Cash runway is the number of months a company can keep operating before its cash hits zero, if spending stays where it is and no new money comes in. To calculate it, divide the cash on hand by the net cash the company burns each month. A company with $4.2 million in cash and $350,000 of net monthly burn has roughly 12 months of runway.
That is the whole formula. The skill is in choosing the right inputs, smoothing out bumpy months, and knowing what the answer does and does not tell you. This guide covers all three, with worked examples for founders and for investors who want to check a stock's staying power.
TL;DR
- Formula: Cash runway (months) = cash available ÷ net monthly cash burn.
- Net burn is cash going out minus cash coming in. Gross burn ignores revenue and gives a shorter, more pessimistic number.
- Bumpy burn: divide by a trailing three-month average, not one month, so invoice timing does not swing the result.
- For investors: a runway of 12 months or less raises the odds of a stock offering and dilution, but the number is a snapshot, not a forecast.
- If net burn is zero or negative, the company is not burning cash and runway is not the right question.
Table of Contents
- What cash runway means
- The formula
- Worked examples
- When burn changes from month to month
- Negative burn: when runway does not apply
- Where investors find the inputs
- How to read the result
- What runway cannot tell you
- Runway beyond startups: personal and property investing
- Common mistakes
- Put the numbers to work
- FAQ
- Sources
What cash runway means
Runway is a countdown. It answers one question: how long until the money is gone? Investing.com's investor guide describes it as the time, usually in months, that a company can operate before depleting its cash reserves, assuming it keeps its current rate of spending and raises no capital.
The term comes from startup finance, where a young company spends more than it earns and lives off money raised from investors. But the logic applies to any business with negative cash flow: a biotech with no product yet, a growth-stage software firm, a small business in a slow season. If you own shares in companies like these, runway tells you how much time management has before it must raise money, cut costs or reach profitability.
The formula
The standard version is short:
Cash runway = cash available ÷ net monthly cash burn
Workday's guide to cash burn states it exactly that way. Capital One's business guide phrases it as current cash balance divided by monthly cash burn rate. Investing.com's version uses cash and cash equivalents over the monthly burn rate. The wording differs, the math does not.
Step 1: Find the cash
Use cash and cash equivalents: money in the bank plus very liquid holdings that convert to cash quickly. For a private business, that is your bank balances. For a public company, it is the top of the balance sheet in the latest quarterly report.
Be honest about what is really yours. FoundersCPA points out that a raw bank balance can overstate usable runway when credit card balances and drawn credit lines are owed. Subtract short-term obligations you must pay soon, and your runway is more believable.
Step 2: Calculate the burn
There are two kinds of burn, and mixing them up is the most common mistake.
- Gross burn is total cash going out in a period. Workday defines it as cash paid out for operating purposes, excluding non-cash items such as depreciation and amortization.
- Net burn subtracts inflows such as customer payments: cash outflows minus cash inflows.
Investing.com notes that net burn is the usual choice for runway because it reflects how fast the cash pile actually shrinks. Wall Street Prep frames the same split for early-stage companies: gross burn is monthly cash expenses, and net burn is cash sales minus cash expenses, read as a negative number when the company loses cash.
A quick way to measure it without any modeling: take cash at the start of the month, subtract cash at the end, and make sure no financing came in during that month. The difference is that month's net burn.
Step 3: Divide
Divide the cash from step 1 by the net burn from step 2. The result is months of runway.
Worked examples
Example 1: Simple case
Workday's example: $4.2 million of available cash and $350,000 of net monthly burn.
$4,200,000 ÷ $350,000 = 12 months
Example 2: Net burn from revenue and spending
Stripe's startup runway guide calculates net monthly burn as monthly expenses minus monthly revenue. With $800,000 in the bank, $90,000 of expenses and $35,000 of revenue:
- Net burn = $90,000 − $35,000 = $55,000
- Runway = $800,000 ÷ $55,000 = about 14.5 months
Example 3: A short runway
CFI's explainer uses $250,000 in the bank, $90,000 of monthly spending and $20,000 of cash sales. Net burn is $70,000, so runway is $250,000 ÷ $70,000, or about 3.6 months. That is a company that has to act almost immediately.
Gross versus net on the same company
Take the CFI company again. On gross burn alone, $250,000 ÷ $90,000 gives about 2.8 months. On net burn, 3.6 months. The gap is the revenue the company is counting on. FoundersCPA illustrates the same point: gross burn gives the shorter runway you would face if revenue dropped to zero. Showing both is a quick stress test.
An illustration for stock investors
Here is a hypothetical company (the numbers are invented to show the method). Its latest quarterly report shows $90 million in cash and equivalents. Over the last three months, its operating cash outflow plus capital spending came to $5.5 million, $7 million and $8.5 million.
- Average monthly net burn = ($5.5M + $7M + $8.5M) ÷ 3 = $7 million
- Runway = $90M ÷ $7M = about 12.9 months
The burn is climbing, though. If next month's burn is $8.5 million, the runway at that rate falls to about 10.6 months. Trend matters as much as the level.
When burn changes from month to month
Real burn is lumpy. Annual insurance premiums, delayed customer payments and one-off legal bills all distort a single month. Two fixes work well.
Use an average. Insaplan suggests dividing current cash by average monthly net cash burn. FoundersCPA recommends a trailing three-month average so runway does not swing with invoice calendars.
Adjust for known events. Workday lists timing gaps between paying expenses and collecting revenue as a common pitfall, and says one-time or irregular expenses can inflate burn temporarily and hide the underlying pattern. Stripe shows the effect: once it spreads an annual insurance cost across the year and allows for a summer revenue slowdown, its example runway drops from 14.5 months to 13.25 months.
A practical routine:
- List the last three to six months of net burn.
- Remove one-time items, such as a settlement, and note them separately.
- Average what is left.
- Add back scheduled costs you know are coming, such as an annual premium or tax payment.
- Calculate runway on the adjusted figure, and again on the worst recent month.
If the two answers are close, the number is sturdy. If they are far apart, the runway is a range, and you should talk about it as one.
Negative burn: when runway does not apply
Not every company has a runway problem. Allianz Trade explains that when net burn is positive you divide cash by it to get months, but when revenue exceeds expenses the cash balance grows and there is no countdown. For a profitable company, other questions matter more: how much cash the business generates and how efficiently it turns profit into cash. Our guide to free cash flow covers that side, and profitability versus cash flow explains why a company can report profit and still run short of cash.
Where investors find the inputs
For a public company you do not need a spreadsheet from management. Everything comes from the latest quarterly and annual reports.
- Cash: the balance sheet line for cash and cash equivalents. Add short-term investments only if they are easy to sell.
- Burn: the cash flow statement. Start with cash flow from operations, then subtract capital expenditures to see the cash the business consumed in total. Quarterly figures divided by three give a monthly rate.
- Debt due soon: the balance sheet and debt notes. A loan maturing in six months changes what "available" cash means.
- Working capital effects: payables and receivables can move cash without any change in the real business. If you see big swings, our piece on the cash conversion cycle and the negative working capital trend rules show how to separate timing from trouble.
If you want to dig into how operating results turn into cash, the EBITDA to free cash flow bridge is a useful companion to this calculation.
How to read the result
Investing.com says investors treat runway as a leading indicator of financial risk and dilution: companies with 12 months or less are more likely to announce stock offerings soon. For a shareholder, that means a short runway often leads to one of four outcomes:
- A stock or convertible offering, which dilutes existing owners.
- Debt financing, which adds interest costs and fixed obligations.
- Cost cuts, which can extend runway but may slow growth.
- A move to break-even, the best case, where burn shrinks toward zero.
A rough way to sort what you find:
| Runway | What it usually signals | What to check next |
|---|---|---|
| Under 6 months | Urgent: financing or cuts are likely soon | Debt maturities, going-concern language, recent offerings |
| 6 to 12 months | Pressure: management is probably raising money | Is burn falling or rising? Is there an open credit line? |
| 12 to 24 months | Workable if burn is stable | Path to break-even, milestones before cash runs low |
| Over 24 months, or no burn | Comfortable on this measure | Valuation, profitability, competitive position |
These bands are a rule of thumb for sorting, not a regulatory standard. Use them to decide where to look harder, not as a buy or sell signal.
What runway cannot tell you
The calculation is simple, so it is easy to over-trust. Investing.com lists the main limits: it is a snapshot based on current spending, it does not account for changes in revenue, expenses or one-time events, and it does not capture the quality of spending. Cash burned on high-return growth is very different from cash burned to prop up operations with no clear path forward.
So pair runway with other checks:
- Spending quality: is burn going into products and customers that are growing, or into overhead?
- Trajectory: is burn shrinking quarter after quarter?
- Valuation: a long runway does not make an overpriced stock a bargain. Our valuation metrics checklist is a fast way to test price against fundamentals.
- Balance sheet strength beyond cash: some value investors look for companies trading below their net current assets, which we cover in the net-net stock toolkit.
Runway beyond startups: personal and property investing
The same arithmetic works for individuals. A retiree can divide savings earmarked for spending by monthly net withdrawals to see how long a bucket lasts. A landlord can divide a reserve fund by monthly shortfall when rents do not cover costs. The principle is identical: cash on hand over net monthly outflow. If you invest in rental property, these rental property cash flow examples show how income and expenses net out for short-term rentals, which is the same net-burn thinking applied to a house.
Common mistakes
- Using revenue instead of cash collected. An invoice sent is not cash received. Burn is about cash.
- Including non-cash expenses. Depreciation and amortization reduce profit but do not leave the bank.
- Counting financing as revenue. Money raised is not an operating inflow. Strip it out of net burn, or you will make a burning company look healthy.
- Using one month. One strong or weak month misleads. Average at least three.
- Ignoring debts. Cash that is already owed is not runway.
- Assuming flat spending. A company that is hiring or scaling up will burn more next quarter than last.
What we think about runway
Runway is one of the fastest ways to see whether a business has time on its side, and it is also one of the easiest numbers to misread. A single ratio will not tell you whether a company is worth owning.
At Oracle Investments we start from reported company fundamentals: profitability, valuation and financial health, scored by rules, with every input visible. We built the app that way because we believe investors decide better when they can see exactly how a score is reached, rather than trusting a black box.
The value investors we learn from, Buffett, Munger and Lynch, all pushed the same discipline: understand the cash a business really generates and the balance sheet it stands on before you think about price. Runway fits that approach. It is a balance-sheet question answered with a cash-flow input, and it belongs next to profitability and valuation, not instead of them.
Our aim is to make that discipline possible in seconds, without building a spreadsheet for every company.
Matt
Put the numbers to work
Checking runway for one company is quick. Doing it across a watchlist, next to profitability and valuation, is where time disappears. Oracle Investments scores over 260 stocks on profitability, valuation and financial health, lets you compare companies side by side, and tracks your portfolio. The ratings are rule-based and grounded in reported fundamentals, with the scoring inputs shown, so you can see why a company ranks where it does.
If you want a faster way to screen for financial health before you open a single filing, see the Premium Annual plan in the Oracle Investments app on the Apple App Store.
FAQ
What is a good cash runway?
It depends on the company and the economy. Investing.com notes that companies with 12 months or less are more likely to announce stock offerings soon, so many investors treat 12 months as a watch line and 18 to 24 months as comfortable. A company with a clear path to break-even can safely hold a shorter runway than one with no such path.
What is the difference between burn rate and runway?
Burn rate is how much cash a company loses per month. Runway is how many months it can sustain that loss. Runway is simply cash divided by net burn, so a lower burn or a bigger cash pile both lengthen it.
Should I use gross burn or net burn?
Use net burn for the main runway figure, because it reflects the true pace at which cash declines. Calculate gross burn too as a stress test: it shows how long the cash would last if revenue stopped entirely.
How do I calculate runway when burn changes every month?
Divide current cash by the average net burn over the last three months or more, and remove one-time items. Then adjust for costs you know are coming, such as annual premiums. If recent months trend up, also calculate runway at the latest month's burn.
Does a profitable company have a cash runway?
If net burn is zero or negative, cash is growing and there is no countdown to calculate. In that case look at free cash flow, cash conversion and valuation instead.
Sources
- What Is Cash Runway? A Practical Guide for Investors, Investing.com
- How to Calculate Cash Burn, Workday
- Cash Runway: How to Calculate and Extend It, Capital One
- Cash Runway Explained: Formula, Examples and Uses, CFI
- How to Calculate Startup Runway, Stripe
- Burn Rate and Runway: How to Calculate Both, FoundersCPA
- Cash Runway: Key Metrics, Calculation, and Strategies, Allianz Trade
- Cash Runway: Formula and Calculator, Wall Street Prep
- Cash Runway KPI: Definition, Formula and How to Measure, Insaplan
- Sedona Rental Property Cash Flow Examples