Cash Runway Calculator
Calculate how many months a startup can operate before it runs out of cash at its current burn rate. Essential for fundraising timing and budgeting decisions.
Last updated: May 2026
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About this calculator
Cash runway is the number of months a company can keep operating before it exhausts its cash, assuming spending continues at the current pace. The calculation is runway = cash on hand ÷ net monthly burn, where net monthly burn is the amount of cash the business loses each month (total cash outflows minus cash inflows from revenue). It is one of the most important survival metrics for any startup or cash-consuming business, because it answers the existential question of how long you have before you must either reach profitability or raise more money. 'Net' burn is the right figure to use: a company spending $120,000 a month but collecting $70,000 in revenue has a net burn of $50,000, not $120,000. Founders typically aim to keep at least 12–18 months of runway, because fundraising takes months and investors are wary of companies running on fumes. Edge cases: a company that is cash-flow positive has a negative or undefined net burn and effectively infinite runway, so the metric only applies while you are losing money; and runway assumes burn stays constant, which is rarely true — hiring, marketing pushes, or revenue growth all change it. Because of this, runway should be recalculated whenever spending or revenue shifts materially, and stress-tested against slower-than-expected revenue. It is a snapshot, not a forecast, but it is the snapshot that determines how urgently you need to act.
How to use
Example 1 — a startup with $500,000 in the bank burning $50,000 net per month. Enter Cash on Hand = 500000 and Net Monthly Burn = 50000. Runway = 500000 / 50000 = 10 months. Verify: with 10 months of cash, the founders should already be planning a raise or a path to profitability, since closing a round typically takes three to six months. Example 2 — a company with $1,200,000 in cash burning $80,000 net per month. Enter 1200000 and 80000. Runway = 1200000 / 80000 = 15 months. Verify: 15 months sits comfortably in the recommended 12–18 month window, giving the team room to hit milestones before needing to fundraise from a position of strength.
Frequently asked questions
What is the difference between gross burn and net burn?
Gross burn is your total monthly cash outflow — everything you spend on salaries, rent, software, and so on — while net burn subtracts the cash you bring in from revenue. Net burn is the correct figure for runway, because revenue genuinely extends how long your cash lasts. A company with $100,000 gross burn and $60,000 in monthly revenue has a net burn of only $40,000, and using the gross figure would understate its runway by a wide margin. Track both: gross burn shows your cost base, while net burn shows your actual cash depletion. Mixing them up is a common and consequential error in board reporting.
How much runway should a startup keep?
A common guideline is to maintain at least 12 to 18 months of runway, and to start raising your next round when you have roughly 6 to 9 months left. The reason is timing: fundraising typically takes three to six months, and you never want to negotiate from a position of desperation with only weeks of cash remaining. Investors also scrutinize runway closely, and a company with ample runway has far more leverage and credibility. The exact target depends on your stage, market conditions, and how predictable your revenue is. When in doubt, give yourself more buffer than feels strictly necessary, because raises almost always take longer than planned.
What happens to runway if my burn rate changes?
Runway is inversely proportional to burn, so increasing your spending shortens it sharply while cutting costs extends it. Doubling your net burn halves your runway; cutting burn by a third extends runway by roughly half. This is why cost discipline is the fastest lever a struggling company has — layoffs and spending cuts can buy months almost immediately. Conversely, growing revenue lowers net burn and stretches runway without cutting costs, which is the healthier path when achievable. Because burn rarely stays flat, you should recalculate runway whenever you make a significant hiring, marketing, or revenue change rather than trusting an old figure.
When should I NOT rely on a simple runway calculation?
This calculation assumes a constant burn rate, so it is unreliable for companies whose spending or revenue is changing quickly — a rapidly growing startup or one about to ramp hiring needs a month-by-month cash-flow projection instead. It also ignores the timing of large lumpy outflows (annual software renewals, tax payments) or inflows (a big customer prepayment), which can cause you to run out of cash earlier or later than the average suggests. It does not account for committed but unspent funds, lines of credit, or expected receivables. And it says nothing about whether you can actually raise more money. Treat the single-number runway as a quick gauge, and build a detailed cash-flow model for real planning.
Can a company have infinite runway?
Effectively yes — a company that is cash-flow positive, meaning its revenue exceeds its cash expenses, has a negative net burn and is no longer depleting its reserves, so the runway concept stops applying. At that point it is generating cash rather than consuming it, and the relevant questions shift to growth and profitability rather than survival. This calculator only gives a meaningful result while net burn is positive; if you enter a non-positive burn, the metric is undefined. Reaching cash-flow positivity (sometimes called 'default alive') is a major milestone precisely because it removes the existential clock that runway represents. Many startups deliberately manage toward it to escape dependence on fundraising.