Startup Runway Calculator

Runway is the number of months a company can keep operating before its cash balance reaches zero. The simple form divides cash by net burn, where net burn is monthly expenses minus monthly revenue. Gross burn ignores revenue entirely and measures total outflow, so the two diverge sharply once a company has meaningful sales: a business spending 200,000 dollars and earning 80,000 dollars a month has a gross burn of 200,000 and a net burn of 120,000. The dynamic projection here compounds revenue and expenses at separate monthly rates, which changes the answer materially. If revenue compounds at 8 percent and expenses at only 3 percent, net burn shrinks every month and true runway is longer than the static division suggests, becoming effectively unbounded once the two curves cross. Common thresholds are 12 to 18 months as a working minimum, 18 to 24 months as comfortable, and under 6 months as critical, since a financing round typically takes 3 to 6 months from first meeting to wired funds. A companion metric is the burn multiple, net burn divided by net new annual recurring revenue, where a value under 1 is exceptional and above 3 signals inefficiency. The main caveats are that a cash balance is not the same as working capital, annual prepayments make monthly cash lumpy rather than smooth, and headcount costs move in discrete steps rather than by a smooth percentage.

Cash forecasting is as old as double-entry bookkeeping, but the specific term burn rate entered common business usage during the dot-com boom of the late 1990s, when investors and financial journalists needed shorthand for how fast unprofitable internet companies were consuming venture capital. After the 2000 crash, when a large share of those companies failed with cash exhaustion rather than any single operational failure as the proximate cause, runway became a standing board-meeting agenda item rather than an occasional calculation. Paul Graham formalized the underlying question in his 2015 essay distinguishing companies that are default alive, meaning on track to reach profitability on existing cash at current growth, from those that are default dead and therefore dependent on a future round. In 2020, David Sacks of Craft Ventures introduced the burn multiple to measure how much cash a company consumes per dollar of new recurring revenue, shifting attention from runway length to burn efficiency. The funding contraction of 2022 and 2023 pushed conventional guidance up sharply, with many investors advising portfolio companies to cut costs far enough to reach 24 to 30 months of runway. Post-mortem research by CB Insights has repeatedly found running out of cash and failing to raise new capital among the leading stated causes of startup failure.