Runway calculator

Default alive is a term from Paul Graham: if you keep spending and growing at your current rate, does revenue overtake costs before the cash runs out? If yes, you're default alive and control your own fate. If no, you're default dead, quietly relying on raising more money or a change you haven't planned yet.

A single number like "eight months" flattens a moving picture into one point. If you're growing, revenue covers more of your costs each month, so your real runway is longer than a flat calculation suggests. A smooth average also hides lumpy costs, like a tax bill or a big hire, that can eat months of runway in one hit.

Burn rate is how much cash you lose each month: money out minus money in. Runway is how long your cash lasts at that rate: cash divided by monthly burn. The zero-cash date is that runway placed on a calendar, the month you'd hit empty if nothing changes.

There are three levers, and you can test each one here. Cut spending: since burn is the denominator, trimming it moves runway more than almost anything else. Grow revenue faster, or add cash through a raise or loan, which lifts your starting balance and pushes the zero-cash date out.