Customer Acquisition Cost is the total marketing spend over a period divided by the number of customers acquired in that period. Unlike CPA, which only counts the paid-media line item, CAC includes everything in the acquisition funnel — content production, agency fees, software, attributable salary.
CAC = (Paid Marketing Spend + Marketing Salaries + Tools + Content Costs) / New Customers Acquired
Why it matters
CAC is the number a CFO actually cares about. It tells you the real economic cost of growth, not just the bid your media buyer is paying. Healthy unit economics depend on LTV being a defensible multiple of CAC — usually 3× or better.
Blended vs paid CAC
Blended CAC divides total spend by total new customers — including organic, referrals, and word-of-mouth. Paid CAC isolates just the customers who came through paid channels. Watch both: blended CAC tells you the macro health of growth; paid CAC tells you whether your acquisition machine specifically is working.