Stage 1 · Build the model

Startup Runway Calculator

How many months your cash lasts, your cash-out month, and whether you are default alive.

Free, no sign-up. Your numbers stay in your browser.

Please note. This tool is for education and planning. It gives estimates, not financial advice. Results are estimates based on what you enter. Full disclaimer · How we build the numbers

What this tool does

Runway is how many months your cash lasts at your current burn. Because revenue and costs both change, a simple 'cash ÷ burn' can be months off. This calculator projects both, month by month.

How to use it

Enter today's bank balance, monthly revenue and total monthly costs.
Add realistic monthly growth for revenue and costs.
Read your runway, cash-out month and whether revenue overtakes costs first.

The maths, in plain view

Net burn = monthly costs − monthly revenue
Cash(m) = Cash(m−1) + Revenue(m) − Costs(m)
Runway = months until Cash(m) < 0

A worked example

With $450k in the bank, $18k of revenue growing 6% a month and $62k of costs growing 2% a month, net burn is $44k today. Cash runs out in month 11, but revenue only overtakes costs in month 34, so the company is default dead: it needs to raise, or cut burn, well before month 11.

Tips

Use costs you actually pay, including payroll taxes and software.
Re-run it each month with actuals: runway is a moving number.

Want the full story? Read How much runway a startup needs, and when to start raising.

Questions people ask

How many months of runway should a startup have?

A common rule of thumb is 18-24 months after a raise, and never fewer than 6-9 months when you start the next round, because fundraising usually takes 3-6 months.

What is the difference between gross burn and net burn?

Gross burn is everything you spend in a month. Net burn is spending minus revenue: the cash you actually lose each month. Runway uses net burn.

What does default alive mean?

A startup is default alive if, at its current growth and costs, revenue overtakes costs before the cash runs out. If not, it is default dead and needs to raise money or change the plan.

Keep going

Stage 2 · Plan the raise