Runway is the number of months a company can keep operating before its cash runs out. It is calculated by dividing the cash the company holds by the amount of cash it loses in a month. Runway is arithmetic, not an accounting standard, so the answer depends entirely on which cash figure goes into the top of the fraction and which loss figure goes into the bottom.
That is why two founders can describe the same bank balance and quote wildly different runways without either of them lying. This page explains the calculation, then explains the assumptions inside it that change the answer.
What is runway in startup finance, and what is it measured in?
Runway is measured in time, usually months. It answers one question: on current behavior, when does the money stop.
The standard form is:
Runway in months = cash on hand ÷ net monthly cash loss
Both inputs are choices, and both are contestable.
- Cash on hand normally means money the company can actually spend today: bank balances and instantly accessible deposits. It is not the same as assets, and it is not the same as the balance sheet's current assets, which include money other people owe you.
- Net monthly cash loss is the amount by which cash goes down in a month once money coming in is counted against money going out. That figure is the burn rate, and choosing the wrong version of it is the most common way a runway number goes wrong.
A company with money in the bank and no outgoings has infinite runway. A company that spends more than it receives has finite runway, and the calculation gives its length under one specific set of assumptions.
Is runway an official accounting term?
No. Runway does not appear in any accounting standard, no regulator defines it, and no auditor signs it off. It is internal management vocabulary that investors adopted, which is exactly why it travels between companies without a shared meaning.
The nearest formal concept is the going concern evaluation. Under the Financial Accounting Standards Board's standard on the topic, ASC 205-40, issued as ASU 2014-15 (read 2026-09-08), management has to evaluate whether conditions raise substantial doubt about the entity's ability to meet its obligations as they come due within one year after the financial statements are issued, and to disclose that doubt with its plans to address it if it is not alleviated.
That is worth knowing for two reasons. It is the one place where something like runway becomes a formal reporting obligation rather than a slide, and it fixes a horizon of one year, which is where a good deal of the folk wisdom about runway lengths quietly comes from. It is not a target, a benchmark, or a rule about how much cash a company ought to hold.
Why do two people calculate different runways from the same bank account?
Because at least five decisions sit inside the arithmetic, and none of them is visible in the answer.
| Decision | Longer runway if | Shorter runway if |
|---|---|---|
| Which burn is used | Net burn, after revenue is counted | Gross burn, ignoring revenue entirely |
| What revenue is assumed | Revenue grows, or is assumed to continue | Revenue is held flat, or removed |
| Whether an undrawn facility counts as cash | It is counted | Only drawn cash is counted |
| Whether signed commitments are counted | Only current spending is counted | Signed hires, leases and contracts are added |
| Which month is the base | An unusually quiet month | An average, or the next planned month |
The gap between the most generous and the most conservative version of these choices can be several months on identical facts. Nothing about a runway figure on its own tells a reader which version they are looking at, which is why the assumption list matters more than the number.
Does a credit facility or a signed term sheet count as runway?
This is where runway numbers most often overstate. Three cases come up repeatedly.
An undrawn credit facility is borrowing capacity, not cash. It usually carries conditions, covenants and a lender's right to decline further drawdowns if those conditions break, and the conditions tend to break in exactly the circumstances that make a company want to draw. Counting it as cash treats a conditional promise as a certainty.
A signed term sheet is generally not binding as to the investment itself. Money arrives at closing, after diligence and documentation, and closings slip. The standard documents used in United States priced rounds are published free by the National Venture Capital Association as its model legal documents (read 2026-09-08), and reading the sequence they describe makes clear how much has to happen between a signature and a wire.
Receivables are money owed, not money held. They convert into cash on the payer's schedule, and that schedule belongs to somebody else.
None of these is a reason to ignore them in planning. They belong in a plan as what they are, described with their conditions, rather than added to the cash line.
What actually changes the number?
Only two things change runway: cash in the top, or loss in the bottom.
Cash goes up when the company raises money, borrows, receives a grant, or collects from customers. Raising equity means selling part of the company, which is what the whole types of startup funding landscape is organized around. Borrowing raises cash without selling equity and creates a repayment obligation that will itself consume cash later.
In the United States, a private raise is made under an exemption from registration such as Rule 506(b) of Regulation D, which the SEC sets out on its Rule 506(b) page (read 2026-09-08) and which requires a Form D notice filing with the Commission after the first sale. Canadian issuers raise under provincial prospectus exemptions instead, so the paperwork and the filing are different even when the deal looks the same.
Loss goes down when the company spends less or receives more. Both take longer to arrive than a spreadsheet suggests. Payroll reductions carry notice periods and, in many places, statutory costs, so the month in which headcount falls is often a month in which cash goes out faster than usual. Contracts have terms. Revenue increases require the sales cycle to run its length first.
A company financed by venture capital usually plans a runway around the next raise, because that is where its cash is expected to come from. A bootstrapped company plans around collections, since the only external cash on the table is a customer's. Those are different planning problems that produce the same word.
What does runway look like before there is any revenue?
At the earliest stage there is nothing to net against spending, so gross and net burn are the same figure and runway is simply cash divided by monthly spending. That is the situation most pre-seed funding rounds are raised into, and it is the cleanest version of the calculation, because there are no revenue assumptions to argue about.
It also means the number is dominated by one line: what the founders pay themselves and anyone else. Runway at that stage is mostly a statement about compensation and one or two fixed contracts, and it moves fast when either changes.
What runway does not tell you
Runway is a division problem. It is silent on almost everything that decides whether the company is worth funding again.
It says nothing about whether the spending is producing anything. Two companies with identical runway can be in completely different positions, one building something customers pay for and one not. It says nothing about the quality of revenue, since a single customer who could leave and a diversified base net out the same way. It says nothing about obligations that fall outside the monthly average, such as an annual renewal, a tax payment or a deposit. And it assumes the future resembles last month, which is the assumption most likely to be wrong in a young company.
A number this simple is easy to quote and easy to over-read. It is a planning input, not a verdict.
This page explains a calculation and is not financial, tax, legal or investment advice. It does not say how much runway any company should hold, when to raise, or what to cut, because those depend on facts this page cannot see. Cash forecasts that a business will act on belong with a qualified accountant, and any financing that changes ownership or creates debt belongs with a qualified attorney before it is signed.
FAQ
How do you calculate runway in months? Divide cash on hand by the net amount of cash the business loses each month. Both inputs need stating: which cash is counted as available, and which burn figure sits in the denominator. A runway number quoted without those two definitions cannot be compared with anyone else's.
Should runway use gross burn or net burn? Both are used, for different purposes, and they answer different questions. Net burn produces the longer figure because revenue is subtracted from spending, so it depends on revenue continuing. Gross burn produces the shorter figure and answers what happens if revenue stops. Neither is the correct one in the abstract, and a plan that shows only one is showing half the picture.
Does runway include money that has been committed but not received? Cash that has not arrived is not cash on hand. Undrawn facilities, signed term sheets and unpaid invoices are conditional, and the conditions can fail. They belong in a forecast as separate, labeled lines with their conditions stated, rather than added to the balance a runway calculation divides.
Is runway the same thing as burn rate? No. Burn rate is a rate, measured in currency per month. Runway is a duration, measured in months, and it is the result of dividing cash by that rate. Burn rate is the input; runway is the output.
Who asks a startup for its runway? Investors, boards and lenders, because it sets the timetable for every other decision. Auditors ask a related but formal version of the question when they consider going concern. Anyone answering should say which assumptions the figure uses, since the same company can honestly report several different runways depending on the choices described above.