Unit economics on a napkin

Growth hides bad math. Founders chase more customers to fix a business that loses money on every one — and the losses just get bigger, faster.

Before you scale anything, check a single sale on a napkin. Three numbers:

• Margin: what’s left from one sale after the direct cost of delivering it.
• CAC: what it costs to get one customer.
• LTV: what that customer is worth over their whole life with you.

The rule of thumb: LTV should comfortably beat CAC, and the margin should pay back the CAC in months, not years. If it doesn’t work for one customer, more customers won’t save you.

It’s a five-minute check that prevents a two-year mistake. Do it before the ad spend, not after.