Free tool
Burn Rate & Startup Runway Calculator
Work out how many months of cash you have left, the month you run out, and what revenue growth does to both.
How long your cash lasts at the current burn, and the month it runs out — the date every other decision gets scheduled against.
- Cash in the bank
- Monthly revenue
- Monthly expenses
- Monthly revenue growth
Calculate runway
Example
Cash in the bank $250,000 · Monthly revenue $8,000
9 months, 1 week
Runway
Position Tight
How it works
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1
Enter your numbers
Fill in cash in the bank, monthly revenue, monthly expenses and monthly revenue growth. Change a number and the answer updates.
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2
Press calculate runway
One button. Change any input afterwards and the answer updates as you type.
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3
Read the result
You get runway, plus net monthly burn, zero-cash date.
How runway is calculated
Runway is how many months you can keep operating before cash reaches zero. The basic formula is cash divided by net monthly burn, where net burn is monthly expenses minus monthly revenue.
If you have $250,000 in the bank, spend $35,000 a month and collect $8,000 a month, your net burn is $27,000 and your runway is about nine months.
That formula quietly assumes revenue never changes. Once you add a growth rate, burn shrinks every month and the simple division understates how long you have — sometimes by a wide margin. This calculator switches to a month-by-month projection as soon as you enter a growth rate, and tells you the month revenue overtakes expenses.
What counts as burn
Use cash actually leaving the bank, not accounting expense. The two diverge in ways that matter: annual software billed upfront, contractor invoices paid in arrears, and payroll taxes remitted quarterly all hit cash on a different schedule than they hit your P&L.
- Include salaries, contractors, payroll taxes, infrastructure, software, rent and marketing spend.
- Include founder salaries if you are paying them — a model that assumes unpaid founders forever is not a model.
- Exclude depreciation, amortisation and other non-cash entries.
- Exclude one-off outflows you will not repeat, or model them separately.
Gross burn vs net burn
Gross burn is everything going out. Net burn is what goes out after revenue comes in. Runway is always calculated on net burn, but investors will ask for both, because a company with $200k gross burn and $190k revenue is in a very different position from one with $10k gross burn and no revenue, even though both net to $10k.
How much runway you should hold
The common guidance is 18 to 24 months after a raise, and never letting the balance fall below six months without a live plan to change it. The reason is timing: a seed or Series A process typically takes three to six months from first meeting to cash in the bank, and it goes slower precisely when the market is bad.
Raising with three months left means negotiating from a position where you cannot walk away, and sophisticated investors can see that in your bank statements. Start the conversation while the number on this page still looks comfortable.
Default alive or default dead
Paul Graham's framing is the most useful test here: if your current growth rate and current costs carry you to profitability before the cash runs out, you are default alive. If not, you are default dead and are relying on a future raise you do not yet have.
Enter your real monthly growth rate above. If the break-even month arrives before the zero-cash date, you are default alive — which is the single strongest position you can negotiate a round from, because you no longer have to.
What this does not do
- Holds monthly expenses flat. Most startups add cost as they grow, so a growth projection is an optimistic ceiling rather than a forecast.
- Assumes cash goes out evenly. Annual software, tax bills and hiring all land in lumps, and a lumpy month can end the runway earlier than the average suggests.
- Does not know about money you have not received. Signed contracts, invoices in arrears and a pending raise all change the picture.