Runway

Runway is how long a business can keep operating before it runs out of money, based on how much cash it holds and how fast it is spending. If you know the cash in the bank and the amount going out each month, the runway is roughly the first divided by the second.

It is like watching the fuel gauge on a long drive and knowing how far you can go before the next station. Runway matters because it is the single number that tells founders how much time they have to reach profit or raise more money, and misjudging it is a common way businesses run into trouble.