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CAC & Payback Period Calculator
See what a new customer really costs and how long it takes to earn that money back — the two numbers every subscription business should know cold.
Calculations run locally in your browser.
Why CAC and payback matter
Customer Acquisition Cost (CAC) is your total sales and marketing spend divided by the customers you gained. A low CAC is only half the story — payback period tells you how many months of gross margin it takes to recover that spend. Faster payback means less cash locked up funding growth.
How it's calculated
- CAC = Marketing Spend ÷ New Customers
- Gross-Margin CAC = Spend ÷ (Customers × Gross Margin)
- Monthly Contribution = ARPU × Gross Margin
- Payback = Gross-Margin CAC ÷ Monthly Contribution