Free Burn & Runway Calculator

How this tool computes its result

Reports two different runway numbers from the same inputs. "Current runway" is a single division: cash on hand ÷ (monthly expenses − monthly revenue), only computed when that net burn is positive (otherwise it reports "profitable/break-even"). "Projected runway" instead runs a month-by-month simulation for up to 240 iterations: each month it subtracts that month's net burn from cash, then grows revenue and expenses by the entered monthly growth percentages before moving to the next month, stopping as soon as cash drops to zero or below.

Worked example

With cash on hand $500,000, monthly revenue $120,000, monthly expenses $180,000, and both growth rates left at 0% (the field defaults), current net burn is $60,000/month, so current runway = 500,000 / 60,000 = 8.33 months. The month-by-month simulation, however, subtracts $60,000 every month: after month 8, cash sits at $500,000 − 8×60,000 = $20,000 (still positive), and only after month 9 does cash go to −$40,000. The tool therefore reports a projected depletion of 9 months even at 0% growth — one month later than the continuous-division "current runway" figure, because the simulation only checks depletion at whole-month boundaries.

When not to use this tool

The growth-rate model assumes smooth, constant compounding every month with no seasonality, one-time costs, or funding events, and the simulation is hard-capped at 240 months — beyond that it reports "no depletion within 240 months," which describes the simulation's limit, not a guarantee of indefinite runway.

Common mistakes

• - Entering annual revenue or expense figures instead of monthly ones — there's no unit check beyond requiring cash and expenses to be greater than zero, so an annual figure entered by mistake produces a wildly wrong burn rate.
• - Reading "current runway" and "projected runway" as the same metric — they use different math (continuous division vs. discrete monthly simulation) and can disagree even at 0% growth, as shown above, purely because of how the simulation rounds at month boundaries.
• - Leaving monthly revenue blank while expecting the burn figure to reflect real income — a blank revenue field defaults to 0, so net burn is computed as the full expense figure with no revenue offsetting it.

Related tools