Burn Rate & Runway Calculator
Calculate your startup's monthly burn rate and cash runway — how many months until you run out of money.
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How to use this calculator
Gross burn is total expenses. Net burn subtracts revenue. Runway is how many months of cash remain at the current net burn rate. If revenue exceeds expenses, the business is cash-flow positive.
- 1
Enter your current bank balance including all cash and cash equivalents.
- 2
Add your average monthly revenue for the last 3 months (use 0 for pre-revenue startups).
- 3
Enter total monthly expenses: payroll, rent, software, marketing, and all other costs.
- 4
If runway is under 6 months, start fundraising or cut costs immediately — the ideal trigger is 12+ months.
Frequently asked questions
How does the calculator work out net burn and runway?
This tool uses net burn = monthly expenses − monthly revenue, and runway in months = current cash ÷ net burn. With $500,000 in cash, $18,000 of revenue and $65,000 of expenses, net burn is $47,000 and runway is 10.6 months. The result assumes both monthly figures stay exactly as entered.
What does it show when revenue is at or above expenses?
If revenue is higher than expenses, the result reads cash flow positive, shows the monthly surplus, and reports no runway limit. If the two are exactly equal, it says net burn is $0 and the cash balance holds steady. With $30,000 of expenses against $40,000 of revenue the surplus line shows $10,000.00.
What is the “Cash runs out” date?
It is today’s date moved forward by the whole number of months in the runway, shown as a month and year. Because it starts from today, the same inputs give a later date next month. Runway above 1,200 months is shown as more than 100 years away instead of an invalid date.
What happens if the cash balance is zero?
The runway is 0.0 months whenever net burn is positive. Negative cash, revenue or expenses are treated as zero, so an overdraft cannot be entered as a negative balance and the tool will not show a negative runway.
What is the difference between the gross burn and net burn lines?
Gross burn is the monthly expenses you typed, before revenue. Net burn subtracts revenue. A company with $30,000 of expenses and no revenue has equal gross and net burn, and the $120,000 cash example gives exactly 4.0 months. The gross figure is displayed only when the business is burning cash.
Does revenue mean cash received?
The tool treats it as cash arriving each month. If invoices are paid late, revenue is lumpy or you bill annually, the monthly average you type can differ from what the bank sees in a given month, so the runway is only as good as that average.
Does it model growth, hiring or a fundraise?
No. Burn is held flat, so rising costs, falling revenue, seasonal swings, loan repayments, tax bills and new funding are not included. To test a scenario, change the expense or revenue input and compare the runway lines.
Burn rate and runway calculator: net burn, gross burn and months of cash
The two numbers behind runway
Runway is a division of cash by net burn, and net burn is one subtraction. That makes the result easy to check, but it also means every output depends on three inputs staying where you set them. The calculator never projects growth or hiring, so it answers one question: if nothing changed from today, how long would the money last.
| Output | How it is calculated | Shown when |
|---|---|---|
| Net burn rate | Expenses − revenue | Expenses exceed revenue |
| Gross burn rate | Expenses as entered | Expenses exceed revenue |
| Runway | Cash ÷ net burn, in months | Expenses exceed revenue |
| Cash runs out | Today + whole months of runway | Expenses exceed revenue |
| Monthly surplus | Revenue − expenses | Revenue exceeds expenses |
Three cases, run through the tool
The default inputs describe a company with $500,000 in the bank, $18,000 of monthly revenue and $65,000 of monthly expenses. The second case has no revenue, and the third sits exactly at break-even. The calculator produced each figure below from those inputs.
| Cash · revenue · expenses | Net burn | Runway |
|---|---|---|
| $500,000 · $18,000 · $65,000 | $47,000.00 | 10.6 months |
| $120,000 · $0 · $30,000 | $30,000.00 | 4.0 months |
| $120,000 · $30,000 · $30,000 | $0 (break-even) | Cash balance holds steady |
What a lower expense figure does
Runway is sensitive to the denominator. In the first case, taking monthly expenses from $65,000 to $55,000 would change net burn from $47,000 to $37,000, so it pays to test cuts and revenue changes one at a time. Use the tool to compare two versions of the same plan, rather than treating a single runway number as a prediction.
Choosing the monthly figures
Use an average of recent months rather than the best or worst month. Include everything that leaves the account each month: payroll, rent, software, taxes and loan payments. If a large annual bill is coming, spread it across twelve months before typing the expense figure. The same applies to annual revenue paid up front. Round numbers are fine, but keep the cash balance current, since an out-of-date balance shifts the runway by the same proportion as an error in burn would. If you hold cash in several accounts, add them together before entering the balance.
Limits to keep in mind
The output is a straight-line estimate. It does not know about a hiring plan, a price change, a customer who might leave or money you might raise, and it makes no recommendation about when to act. Recalculate whenever the bank balance or the monthly averages change, and keep the inputs from the same date so the cash balance and the monthly averages describe the same moment.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →