CAC: customer acquisition cost
CAC (Customer Acquisition Cost) is the advertising cost per acquired customer: advertising spend divided by the number of new customers in the period.
Formula
CAC = advertising spend ÷ new customers
The numerator is acquisition spend; the denominator is new customers, not inquiries or orders. The periods must match. This example includes advertising only. Fully loaded acquisition cost can also include salaries, tools and contractors; in that case use all acquisition costs, not just the ad budget.
- Spend — advertising budget for the period (₽)
- Customers — new customers in the same period (items)
Worked example
- Advertising budget: 120 000 ₽
- New customers: 40
- CAC = 120,000 ₽ ÷ 40 customers
Result: 3,000 ₽ per customer.
How to interpret it
- CAC is not inherently “good” or “bad”; compare it with contribution profit per customer over the same horizon.
- When CAC is below first-order contribution, advertising pays back immediately. Longer horizons include repeat purchases.
Common mistakes
- Dividing spend by leads or orders instead of customers gives CPL or CPO, not CAC.
- Comparing monthly CAC with annual contribution profit mixes horizons.
- Including repeat purchases in the denominator when measuring the cost of initial acquisition.
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Editorial team: MARKMA Editorial Team. Reviewed: .