Startup runway is the number of months your company can operate before the cash hits zero. The formula is cash in the bank divided by monthly net burn. A company with ₹1.2 crore and a net burn of ₹14 lakh has 8.6 months of startup runway. That sounds workable, but one founders’ guide says a fundraise takes six to nine months on average.
In other words, that founder is already late. This guide shows how to calculate your startup runway, stress-test it with the calculator below, and decide when to start raising.
What startup runway actually means
Runway measures time, not money. It tells you the date your bank balance runs out if nothing changes. Three terms drive the calculation:
- Cash: the money in your bank accounts today, not the invoices you hope to collect.
- Gross burn: everything you spend each month, before counting any revenue.
- Net burn: gross burn minus the revenue you actually collect. This figure drains your account.
Runway uses net burn, not gross burn. A company that spends ₹18 lakh a month and collects ₹4 lakh has a net burn of ₹14 lakh. That is the amount leaving the account every month.
How to calculate your startup runway in 3 steps
- Find your cash. Add up the balance across every bank account today.
- Find your monthly net burn. Average your spending over the last three months and add one-twelfth of any annual bills. Then subtract the revenue you actually collected.
- Divide cash by net burn. ₹1,20,00,000 divided by ₹14,00,000 gives 8.6 months.
Round down when you plan, because eight months is a safer number to build a hiring plan on than 8.6. Next, test how fragile that number is.
Stress-test your startup runway
Your base case is the most flattering version of the truth. The tool below runs three scenarios: your numbers today, costs up 20%, and revenue down 20%. It works in your browser, and Modelodge stores nothing you type. The starting figures match the example above, so replace them with your own.
Runway stress test
Enter amounts in rupees. Revenue means money you actually collected. Nothing leaves your browser.
TODAY
months
COSTS +20%
months
REVENUE -20%
months
Verdicts follow the raising milestones in the timeline section below. They are planning guides, not financial advice.
Read the worst scenario first. According to one startup runway guide, your position is sound if the downside case still leaves 12 months or more when you start raising.
4 traps that make your runway look longer than it is
- Counting invoices as cash. An invoice is a promise, not money, so count it only when it reaches your bank account.
- Ignoring planned hires. Three hires at ₹1.5 lakh a month each lift the example net burn from ₹14 lakh to ₹18.5 lakh. Runway then drops from 8.6 months to 6.5 months.
- Forgetting annual and tax bills. GST payments, TDS deposits and yearly software plans arrive in lumps. Spread them across 12 months so they do not ambush you.
- Treating runway as a fixed number. Runway is a calendar date, and every hire, discount or late payment moves it. Recalculate it every month.
How to extend your runway without stalling growth
Runway grows in three ways: you cut burn, raise revenue or raise cash. Cutting is the fastest. Trimming the example net burn from ₹14 lakh to ₹12 lakh stretches 8.6 months to 10 months.
Start with the quiet leaks. A weekly 30-minute status meeting with 8 people adds up to about 192 paid person-hours a year, as Modelodge’s weekly status meeting cost breakdown shows. A written update can do the same job for a fraction of that cost.
Next, check what you pay vendors. Elon Musk’s idiot index divides the price of a finished part by the cost of its raw materials, so a ₹100 bracket sold for ₹5,000 scores 50. Ask the same question about agencies and software: what would the cheapest honest version cost?
When to start raising: a startup runway timeline
Most founders start too late. One guide says to begin raising when you have 12 to 18 months left. Another gives a milestone ladder for the months that follow:
- 12 months: plan your next raise.
- 9 months: be in active investor conversations.
- 6 months: be in full raising mode, with a bridge plan ready.
- 3 months: you are in emergency mode.
These benchmarks come from published founder guides, not from your market, so adjust them to what investors tell you. Still, the logic holds. Raising takes months, and a short runway weakens your hand at the table.
Run your numbers this week
Enter your real figures in the calculator above. If your downside scenario shows fewer than 12 months, put “start raising” on the calendar now. Then recalculate your startup runway on the first day of every month.
Startup runway questions
What is a good startup runway?
A good startup runway after closing a round is about 24 months. One founders’ guide treats anything under 18 months at close as a warning sign for investors. Between rounds, aim to start your next raise with at least 12 months left.
How do you calculate startup runway?
Divide your cash in the bank by your monthly net burn. Net burn is gross monthly spending minus the revenue you actually collect. With ₹1.2 crore in cash and ₹14 lakh of net burn, runway is about 8.6 months. Round down when you plan.
What is the difference between burn rate and runway?
Burn rate is how much cash you lose each month, while runway is how many months you can keep losing it. Gross burn counts all spending. Net burn subtracts collected revenue. Divide cash by net burn to turn your burn rate into runway.
When should a startup start fundraising?
Start raising when you have 12 to 18 months of runway left. Rounds take six to nine months on average, so waiting until six months remain can leave you accepting whatever terms investors offer, according to one founders’ guide. Start earlier than feels necessary.
Does revenue count towards startup runway?
Yes, but only the revenue you have collected. Subtract the cash customers actually paid from your gross burn to get net burn. Unpaid invoices and forecast sales do not count until the money reaches your bank account, so leave them out of the calculation.
Sources
- The Complete Founders’ Guide to Burn Rate and Runway (Puzzle): runway formula, gross versus net burn, fundraising timing.
- Runway: definition, the 24-month rule, and how to read the calendar that actually matters (Startups.com, via Launchrock): runway milestones and stress-test scenarios.
- Modelodge posts linked above: the meeting cost and idiot index figures come from those posts.
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