Formula
CAC = Total Sales & Marketing Spend ÷ New Customers
FAQ
What CAC is acceptable?
Only relative to LTV — a 3:1 LTV:CAC ratio is the common health threshold, so CAC should generally be around a third of customer lifetime value or less.
Should I use a blended or paid-only CAC?
Both. Blended shows the whole machine; paid-only shows channel efficiency. Divergence between them tells you how much organic is subsidizing paid.