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Burn Rate and Runway Calculator

Find out how many months of runway you have left. Enter your cash, burn and revenue to see gross burn, net burn and the month your cash runs out, accounting for revenue growth.

Your numbers

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Runway
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Gross burn / mo
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Net burn / mo
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Static runway no growth
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Cash-out point
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How runway and burn are calculated

Gross burn is your total monthly cash out (all expenses). Net burn is what you actually lose each month after revenue: expenses − revenue. Your runway is how long the cash lasts: in the simplest case, cash ÷ net burn.

This calculator goes a step further and grows your revenue month over month, so as revenue rises your net burn shrinks and your runway stretches, which is why the dynamic runway is usually longer than the static cash ÷ burn figure. If revenue overtakes expenses before the cash runs out, you reach cash-flow break-even and runway is effectively unlimited.

Most investors want to see 18 to 24 months of runway at a raise, because fundraising takes time and you need enough to hit the milestones that justify the next round. Under six months is a red flag, see cash flow forecasting and use of funds for what to do about it.

Worked example: $500K in the bank, $50K net burn

The static formula says this company has 10 months left; once revenue grows 8% a month, it never runs out of cash.

Default inputs of the calculator above. Change any input to run your own numbers.
ItemValue
Cash in the bank$500,000
Monthly expenses (gross burn)$90,000
Monthly revenue$40,000
Monthly revenue growth8%
Net burn, month 1 ($90,000 - $40,000)$50,000
Static runway ($500,000 ÷ $50,000)10.0 months
Revenue passes expensesaround month 11
Lowest cash balance (chart)$175,819
Runway with growth∞ (cash-flow break-even before cash runs out)

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Frequently asked questions

How do you calculate burn rate?
Gross burn is your total monthly cash out. Net burn is monthly expenses minus monthly revenue, the cash you actually lose each month. With the defaults above, $90,000 of expenses and $40,000 of revenue give a $50,000 net burn. More on both in cash burn rate explained.
What is the burn rate formula for runway?
Runway = cash in the bank ÷ net burn. $500,000 ÷ $50,000 = 10 months. That static figure assumes revenue stays flat; if revenue grows, net burn shrinks each month and the real runway is longer, which is what the month-by-month simulation above shows.
What is the difference between gross burn and net burn?
Gross burn counts every dollar going out; net burn subtracts the revenue coming in. Runway is based on net burn, while gross burn shows how much you could cut. See gross vs net burn.
How many months of runway should a startup have?
Most investors want to see 18 to 24 months of runway at a raise, because fundraising takes time. Under six months is a red flag: start a raise or cut burn.
How do I calculate runway in Excel?
For the static version, use =cash/(expenses-revenue). For runway with growth, make one row per month: revenue = last month × (1 + growth), cash = last month cash - (expenses - revenue). Runway is the first month where cash drops to zero or below.
What does default alive mean?
Paul Graham's test: at your current growth and spending, do you reach profitability before the cash runs out? If yes, you are default alive. With the defaults above, revenue passes expenses around month 11, so this company is. Read more in the burn rate and cash runway guide.

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Adlega. "Burn Rate and Runway Calculator for Startups." Updated October 22, 2026. https://adlega.com/blog/tools/runway/

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<a href="https://adlega.com/blog/tools/runway/">Burn Rate and Runway Calculator for Startups</a> (Adlega, updated October 22, 2026)

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