What is this runway calculator?
A free, browser-based calculator that tells you how many months of runway you have left — how long your cash will last at your current burn rate. Enter your cash balance, monthly expenses, and monthly revenue, and it computes your net burn, your runway in months (and years + months), and roughly when your cash runs out. Everything runs locally in your browser, so your numbers are never uploaded.
How it is calculated
Runway is cash balance divided by monthly net burn. Net burn is your monthly expenses minus your monthly revenue — the actual cash leaving your account each month. When net burn is zero or negative (you are break-even or profitable), your cash is not shrinking, so runway is effectively unlimited.
- Net burn = monthly expenses − monthly revenue.
- Runway (months) = cash balance ÷ net burn (when net burn > 0).
- Gross burn ignores revenue; net burn subtracts it. Pre-revenue, the two are equal.
How to use it
- Enter your current cash balance.
- Enter your total monthly expenses (gross burn).
- Enter your monthly revenue (use 0 if pre-revenue).
- Read your net burn, runway, and cash-out timing on the right.
Common use cases
- Checking whether you have the 12–18 months of runway investors expect.
- Deciding when to start fundraising before cash gets tight.
- Seeing how a hire or cost cut changes your months of runway.