Startup Runway & Burn Rate Calculator

Your gross burn is your total monthly expenses. Your net burn is expenses minus the gross-margin contribution from revenue — the cash you actually consume each month. The simplest runway estimate is cash divided by net burn, but that only holds if nothing changes.

In reality, several things move at once, so this calculator projects month by month instead: revenue compounds at your expected growth rate, expenses grow too (hiring rarely stays flat), and only your gross margin on revenue offsets burn — selling a dollar at 70% margin only buys you 70 cents of runway. We track the cash balance until it reaches zero, or until contribution overtakes expenses and you never run out.

Four inputs change the answer the most: revenue growth, expense growth, gross margin, and your starting cash. A team that holds expenses flat while revenue compounds can extend runway dramatically; a team that scales hiring ahead of revenue can burn through a raise far faster than a simple cash ÷ burn estimate suggests.

That's why we surface both gross and net burn, the out-of-cash date, and a "start raising by" date — the planning horizon that actually matters, set a buffer before zero so a raise has time to close.

Paul Graham's framing is the one that matters: are you "default alive" (on current trajectory, you reach profitability before the money runs out) or "default dead" (you don't)? If your modelled revenue growth lets the balance stop falling before zero, the calculator flags you as default alive.

Knowing which side of that line you're on changes everything — from how hard you fundraise to whether you cut costs this month.

A common rule of thumb is to start raising with 6–12 months of runway left, because raising takes longer than founders expect. Watch your out-of-cash date, and treat the months between now and the start of a raise as the real planning horizon — not the date the cash actually hits zero.