one calculation, because they have very different values.
Is CPA the same as CAC?: Close cousins. CPA measures the cost of a single conversion from ad spend alone, while CAC divides all sales & marketing costs by new customers. A repeat buyer can create a conversion without being a new customer.
What is a good CPA?: Anything comfortably below your profit per acquisition. If a sale nets $30 of margin, a $25 CPA leaves almost nothing; many e-commerce sellers aim for a third or less of order profit.
Why does my CPA differ from my ad platform's?: Platforms count conversions inside their own attribution window and may include view-through conversions. Your own verified sales numbers usually give a more conservative, more honest CPA.