Startups & business · Free tool
Runway calculator: how many months you really have
Enter a few numbers to see your base and stress runway, the month your cash runs out, and what a cut would change. Takes about 60 seconds.
- 1 min Quick · 4 min Detailed
- Beginner-friendly
- PDF report
Estimate, not advice. Simplified math from the numbers you enter, with the formulas shown below.
Your result
Your result appears here once the required boxes are filled.
Quick estimate See the defaults used
What this means
What to do next
Estimates and options to consider, not advice. Your situation may differ. Terms
The numbers
Technical breakdown
Breakdown
How these numbers are made
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How the runway formula works
Two parts of this calculator are standard definitions. The rest is this site’s conservative method, and it is labelled that way.
Standard. Net burn = cash out − cash in, per month. Runway = cash ÷ net burn.
This site’s method (a heuristic). Real cash = cash in the bank − cash you can’t count on − wind-down cost. Burn today = the worse of your 3-month and 6-month averages. If you enter a planned burn for 6 months from now, burn moves in a straight line to it and then stays flat. Base runway follows that path until the real cash is gone. Stress runway does the same after taking one shock out of the cash.
Worked example. Cash 900,000. Cash you can’t count on 150,000 (120,000 owed plus 30,000 of doubtful invoices). Wind-down cost 150,000. So real cash is 600,000. Burn is 45,000 over 3 months and 50,000 over 6 months, so burn today is 50,000. Base runway is 600,000 ÷ 50,000 = 12.0 months. With a 60,000 shock, stress runway is 540,000 ÷ 50,000 = 10.8 months. The bank balance alone would say 900,000 ÷ 45,000 = 20.0 months.
The monthly cut needed to reach a target is the total burn over that many months, minus your cash after the shock, divided by the months. In the example, 18 months needs (18 × 50,000 − 540,000) ÷ 18 = 20,000 a month. When the cut is more than half of your burn, the calculator says that cuts alone won’t get you there and you need cash.
What your number means
The zone is set by stress runway. These thresholds are rule-of-thumb lines drawn by the author, not benchmarks, and a company with predictable revenue can reasonably sit lower.
| Stress runway | Zone |
|---|---|
| 24 months or more | Fine if efficient |
| 18 to under 24 | Fundraising is worth starting |
| 12 to under 18 | Consider raising and freezing non-essential spend |
| 6 to under 12 | Consider cutting costs to extend runway |
| Under 6 | Consider talking to your board, investors or lender soon |
Each zone comes with three options to consider. They are options, not instructions, and they do not replace advice on your own situation.
Where to find each number
This page replaces the old paper worksheet, “The 11pm Runway Check”. The same questions are below, so you can gather the numbers first. Prefer paper? Fill in the form, then use Print for a one-page copy with your own numbers.
- Cash in the bank. Only money you could move tomorrow. A credit line you have not drawn is a promise from a bank, not cash.
- Cash you can’t count on. Add up three buckets: taxes you collected or withheld but have not paid over (payroll or sales tax), customer prepayments you might have to refund if they cancelled, and bills you have been stretching. Add invoices that are more than 60 days late, and anything a single customer worth over 10% of your yearly revenue still owes, until they reach the bank.
- Wind-down cost. What closing the company would still cost: severance, unused vacation paid out, the rest of a lease and of annual software contracts, and tail insurance. It belongs to closing the company, not to running it.
- Net burn. For each month, total money out minus total money in, from real bank numbers rather than the budget. Include debt repayments and leave out equity you raised. Average the last 3 months and, separately, the last 6. A 6-month average catches one-off events that flatter the 3-month figure.
- The one-time shock. Pick the single event you could least absorb in the next 60 days: your biggest customer paying 60 days late, a cloud or AI bill up 50%, a bank withdrawing your credit line, or a contract worth over 15% of revenue not renewing.
Early signs that show up before the bank balance does
Cash is a lagging signal. These four usually appear first. They are things to look at, not a score.
- Existing customers are spending less this year than last year, in total.
- Customers are paying more slowly: days to collect up by 10 or more against six months ago.
- Gross margin has dropped 2 points or more two quarters in a row, often from cloud or AI costs.
- Win rate is falling and deals are taking longer to close. Either one alone can be noise; both together may be a market signal.
If two or more of these are showing and your stress runway is under 12 months, that is a good moment to talk to your board, investors or lender, and to your own advisor.
What this calculator does not do
- It is not a forecast. It follows the burn you enter, with no revenue growth model.
- It treats the shock as one payment taken from cash at the start of the stress case.
- It never adds a credit line or committed funding to the main runway.
- The burn multiple, shown if you enter net new recurring revenue, is a measure, not a score. No benchmark is implied.
Frequently asked questions
How do you calculate cash runway?
Runway is cash divided by net burn. Net burn is cash out minus cash in per month. If you have 600,000 and lose 50,000 a month, you have 12 months. This calculator also takes out cash you cannot count on and the cost of closing the company, then follows your burn as it changes.
What is the difference between base runway and stress runway?
Base runway uses your real cash and your burn path. Stress runway takes one bad event out of the cash first, such as a tax bill or a lost customer in the next 60 days. Both are shown with equal weight because the truth usually sits between a hopeful number and a cautious one.
Should I count my credit line in my runway?
The calculator never adds it to the main runway. A line you have not drawn is a promise, not cash, and it can be withdrawn or restricted. If you enter one under Advanced, it is shown as a separate “with facility” line.
How early should I start raising?
There is no standard answer. The calculator shows the latest sensible start: the month your stress case runs out, minus your own fundraising lead time (6 months unless you change it), minus a 3-month buffer. It reads “Now” whenever your stress runway is 18 months or less. Treat all of it as a rule of thumb and replace the lead time with your own experience.