What is my burn rate?
Type the cash going out and coming in each month, or the cash balance at two dates. The burn rate calculator shows the monthly cash burn and the runway, how many months the cash will last.
- Net burn per month
- $30,000.00
The net cash burn is $30,000.00 a month.
- Gross burn per month
- $55,000.00
- Runway
- 20
Net burn per month: $30,000.00. The net cash burn is $30,000.00 a month.
The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use
How to calculate
Works out a company’s monthly cash burn (gross and net) from its cash flows or from two cash balances, and the runway: how many months the cash lasts at that rate.
Example with the default inputs (Work it out from Monthly cash flows, Cash spent per month $55,000.00, Cash received per month $25,000.00, Cash on hand $600,000.00): The net cash burn is $30,000.00 a month.
Method: From cash flows: gross burn = cash spent per month; net burn = cash spent − cash received per month; runway = cash on hand ÷ net burn. From balances: net burn = (cash at the start − cash at the end) ÷ months; runway = cash at the end ÷ net burn.
- The monthly burn stays the same in the months ahead; runway is in months of that burn.
- Cash only: what is billed but not yet paid, and non-cash costs such as depreciation, are left out.
- Arithmetic is exact on the typed decimals; money shows to the cent and the runway to 1 decimal, halves rounded up.
Worked examples
Each example is checked against the calculator on every build.
- Work it out from Monthly cash flows, Cash spent per month $6,000.00, Cash received per month $0.00, Cash on hand $36,000.00 gives Net burn per month $6,000.00, Gross burn per month $6,000.00, Runway 6.Source: Arizona State University, Edson E+I Institute, Startup Financial Metrics Every Founder Should Track (2026-08-06): $36,000 in the bank, losing $6,000 a month, is 6 months of runway; at $4,000 a month, 9 months, https://entrepreneurship.asu.edu/blog/2026/08/06/startup-financial-metrics-every-founder-should-track/
- Work it out from Monthly cash flows, Cash spent per month $4,000.00, Cash on hand $36,000.00 gives Net burn per month $4,000.00, Runway 9.Source: Arizona State University, Edson E+I Institute, Startup Financial Metrics Every Founder Should Track (2026-08-06): $36,000 in the bank, losing $6,000 a month, is 6 months of runway; at $4,000 a month, 9 months, https://entrepreneurship.asu.edu/blog/2026/08/06/startup-financial-metrics-every-founder-should-track/: cutting the monthly loss to $4,000 stretches the runway to 9 months
- Work it out from Two cash balances, Cash at the start $900,000.00, Cash at the end $600,000.00, Months between 3 gives Net burn per month $100,000.00, Runway 6.Source: U.S. Securities and Exchange Commission, Office of the Advocate for Small Business Capital Formation, Glossary (burn rate: the rate at which a company spends its cash over time, frequently discussed as a monthly rate), https://www.sec.gov/resources-small-businesses/glossary
- Work it out from Monthly cash flows, Cash spent per month $55,000.00, Cash received per month $25,000.00, Cash on hand $600,000.00 gives Gross burn per month $55,000.00, Net burn per month $30,000.00, Runway 20.Source: U.S. Securities and Exchange Commission, Office of the Advocate for Small Business Capital Formation, Glossary (burn rate: the rate at which a company spends its cash over time, frequently discussed as a monthly rate), https://www.sec.gov/resources-small-businesses/glossary
How it works
From monthly cash flows:
- Gross burn per month = cash spent per month.
- Net burn per month = cash spent − cash received per month (an empty cash received box counts as $0).
- Runway = cash on hand ÷ net burn, in months.
From two cash balances:
- Net burn per month = (cash at the start − cash at the end) ÷ months between.
- Runway = cash at the end ÷ net burn, in months.
The runway shows only when the net burn is more than $0. A net burn below $0 means cash is growing by that much a month. Gross burn shows only when working from cash flows.
Rules:
- Every amount is $0 to $1,000,000,000,000. Months between are 0.01 to 1,200.
- A result too large to show as a number (a runway over about 1.8 × 10³⁰⁸ months, from a burn typed hundreds of decimal places below a cent) or not $0 but too small to show (under about 2.5 × 10⁻³²⁴) gives no answer: "A result is too large or too small to show as a number."
- The arithmetic is exact on the decimals you type. Money shows to the cent and the runway to at most 1 decimal (a trailing zero dropped), with halves rounded up (away from zero), from the exact value.
Assumptions
- The burn stays the same in the months ahead.
- Cash only: amounts billed but not yet paid, and non-cash costs such as depreciation, are not part of the burn.
Worked examples by hand
Arizona State’s example. Cash spent $6,000 a month, nothing coming in, $36,000 in the bank: gross and net burn $6,000; runway = 36,000 ÷ 6,000 = 6 months. At a $4,000 loss: runway = 36,000 ÷ 4,000 = 9 months.
From cash flows. $55,000 out and $25,000 in a month, $600,000 of cash: gross burn $55,000; net burn = 55,000 − 25,000 = $30,000; runway = 600,000 ÷ 30,000 = 20 months.
From two balances. $900,000 at the start, $600,000 three months later: net burn = (900,000 − 600,000) ÷ 3 = $100,000 a month; runway = 600,000 ÷ 100,000 = 6 months.
Other questions people ask
What is a burn rate?
The burn rate is how fast a company spends its cash, usually per month. Startups that are not yet profitable watch it closely, because it decides how long they can keep going before they need more money.
How do I calculate the burn rate?
Take the cash spent in a month and subtract the cash received. A company that spends $55,000 a month and takes in $25,000 burns $30,000 a month. Or take the cash balance at two dates: $900,000 falling to $600,000 over 3 months is (900,000 − 600,000) ÷ 3 = $100,000 a month.
What is the difference between gross and net burn?
Gross burn is all the cash spent in a month. Net burn takes off the cash coming in, so it is the amount the cash balance actually falls each month. Runway uses the net burn.
How do I calculate the runway?
Divide the cash on hand by the monthly net burn. $36,000 in the bank with a $6,000 monthly loss lasts 36,000 ÷ 6,000 = 6 months; cut the loss to $4,000 and it lasts 9 months.
What if cash is going up?
Then the net burn is below $0 and there is no runway to show: the cash balance grows at that rate. The page leaves the runway out until cash is falling.
How much runway should a startup have?
It depends on the company’s plan and on how long it takes to raise more money or reach profit. Raising money can take months, so plan the next round well before the runway ends.