Customer Acquisition Cost (CAC)

The total cost of acquiring a new customer, including marketing spend, sales salaries, and any promotional incentives, divided by the number of customers acquired in a period. CAC is a crucial counterpart to Customer Lifetime Value (CLV); a sustainable subscription business requires CLV to exceed CAC by a healthy multiple. Upsells and retention strategies improve this ratio by extracting more value from existing customers, reducing the pressure to acquire new ones at ever-higher cost. A well-designed upsell architecture increases CLV without increasing CAC, making the entire business more efficient.

Example: A company that raises its average CLV from $400 to $520 through better trial-to-paid conversion can afford a higher CAC while maintaining the same unit economics.