Cost Per Acquisition Calculator

Quick answer

Cost per acquisition (CPA) = marketing and sales spend ÷ new customers or conversions. $5,000 spent for 80 customers is $62.50 each.

Enter the spend and the number of acquisitions. The calculator returns the cost of each.

Related tools: Cost Per Click Calculator: Average cost of each ad click. YouTube Earnings Calculator: Estimated ad earnings from views and RPM. Average Order Value Calculator: Revenue per order.

How to use the Cost Per Acquisition Calculator

1. Enter marketing and sales spend ($) (0 or more).
2. Enter new customers or conversions (above 0).
3. Press Calculate to see the result, and use Reset to start again.

Formula and method

Include all costs you want attributed to acquisition.

Worked examples

These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.

The first line is the headline result (cost per acquisition). IEEE-754 double precision; shown to the decimals indicated.

Judging the number

CPA only means something next to what a customer is worth. If the average customer brings $150 of gross profit, a $62.50 CPA is healthy; if they bring $40, it is not. Compare with customer lifetime value.

Be consistent

Include all spend you attribute to acquisition (ads, tools, agency fees, sales time) for the same period as the conversions. Delays between spending and conversion can make a single month's figure misleading.

How the result changes with marketing and sales spend

Holding every other input at the first worked example, this table changes only marketing and sales spend. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.

What happens with invalid input

These messages are produced by the calculator itself, so you know what to fix.

• New customers or conversions: entering "0" shows "New customers or conversions must be greater than 0." beside that field and no result.
• Marketing and sales spend: left empty shows "Enter marketing and sales spend." beside that field and no result.

Choosing between the Cost Per Acquisition Calculator and similar calculators

Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.

Background: business metrics

Business ratios depend on exactly which costs and revenues you include, so read each page's definition. Two common checks: break-even units = fixed costs ÷ (price − variable cost per unit), so $50,000 of fixed costs with a $10 price and $5 variable cost breaks even at 10,000 units; and net profit margin = net profit ÷ revenue, so $20,000 profit on $100,000 revenue is 20%.

Return on investment ignores time: 20% over five years is far less impressive than 20% in one, so compare returns over the same period.

Assumptions and limitations

• Conversions must be positive

If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for new customers or conversions and marketing and sales spend to confirm this.

Related calculators

• Cost Per Click Calculator — Average cost of each ad click.
• YouTube Earnings Calculator — Estimated ad earnings from views and RPM.
• Average Order Value Calculator — Revenue per order.
• Conversion Rate Calculator — Share of visitors who convert.
• Customer Lifetime Value Calculator — Customer lifetime value from revenue, margin and churn.
• Cost of Goods Sold Calculator — COGS from inventory and purchases.

Sources

• OpenStax, Principles of Accounting, Volume 2: Managerial Accounting (Rice University)

Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.