Free runway calculator

How this runway calculator works

It projects your bank balance forward month by month. Gross burn compounds by the growth rate you give it, revenue is held flat as a deliberate margin of safety, and the month the balance crosses zero is your zero-cash month. If revenue covers burn on every projected month, you are default alive and the answer is not a date at all.

The simulation matters because the naive version - cash divided by today's burn - assumes you never hire again. Almost nobody's burn is flat. A team adding two engineers a quarter can lose three or four months of real runway versus the naive number, and those are exactly the months a raise needs.

The third card is the one to act on. A round takes about six months from first email to money in the account, so the calculator subtracts six from your zero-cash month and calls that your start-raising date. How the six months actually get spent is mapped in the fundraising process guide, and the pipeline maths behind it lives in how many investors you need in your pipeline.

Frequently asked questions

What is startup runway?

Runway is how many months of cash you have left at your current net burn: cash in the bank divided by what you lose each month after revenue. It is the single number that decides when you must raise, cut, or reach profitability.

What is the difference between gross burn and net burn?

Gross burn is everything you spend in a month. Net burn is gross burn minus revenue - the amount your bank balance actually falls. A company spending $80k with $30k of revenue has a gross burn of $80k and a net burn of $50k, and it is the $50k that eats runway.

When should I start raising?

Work backwards from your zero-cash month. A raise realistically takes about six months from first outreach to money in the bank, so start when you have nine or more months left and treat six as the alarm. Raising with three months of cash is negotiating with your back against the wall, and investors can smell it.

What does default alive mean?

Paul Graham's test: on current growth and burn, do you reach profitability before you run out of money? If revenue already covers burn, you are default alive - your runway is effectively infinite and fundraising becomes optional, which is the strongest position to raise from.

Why does the calculator ask for burn growth?

Because burn is rarely flat. If you are hiring, next year's burn is higher than this month's, and dividing cash by today's burn flatters you. Even 3% monthly growth compounds to about 43% higher burn in a year, which can quietly remove several months of runway.