FINBIZTOOLS
Runway Calculator
Calculate cash runway — how many months of cash remain — from your current cash balance and net monthly burn rate.
Private by design · Entries and logos stay in this browser. Nothing is saved automatically.
Changes the currency symbol and number format only. Amounts are not converted.
How to use the Runway Calculator
- Enter the current cash balance.
- Enter the net monthly burn rate (use the Burn Rate Calculator first if you don't already have this figure).
- Select Calculate to see the estimated runway in months.
Use the currency selector above the inputs to change the symbol. It changes the display only and does not convert amounts.
What is runway?
Runway is the number of months a business can continue operating at its current net burn rate before running out of cash, assuming no additional funding or change in spending.
It is a simple, widely used planning figure, most useful as a rough guide rather than a precise prediction, since burn rate rarely stays perfectly constant.
How the calculation works
Runway formula
Runway (months) = Cash balance ÷ Net monthly burn rate
- Cash balance is cash and cash equivalents currently available.
- Net monthly burn rate is monthly expenses minus monthly revenue — see the Burn Rate Calculator.
When net burn rate is zero or negative (the business is not depleting cash, or is cash-flow positive), runway is not a meaningful number of months, so the calculator explains this instead of showing an infinite value.
Runway calculation example
Cash balance of 600,000 with a net monthly burn rate of 50,000:
| Cash balance | 600000 |
|---|---|
| Net monthly burn rate | 50000 |
| Cash balance | 600000 |
|---|---|
| Net monthly burn rate | 50000 |
| Runway (months) | 12 |
The same cash balance of 600,000 with a burn rate of zero or a negative burn rate (cash-flow positive) has no finite runway figure to calculate; the calculator explains this rather than showing an invalid or infinite number. Amounts are shown without a currency symbol; the currency selector only changes the symbol and number format.
Assumptions and limitations
Assumptions
- Cash balance and net monthly burn rate are both current, single figures you supply for the same point in time.
- The calculation assumes burn rate stays constant going forward, a simplification of what is normally a changing figure.
Limitations and why results can differ
- Runway is only as reliable as the burn rate used; a rate based on one unusual month can over- or understate actual runway.
- It does not model planned future changes in spending or revenue, additional funding, or seasonal variation.
Frequently asked questions
How is runway calculated?
Runway in months is the current cash balance divided by the net monthly burn rate.
What happens if my burn rate is zero or negative?
Runway is not a meaningful number of months in that case, since cash is not being depleted (or is growing). The calculator explains this rather than showing an infinite or invalid figure.
Does runway account for planned future spending changes?
No. It assumes the entered burn rate stays constant. Recalculate with an updated burn rate as spending or revenue changes.
Where do I get my net monthly burn rate?
Use the Burn Rate Calculator, which computes net burn rate from monthly operating expenses and monthly revenue.
Methodology
Cash balance (0 to 1,000,000,000,000) and net monthly burn rate (−1,000,000,000,000 to 1,000,000,000,000, so a negative burn rate/cash-flow-positive month can be entered) are validated directly.
When burn rate is positive, runway (months) = cash balance ÷ burn rate. When burn rate is zero or negative, the calculator reports this is not applicable instead of an infinite value. The calculation runs in your browser and inputs are not sent to a server.
Last reviewed:
Disclaimer
Results are calculated estimates based on the figures you enter. They are not accounting, pricing, tax or legal advice. Verify important business and pricing decisions with your own records and a qualified professional. Read the full Disclaimer.
Explore this topic
This tool is part of SaaS and Startup Metrics.
A common order: measure recurring revenue and churn, compare customer value with acquisition cost, then check runway.
- MRR Calculator
- LTV:CAC Calculator
- Runway Calculator (this page)