- Most founders quote a runway number that assumes best-case collections and no surprises.
- Real runway is cash divided by honest burn, including the payments that are merely delayed, not avoided.
- Decisions made with three months of clarity beat the same decisions made with three weeks of panic.
Ask a founder their runway and the answer comes fast: "about nine months." Ask what is behind the number and it gets quieter. The nine months assumes every invoice pays on time, the annual insurance bill is somehow not coming, the two contractors are not really burn, and next quarter's revenue lands as forecast. The real number is six. The founder will discover this in month five.
How the comfortable number gets built
Nobody fabricates a runway figure. It assembles itself from small optimisms: revenue counted before it is collected, lumpy annual costs smoothed into invisibility, hiring plans excluded because they are "not approved yet," and a burn figure from the one recent month that happened to be cheap. Each choice is defensible. Together they add two to four months of fiction to the number the founder repeats.
What the honest version looks like
- Start from bank cash only. Committed investment that has not cleared is a promise, not runway.
- Use trailing average burn, including the lumpy months. Insurance, tax deadlines, and annual contracts are burn, whichever month they strike.
- Count revenue when it collects, not when it books. A signed contract with sixty-day terms is zero cash for two months.
- Run the pessimistic case as the headline. If collections slip and one deal pushes, that number is the one decisions should rest on.
Why the honest number is worth the discomfort
Runway is not a vanity metric; it is a decision clock. Cutting costs, raising money, or changing strategy all take a quarter to execute well. A founder who believes in nine months when the truth is six makes those calls with the clock already expired, choosing between bad options at speed. The one who knows it is six moves while there are still choices. The mechanics of getting paid faster, covered in our piece on why cash flow kills more businesses than bad products, can buy weeks. Honesty about the number buys months.
Frequently asked questions
How is real runway calculated?
Cash actually in the bank, divided by trailing average monthly burn including lumpy
annual costs, counting only revenue that has historically collected on time.
How often should a founder recalculate runway?
Monthly at minimum, weekly when under twelve months. The number moves with every
hire, every delayed invoice, and every annual bill.