Unit Economics
The revenue and cost associated with a single 'unit' of a business — typically one customer or one transaction. The fundamental test of whether a business model can ever be profitable.
Unit economics strips a business down to its single-customer (or single-transaction) profit math. If you can't make money on one customer, no amount of scale will fix it — you'll just lose more money faster.
The basic equation
For a subscription business:
Unit profit = LTV − CAC
Where:
- LTV = lifetime value of a customer (gross profit per customer over their entire relationship)
- CAC = customer acquisition cost (sales + marketing spend to acquire one customer)
A business with positive unit economics can, in principle, scale to profitability — every additional customer adds incremental profit. Negative unit economics is a hole that gets deeper with growth.
Why it matters
The dot-com era and the ZIRP era both produced businesses that grew rapidly with negative unit economics, fueled by venture capital subsidizing every transaction. When capital tightened, those businesses had to either find positive unit economics fast or shut down. Examples are still being filed.
Unit economics is the single most diagnostic question an investor or operator can ask about a startup's viability — more diagnostic than revenue growth, more diagnostic than user counts, more diagnostic than press coverage.
The trap
Unit economics is also abusable. The temptation is to define "unit" creatively to make the math look good — leaving out customer support cost, hosting cost, sales commission, etc. Honest unit economics includes all variable cost of serving that customer.
A 10-minute test: take your last quarter's P&L, divide variable cost by number of customers served, divide gross revenue by customers, compute. If the per-customer number is negative, the business model needs to change.