Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Runway at flat revenue (months)
8.9
Runway with growth (months)
12
Net monthly burn
$47,000
Gross monthly burn
$78,000
Revenue needed to break even
$78,000
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How to use this
- 1Enter cash in bank ($).
- 2Enter monthly expenses ($).
- 3Enter monthly revenue ($).
- 4Enter monthly revenue growth (%).
- 5Read your runway at flat revenue (months) on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Net burn is what actually drains the bank account each month. Under six months of runway is the point where fundraising stops being optional and starts being urgent.
Worked example
Using the values the calculator loads with:
Inputs
- Cash in bank: 420000 $
- Monthly expenses: 78000 $
- Monthly revenue: 31000 $
- Monthly revenue growth: 8 %
Results
- Runway at flat revenue (months): 8.9
- Runway with growth (months): 12
- Net monthly burn: $47,000.00
- Gross monthly burn: $78,000.00
- Revenue needed to break even: $78,000.00
What each field means
Inputs
- Cash in bank ($)
- The cash in bank used in the calculation, measured in $. Starts at 420000 $ so you have a working example on load.
- Monthly expenses ($)
- The monthly expenses used in the calculation, measured in $. Starts at 78000 $ so you have a working example on load.
- Monthly revenue ($)
- The monthly revenue used in the calculation, measured in $. Starts at 31000 $ so you have a working example on load.
- Monthly revenue growth (%)
- The monthly revenue growth used in the calculation, measured in %. Starts at 8 % so you have a working example on load. Accepted range: -50–100 %.
Results
- Runway at flat revenue (months)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Runway with growth (months)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net monthly burn
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Gross monthly burn
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Revenue needed to break even
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the burn rate and runway calculator work?
Net burn is what actually drains the bank account each month. Under six months of runway is the point where fundraising stops being optional and starts being urgent. The underlying maths is: Net burn = Expenses − Revenue. Runway = Cash ÷ Net burn.
What do I need to enter?
4 values: cash in bank, monthly expenses, monthly revenue, and monthly revenue growth. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the runway at flat revenue (months) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Burn Rate and Runway Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/burn-rate
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/burn-rate" target="_blank" rel="noopener">Burn Rate and Runway Calculator — RevenueLab</a> (2026).</p>
Source: [Burn Rate and Runway Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/burn-rate) (2026).