CAC (Customer Acquisition Cost)

CAC (Customer Acquisition Cost) is the total cost of winning one new customer. You add up everything you spent acquiring customers in a period, sales, marketing, ad budget, tooling, and the salaries behind them, then divide by the number of new customers that spend produced.

How to calculate CAC

If you spent $40,000 on sales and marketing in a quarter and gained 200 customers, CAC is $200. The number is only honest if the numerator is fully loaded. Include salaries, commissions, agency and contractor fees, software, and creative production, not just paid ad spend. Leaving out headcount is the most common way teams quietly understate CAC.

Two refinements worth making:

• Blended vs paid CAC — blended CAC divides by all new customers including organic and word-of-mouth. Paid CAC counts only customers from paid channels and is the truer read on channel efficiency.
• Attribution lag — spend in one month can produce customers months later. For long sales cycles, match spend to the cohort it actually acquired rather than the calendar month.

Why CAC matters

CAC alone means nothing, its value is always relative. Compared against LTV it produces the LTV:CAC ratio, the standard test of whether acquisition pays off. Divided into monthly revenue it gives the CAC payback period, which tells you how long a customer takes to cover their own acquisition cost. A CAC that rises faster than ARPA is an early warning that a channel is saturating or that you're chasing lower-quality customers.