Advertising
CAC Calculator
Paid and blended customer acquisition cost, and the gap between them.
Paid CAC and blended CAC answer different questions
Paid CAC is marketing cost divided by the customers that marketing actually produced. It tells you whether to spend the next dollar, and it is the number a media buyer should be working to.
Blended CAC divides the same cost across every customer, including the ones who arrived on their own. It tells you what the business as a whole is paying to grow, and it is the number an investor will ask for.
The gap between them is the thing to watch
A wide gap means organic is carrying the numbers. That is good news about the business and dangerous news about the paid channel, because blended CAC will look healthy while paid is losing money on every customer — and scaling spend makes the blended figure worse, not better, since new spend brings no new organic with it.
If someone quotes you a CAC without saying which one it is, it is almost always blended.
What to include
Ad spend, agency and freelancer fees, marketing salaries, and the tools that exist to run marketing. Not product, not support, not the founder's time unless you are counting it consistently everywhere else. What matters more than the exact boundary is that it does not move between months.