What is CAC?
Customer acquisition cost
CAC is the total cost of winning one customer — all sales and marketing costs divided by new customers.
Formula
CAC = (Marketing + Sales costs) ÷ New customers
The difference from cost per lead is what's included. CPL usually counts ad spend and enquiries. CAC counts paying customers and everything spent to win them — ads, salaries, tools, agency fees, commissions. It's always the larger and more honest number.
CAC only means something next to lifetime value. The standard health benchmark is 3:1 — if a customer is worth $900, spending up to $300 to acquire them is sustainable. Below 1:1 you're paying for the privilege of having customers.
A ratio far above 3:1 isn't automatically good news either. It often means you're under-spending and leaving growth to competitors who are willing to pay closer to what a customer is actually worth.