Customer Acquisition Cost (CAC) Calculator

Find out what each new customer really costs you — and how fast they pay you back.

📖 How it works & FAQ

Marketing spend ($)

Sales spend ($)

New customers acquired

Monthly revenue per customer ($)

Gross margin (%)

What customer acquisition cost actually measures

Customer acquisition cost (CAC) is the simplest health check in marketing: take everything you spent on sales & marketing over a period — ads, agency fees, sales salaries, tools, commissions — and divide it by the number of new customers you won in that same period. If you spent $8,000 and gained 120 customers, each one cost you about $66.67. Everything runs in your browser; nothing you type is uploaded anywhere.

Payback: the number CAC is useless without

A $67 CAC is great for a subscription business and terrible for a $10 one-time product. That's why this calculator also shows payback time. Each month, a customer contributes revenue × gross margin in actual profit dollars. Divide CAC by that monthly contribution and you get the number of months before a customer has paid for their own acquisition. Most healthy subscription and repeat-purchase businesses aim to recover CAC within 12 months; the 12-month return card shows how many times over a customer repays their cost in the first year.

How to use it

Enter your marketing spend and sales spend for the period (a month or a quarter both work — just be consistent).
Enter how many brand-new customers you acquired in that same period.
Add the average monthly revenue one customer generates, and your gross margin percentage.
Read the results instantly: CAC, monthly margin per customer, months to recover CAC, and the 12-month return multiple.

These figures are simplified estimates for planning only — not financial, tax, insurance, or legal advice.

FAQ

What costs should I include in sales & marketing spend?: Everything spent to win new customers: ad spend, content and agency costs, marketing software, plus salaries and commissions for sales and marketing staff. Leaving salaries out is the most common way founders understate CAC.
Should I count returning customers?: No — CAC only divides by first-time customers. Repeat orders are a retention win, not an acquisition win, and mixing them in makes CAC look artificially low.
What is a good CAC payback period?: Under 12 months is the common benchmark for subscription businesses; cash-tight startups often push for 6. One-time-purchase businesses need to recover CAC on the very first order.
Why use gross margin instead of revenue for payback?: Revenue includes the cost of delivering the product. Only margin dollars are available to repay acquisition spend, so payback based on revenue would look misleadingly fast.