Startup Runway Calculator
This free startup runway calculator tells you how many months your cash will last at your current burn rate. Enter your cash on hand, monthly burn, and monthly revenue to get your runway in months, your net monthly burn, and your projected zero-cash date.
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Your results
Enter your numbers to see your runway and zero-cash date.
How to use this calculator
Enter your cash on hand — the total cash the business can spend, usually your bank balance minus any reserves you refuse to touch. Then enter your monthly burn, everything you spend in a typical month: payroll, rent, software, advertising, and contractor fees.
If you have any incoming revenue, enter it as monthly revenue (pre-seed startups often leave this at zero). The calculator subtracts revenue from burn to find your net burn, then divides your cash by that number to give you months of runway and the date your cash runs out.
The results update instantly as you type, so you can play with scenarios: what if we cut $3,000 of burn, or land one more paying customer? A few small changes can move your zero-cash date by months.
How it works
The math is simple division. Net monthly burn is your gross monthly spending minus your monthly revenue:
net burn = monthly burn − monthly revenue
Your runway is your cash divided by that net burn:
runway (months) = cash on hand ÷ net monthly burn
If net burn is zero or negative, revenue covers all spending — you are cash-flow positive, so the calculator reports your runway as indefinite instead of a number of months. The zero-cash date is today plus the runway, using an average month of 30.44 days, so it is an estimate, not a promise.
Estimate only: assumes burn and revenue stay constant and there is no new funding, debt, or one-off expenses. Re-run monthly as your numbers change.
Frequently asked questions
How is startup runway calculated?
Runway is calculated by dividing your cash on hand by your net monthly burn (monthly spending minus monthly revenue). For example, $120,000 in the bank with a net burn of $10,000 per month gives 12.0 months of runway.
What is a good runway for a startup?
Most investors and founders aim for 12 to 18 months of runway, which is roughly the time needed to reach the next meaningful milestone or fundraising round. Less than 6 months is generally considered the danger zone where you should cut burn or raise immediately.
What is the difference between gross burn and net burn?
Gross burn is your total monthly spending — payroll, rent, tools, everything going out. Net burn is gross burn minus monthly revenue, i.e. how much cash the business actually loses each month. Runway is based on net burn because revenue offsets your spending.
What happens if my monthly revenue is higher than my burn?
Then your net burn is zero or negative, which means you are cash-flow positive and your runway is indefinite — you are adding cash rather than consuming it. This calculator shows that as an indefinite runway rather than a number of months.
Is the zero-cash date exact?
No — it is an estimate. The calculation assumes your burn and revenue stay constant, with no fundraising, loans, one-time expenses, or growth. Real burn fluctuates, so treat the date as a planning signal and re-run the numbers monthly.