“What's your CAC, and how do you calculate it?”

What they're really asking

Do you include everything? Investors rarely care about the question on its own. They're testing whether you know your numbers cold, whether your assumptions are honest, and whether you can explain them simply.

How to answer, step by step

1. Use all sales and marketing cost, including salaries.
2. Divide by all new customers in the same period.
3. Give paid-only CAC separately.

An example answer

Blended CAC over the last 12 months is about $1,765: $60k of S&M spend for 34 new customers.

Figures are from Loopdesk, the fictional SaaS company in our sample files. Swap in your own numbers and keep the structure.

The answer that loses trust

Where the proof lives

Before the meeting, find the number behind your answer. In our workbooks it lives in: LTV & Payback, CAC by Channel. If you can open that tab and point to it, the follow-up question is easy.