Monthly Burn Rate Calculator
Measure gross and net monthly burn from the cash you spent over a period, then convert your balance into months of runway.
How it works
Net burn = (start cash − end cash) ÷ months · Gross burn = (cash used + revenue) ÷ months
Burn rate is how fast a company spends its cash reserves each month. Net burn is the actual monthly drop in your bank balance, while gross burn adds revenue back to show total monthly spending regardless of income. Measuring it over several months smooths out one-off swings like an annual insurance payment, giving a truer run rate than any single month.
Worked example
A startup holds $500,000 at the start of a quarter and $380,000 at the end, having earned $30,000 of revenue. Cash used is $120,000 over 3 months, so net burn is $40,000 a month. Adding revenue, gross burn is (120,000 + 30,000) ÷ 3 = $50,000 a month.
Frequently asked questions
Gross burn or net burn — which should I track?
Track both. Net burn tells you how long your cash lasts; gross burn tells you your true cost base, which matters if revenue is volatile or could disappear. Runway is always based on net burn.
Why measure burn over several months?
A single month can be distorted by lumpy payments — a quarterly tax bill, an annual software renewal. Averaging over a quarter or more gives a run rate that better predicts the future.
Can burn rate be negative?
If you end the period with more cash than you started, your net burn is negative — meaning the business is cash-flow positive and building reserves rather than depleting them.
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Educational estimate, not financial advice.