Compute months of runway remaining, the zero-cash date, and how revenue growth extends your timeline.
Runway with current trajectory
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Gross burn (monthly expenses)
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Net burn (expenses - revenue)
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Runway at flat revenue
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Break-even month (with growth)
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Runway is a question about cash, not profit
Founders fixate on the wrong number when they ask how long they can last. Net income on an accrual P and L includes things that do not touch the bank account this month, like depreciation, and excludes things that very much do, like a quarterly insurance prepayment. Runway is simpler and crueler: how many months until the checking balance hits zero at the rate you are actually draining it. This tool answers that by separating gross burn from net burn and then layering in revenue growth, which is the variable that quietly decides whether you ever need to raise again.
Gross burn is every dollar of monthly expense. Net burn subtracts the revenue you collect, because revenue refills the tank while expenses empty it. A company spending $60,000 a month that books $25,000 in revenue is not burning $60,000. It is burning $35,000. Confusing the two is the single most common reason teams panic early or, worse, relax too late.
Walking through $500,000 in the bank
Take the default inputs: $500,000 of cash, $60,000 of monthly expenses, $25,000 of monthly revenue, and revenue growing 10 percent each month. Net burn today is $60,000 less $25,000, which is $35,000. If revenue never grew, you would divide $500,000 by $35,000 and get a flat runway of about 14 months. That is your worst case, the floor you should always know.
Growth changes the story. Each month revenue compounds by 10 percent, so net burn shrinks. By month 11 revenue has climbed past $60,000 a month and net burn turns negative, meaning the business funds itself. You cross break-even before the cash runs out, so runway with growth is effectively unlimited. The lesson is that a flat-revenue runway can look frightening while a modest, durable growth rate quietly rescues the whole plan.
| Figure | Value |
|---|---|
| Gross burn (monthly expenses) | $60,000 |
| Net burn, $60,000 less $25,000 | $35,000 |
| Flat runway, $500,000 divided by $35,000 | About 14 months |
| Revenue growth assumption | 10 percent per month |
| Break-even reached | Month 11, before zero cash |
Flat versus growing, side by side
The chart traces the cash balance two ways. The gray line holds revenue flat and marches straight to zero around month 14. The teal line lets revenue compound at 10 percent, dipping at first while burn still exceeds revenue, then flattening as break-even arrives near month 11.
Reading the result before a raise
This tool is for founders and operators planning a fundraise or a budget cut, and for anyone who needs a defensible answer when an investor asks how long the money lasts. The practical rule that experienced founders live by: start raising with at least 18 months of runway in hand, because a round typically takes 12 months to find and close and you want 6 months of buffer if it slips. Walking into a raise with under 12 months left hands every ounce of leverage to the people writing the check.
Two cautions. First, the rosy growth case assumes 10 percent compounding holds month after month, which almost nothing does forever. Stress-test your runway at half that growth and at zero, and plan against the pessimistic line. Second, the headline figure here can show break-even being reached and call runway effectively infinite, but that holds only if growth and margins behave. Bootstrapped businesses with no investor backstop should target a longer cushion, often 24 months or more, because there is no rescue round waiting.
Should I count an expected funding round in my runway?
No. Runway should reflect only cash you already hold and revenue you reasonably expect to collect. Money that has not cleared is not runway. Treating a hoped-for round as cash on hand is how teams discover too late that the bridge they were counting on never got built.
What burn rate is healthy for an early-stage startup?
There is no universal number, because it scales with the round you raised and the milestones you owe investors. The more useful test is the ratio of burn to progress: every dollar of net burn should buy measurable movement toward your next valuation milestone. Burn that funds headcount without moving the metrics that justify the next round is the dangerous kind.
Does this calculator account for one-time expenses?
It models a steady monthly burn, so lumpy costs like an annual software renewal or a tax payment are not captured separately. The honest workaround is to spread known one-time costs across the months and add them to your monthly expense figure, which pulls the runway estimate toward reality.