Burn Rate & Runway Calculator
Enter your cash, monthly spend and revenue to see your net burn and exactly how many months of runway you have — live.
- Free — no sign-up
- Instant, on-screen results
- Built by our CA · CS team
- Rules cited on the page
Enter your figures — the result on the right updates as you type.
How your runway is calculated
Extend your runway with a virtual CFO
We help startups cut burn, model scenarios and time the next raise — book a review.
Disclaimer: Indicative estimate based on a constant monthly net burn. Real runway changes with revenue growth, one-time costs, hiring and seasonality. Use it as a planning guide, not a guarantee.
Burn rate & runway — the survival math
Your burn rate is how fast you spend cash; your runway is how long that cash lasts. Gross burn is your total monthly spend; net burn is spend minus revenue. Divide your cash by net burn and you get the number that matters most to every founder: how many months until zero.
How the calculator works
The formulas are simple, and that is the point — clarity beats complexity when your company's life is on the line.
| Gross burn | = Monthly operating expenses |
| Net burn | = Expenses − Revenue |
| Runway (months) | = Cash ÷ Net burn |
| Runway (years) | = Runway months ÷ 12 |
| If Net burn ≤ 0 | = Profitable · infinite runway |
Worked example
A seed-stage startup holds ₹50,00,000 in the bank, spends ₹8,00,000 a month and collects ₹3,00,000 in revenue. Here is the runway math step by step:
Key terms explained
Gross burn vs net burn
Gross burn is your total monthly cash outflow — every rupee that leaves the bank. Net burn subtracts the revenue you collect, so it reflects the real hole you fill each month. Runway is always driven by net burn.
Runway
The number of months your cash lasts at the current net burn: cash ÷ net burn. If you burn ₹5L a month and hold ₹50L, you have 10 months. Watch it monthly — a jump in spend shortens it fast.
Default-alive vs default-dead
Coined by Paul Graham: you are default-alive if, on current growth and burn, you reach profitability before the cash runs out — otherwise you are default-dead and must cut burn or raise now.
Fundraise timing
Raising takes longer than founders expect. Start 3–6 months before you hit zero so you negotiate from strength, not desperation. Fundraising with under 3 months of runway crushes your valuation and leverage.
Questions people ask
Short answers on Burn Rate & Runway Calculator. Tap a question to open it.
01What is the difference between gross burn and net burn?
Gross burn is total monthly cash spend. Net burn is that spend minus monthly cash revenue — the amount by which your bank balance actually falls each month. Runway is calculated on net burn.
02How is runway calculated?
Runway in months = cash in bank ÷ monthly net burn. If you are cash-flow positive there is no burn and runway is effectively unlimited at the current run rate.
03How much runway should a startup keep?
Investors commonly look for 12 to 18 months, which is enough to hit the next set of milestones and still leave three to six months to close a round. Below six months, fundraising leverage drops sharply.
04Should burn be calculated on cash or on accrual profit?
On cash. Runway is a treasury question, so use actual bank movements including tax payments, capex and collections timing — not the accounting profit or loss.
05What if my burn changes every month?
Use the average of the last three months rather than the single latest month, and re-run the number whenever you add headcount or a large recurring cost.
More Startup & Funding tools
Picked from the same shelf. Every tool is free and runs in your browser.
Disclaimer: This tool gives indicative results for general guidance only and is not professional advice. Please verify with a qualified CA before acting on the numbers.