About this tool
Runway calculator, explained
Runway is the number of months a company can keep operating before its cash runs out. This calculator counts it month by month from your cash, your revenue and cost lines, planned hires and a funding round, and draws the cash balance so you can see when it crosses zero.
How to use it
- 1Enter your Cash in the bank and the month the plan starts, or load the Pre-seed, Seed or Series A starting point.
- 2List your revenue and costs per month, one line each with its own monthly growth, for example subscriptions, payroll, office, software and marketing.
- 3Add planned hires with their monthly cost and start month, and a funding round with the amount and the month the money arrives.
- 4Read the result at the top and the scenarios below it: revenue stays flat, no new hires, no funding round. Switch between the Cash, Flows and Table views and a 2, 3 or 5 year horizon.
How it works
How runway is calculated
Each month, every revenue line and cost line is its starting amount grown by its own monthly rate for the months elapsed. Hires add their monthly cost from their start month onward. The month's net, revenue minus costs, is added to the cash, and the funding round is added in the month it arrives.
The result takes one of three forms. Default alive: revenue covers costs before the cash runs out, and the headline shows the month it happens. Runway in months: the cash goes below zero first, the headline shows the full months it covers, and the sentence under it gives the monthly revenue growth, applied to every revenue line, that would reach profit first. If neither happens within the horizon, the result reads 36+ months (or 24+ or 60+), with the burn still left at the end.
With the Seed starting point, $600,000 in cash, $18,000 of revenue growing 6% a month and $55,000 of monthly costs, plus an engineer at $11,000 a month from month 6, net burn is $37,000 in the first month and the cash lasts 19 full months.
With no growth, no hires and no funding, the result matches the classic formula, cash divided by net burn. The scenario tiles rerun the same plan with one change each, so you can see what a hire or a round is worth in months. Copy summary, Copy link, Download CSV and Print or PDF keep the plan, and the link holds every line, so opening it restores the same plan.
Each month: cash = cash + revenue - costs (+ funding in its month), where each line = starting amount × (1 + its monthly growth)^(months elapsed). With no growth: runway ≈ cash / (costs - revenue).
When to use it
Ways people use it
Monthly investor and board updates
Report runway from real numbers every month, with the chart showing where cash is heading and the table month by month.
Timing a fundraise
See how many months are left before cash gets tight, then add the round in the month you expect it to close and check the plan still holds if it slips.
Planning a hire
Add the hire with its start month and compare the result with the No new hires tile to see how many months of runway it costs, before you make the offer.
Testing a slowdown
The Revenue stays flat tile shows how much runway you have if sales stall. Lower a line's growth below zero to model revenue that shrinks.
FAQ
Questions people ask
How do you calculate startup runway?
Divide your cash in the bank by your net monthly burn, which is spend minus revenue. With $600,000 in cash, $55,000 of monthly spend and $18,000 of revenue, net burn is $37,000 and runway is about 16 months before any revenue growth. In this calculator's Seed plan, 6% monthly growth stretches that to 19 months, even with a hire in month 6.
What is the difference between gross burn and net burn?
Gross burn is everything you spend in a month. Net burn is that spend minus the revenue that comes in. Runway is based on net burn, because revenue offsets part of the spending.
How much runway should a startup have?
Enough to reach the next milestone that lets you raise again or become profitable, plus the months a fundraise takes. A raise takes months, so start well before cash runs low.
What does default alive mean?
A term from Paul Graham: a startup is default alive if, at its current spending and revenue growth, it reaches profitability before the money runs out. This calculator says Default alive when that happens within the horizon, and otherwise gives the revenue growth that would get you there.
How can I extend my runway?
Spend less, grow revenue faster, or raise more cash. Lower a cost line, raise a revenue line's growth, push a hire back or add a round, and compare how many months each change buys you.