Runway calculator
How many months of cash you’ve got left, and roughly when it runs out. It’s free, there’s no signup, and nothing you type gets saved.
Use any currency, just keep all three the same.
Nothing you type here gets saved or sent anywhere.
How runway is worked out
Runway is one division, and that’s genuinely all it is. Take the cash you actually have in the bank, divide it by what leaves each month once revenue is accounted for, and you’ve got the number of months before the account hits zero.
runway in months = cash on hand / (monthly expenses - monthly revenue)
The denominator is your net burn, and it’s the part founders get wrong. Gross burn is everything you spend. Net burn is what you spend minus what you earn, and net burn is what runway depends on. Let’s say you’re spending 40,000 a month and bringing in 25,000. You’re burning 15,000 net, so you last exactly as long as a company spending 15,000 and earning nothing.
When revenue covers the burn, net burn drops to zero or below, the division stops meaning anything, and the calculator says so rather than printing some enormous number. You’re cash-flow positive at that point, and runway isn’t the thing limiting your plans any more.
What the number is actually for
The point of runway is to set dates. When you start raising, when a hire stops being affordable, and when a plan has to change instead of being repeated. Most founders work it out once, screenshot it, and never touch it again, which is how you end up at four weeks of cash trying to negotiate a term sheet.
It’s worth doing with the person you’re building with in the room. You’ll disagree about burn long before you disagree about strategy, and burn is the cheaper argument to have early. Write down what you both counted as an expense while you’re at it, because that is usually where the two numbers came apart.
The other figures in a co-founding deal move with this one: how much of the company you each own, what a round does to that, and how much has actually vested so far. Those calculators are in the app, next to the legal templates and the guides. See the full set.
Frequently asked questions
- How is startup runway calculated?
- Runway is cash on hand divided by net monthly burn, and net burn is your total monthly expenses minus your monthly revenue. So 120,000 in the bank against 15,000 of net burn gives you 8 months. If revenue covers the burn, net burn is zero or below and there's no end date left to work out.
- What counts as burn?
- Everything that leaves the bank in a normal month: salaries and contractors, rent, software, hosting, marketing, accounting and legal. Use the real number rather than the budget, they're rarely the same. For example, if you know a hiring push or an annual renewal lands in March, run the number again with the burn raised for that month instead of smoothing it across the year.
- Should I include revenue?
- Include revenue you're confident will repeat. The calculator subtracts it from burn to get net burn, so overstating it flatters your runway in exactly the place you least want to be wrong. If your revenue is lumpy, run it twice, once with revenue and once without, and plan against the shorter answer.
- How much runway should a startup have?
- Most advice says start raising at around six months left, since a round typically takes three to six months to close, and four weeks of cash is not a position you want to be negotiating a term sheet from. That's why 12 to 18 months after a raise is what founders tend to aim for. There's nothing magic about the number, it just leaves room for one plan to fail.
- What's the difference between gross burn and net burn?
- Gross burn is everything you spend in a month. Net burn is what you spend minus what you earn. Runway runs on net burn, which is why a company with high spend and real revenue can have more runway than a leaner one with none.
- Which currency should I use?
- Any of them. The calculator works in plain numbers, so the answer is the same in dollars, euros or pounds, as long as all three inputs use the same one.