Free runway calculator

Startup runway calculator

See how long your cash lasts, when it runs out, and whether current growth gets you to profitability first.

Cash runway

Calculate burn rate and runway

Enter this month's numbers and the month-over-month growth you expect. The model projects cash month by month for up to 10 years.

How this runway calculator works

This runway calculator starts with the standard burn formulas and then projects your cash balance month by month, so that growing revenue (or growing costs) is reflected in the answer:

  • Gross burn = monthly expenses
  • Net burn = monthly expenses − monthly revenue
  • Simple runway = cash ÷ net burn
  • Revenue in month n = revenue × (1 + revenue growth)^(n − 1), and the same for expenses

The projected runway is the point at which cumulative net burn exceeds your cash, including a fraction of the final month. The zero-cash month is shown as a calendar month counted from the current month. Projections stop after ten years.

Default alive or default dead

The default-alive check comes from Paul Graham's October 2015 essay, which asks: assuming expenses remain constant and revenue keeps growing at the rate it has over the last several months, does the company make it to profitability on the money it has left? The calculator marks you default alive when revenue catches up with expenses before cash runs out. Leave expense growth at 0% to apply the essay's assumption; raise it if you plan to hire.

Worked example

With $150,000 in the bank, $8,000 of monthly revenue, and $20,000 of monthly expenses, net burn is $12,000 and simple runway is 12.5 months. If revenue grows 5% a month and expenses stay flat, revenue covers expenses in month 20 and cash bottoms out at roughly $14,000 just before that: default alive, but with almost no margin. At 4% monthly growth the same company runs out of cash in month 17 and is default dead. Small changes in growth move the answer a lot, so test a conservative case.

Mistakes that make runway look longer than it is

  • Using gross revenue that has not been collected yet, or annual prepayments counted as monthly revenue.
  • Leaving out annual costs such as insurance, tax payments, or software renewals.
  • Assuming a growth rate that is a goal rather than a measured trend.
  • Ignoring the time a fundraise or acquisition takes; start well before the last few months.

Revenue quality matters too. Measure churn with the churn and retention calculator and growth with the MRR and ARR calculator. If you are weighing growth against profitability, the Rule of 40 calculator is a useful check.

Frequently asked questions

What is the difference between gross burn and net burn?

Gross burn is total monthly spending. Net burn is spending minus revenue, which is the amount your cash balance actually falls each month. Runway is usually calculated from net burn.

How do I calculate runway?

At a constant burn, runway equals cash divided by monthly net burn. With $150,000 of cash and $12,000 of net burn, runway is 12.5 months. This calculator also projects month by month so revenue and expense growth can change the answer.

What does default alive mean?

Paul Graham's definition asks whether, assuming expenses stay constant and revenue keeps growing at its recent rate, the company reaches profitability on the money it has left. Set expense growth to 0% to match that definition exactly.

What growth rate should I enter?

Use your actual average month-over-month revenue growth over the last several months, not a target. If growth has been uneven, try a conservative and an optimistic case and plan around the conservative one.

Should I include money I expect to raise?

No. Model the cash you have. Runway that depends on a raise that has not closed is a plan, not runway. Run a second scenario with the new cash added if you want to see the effect of a round.

Sources and further reading