How the calculator works
Every month revenue is added to the cash in the bank and costs are taken away. If revenue grows, the calculator increases it by the given percentage each month. Runway is how many months pass before the money runs out.
runway = cash in the bank ÷ (monthly costs − monthly revenue)
Without revenue growth it's simple division. With growth it's hard to do in your head: burn shrinks every month, and the company may turn profitable before the money runs out. Then the calculator shows how many months that takes and the lowest your cash gets.
When to start raising
The calculator sets the date nine months before zero. Talks with funds usually take three to six months, plus time to prepare, plus a cushion in case the first round falls through. With less than nine months of money, start now: with a short runway it's no longer you setting the terms.
Why real runway is usually shorter
- Costs grow. New people, taxes, raises — in six months a month costs more than it does now.
- Revenue grows slower than planned. If you're not sure about growth, run it with zero too — that's the honest lower bound.
- One-off payments. Annual software plans, equipment, lawyers.
More on calculating runway and what to do about it in Startup runway. What burn, rounds and valuation mean — in the glossary.
Test it on your own decisions
The calculator shows what happens if nothing changes. In Runway 200 runway changes every week with your decisions: a new hire raises the burn, a price increase raises revenue and churn. The first ten weeks are free, no sign-up.