The 5 unit economics every founder must know

Growth feels good. But growth that loses money on every sale just helps you go bankrupt faster. Unit economics tell you which one you have — before the bank balance does.

Unit economics measure the profit (or loss) of a single customer or transaction. Get these five right and you can scale with confidence. Ignore them and you're flying blind.

1. Gross margin

Revenue minus the direct cost of delivering it, as a percentage. It's the ceiling on everything — sales, marketing, overhead all come out of gross profit. If your gross margin is thin, no amount of growth fixes it; it just magnifies the problem.

2. Contribution margin

Gross margin minus the variable costs of winning and serving that customer — payment fees, shipping, returns, support, ad spend tied to the sale. This is the number that reveals whether a product or channel actually makes money. Many "profitable" companies discover whole product lines are underwater here.

3. Customer Acquisition Cost (CAC)

Total sales and marketing spend divided by the number of new customers it produced. If it costs $1,000 to acquire a customer worth $400, you have a problem no spreadsheet optimism can hide.

4. Lifetime Value (LTV)

The total contribution margin you expect from a customer over their relationship with you. The healthy rule of thumb: LTV should be at least 3× CAC. Below that, you're buying revenue you can't profit from.

If LTV-to-CAC is below 3:1, more growth makes things worse, not better. Fix the unit before you pour fuel on it.

5. CAC payback period

How many months of margin it takes to earn back the cost of acquiring a customer. Under 12 months is generally healthy; the shorter it is, the less cash you tie up funding growth. This single metric often decides how fast you can responsibly scale.

Where founders go wrong

The most common error is computing these at the blended company level and missing that some segments are great and others are terrible. Break every metric down by product, channel and customer type. That's where the real decisions hide — what to double down on, what to fix, and what to cut.