Tool · Investor Sam Biz

Startup Runway Calculator

June 30, 2026 • By the Investor Sam Editorial Team • Reviewed by Berly Sam Varghese, Editor
Runway is how many months your business can survive before it runs out of cash, and it is the number that should sit at the top of every founder's dashboard. It rests on two things: how much cash you have and how fast you are burning it after revenue. This calculator subtracts monthly revenue from monthly expenses to find your net burn, then divides cash on hand by that burn to give your runway. If revenue already covers expenses, you are cash-flow positive and runway is effectively unlimited.

Example: Cash on hand: 150000 $ · Monthly expenses (burn): 35000 $ · Monthly revenue: 15000 $

Runway7.5
Net monthly burn$20,000
Months until cash runs out7.5

Worked example

With $150,000 in the bank, $35,000 of monthly expenses, and $15,000 of monthly revenue, your net burn is $35,000 minus $15,000, or $20,000 a month. Dividing $150,000 by $20,000 gives 7.5 months of runway. That is the window in which you need to either raise more, cut burn, or grow revenue enough to close the gap, and it should drive your urgency.

Frequently asked questions

What is net burn versus gross burn?

Gross burn is your total monthly expenses; net burn subtracts revenue from expenses. Runway is based on net burn, since revenue offsets some of what you spend. This calculator uses net burn.

What if revenue exceeds expenses?

Then your net burn is zero or negative, you are cash-flow positive, and runway is effectively unlimited from operations. The calculator returns zero months of burn in that case.

How much runway should I keep?

A common target is 12 to 18 months, enough to hit milestones and raise the next round without negotiating from desperation. Below six months, cost cuts or fundraising usually become urgent.

Does runway account for growing expenses?

This is a snapshot at your current burn. If you plan to hire or spend more, model runway with your expected future burn, since rising expenses shorten runway faster than a flat estimate suggests.

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Sources

Berly Sam Varghese · Editor, Investor Sam

Berly Sam Varghese is an engineer who treats money the way he treats any hard problem — something to be engineered, not gambled on. He funded years of education and built real financial stability the patient way, by living below his means and investing rather than borrowing. He writes for the person building something and trying to keep the finances sane. He reviews and approves every article on Investor Sam and checks the figures against primary sources before anything is published. More about our standards.