This calculator estimates how many months a pre-seed company can operate before available cash is exhausted. It subtracts monthly cash revenue from monthly cash expenses and optionally reserves part of the cash balance as an untouchable minimum.
Runway is a planning indicator rather than a promise. It helps founders time hiring, cost reductions, revenue milestones, and fundraising before the cash position becomes urgent.
1. Enter current cash
Use unrestricted cash available to fund operations.
2. Enter monthly expenses
Use expected cash outflows, including payroll, vendors, rent, and other operating payments.
3. Enter monthly cash revenue
Use cash expected to be collected during a typical month.
4. Set a minimum reserve
Exclude cash that should remain untouched for wind-down, obligations, or contingency.
5. Review runway
Use the result as a trigger for milestone planning and scenario testing.
Monthly net burn = Monthly cash expenses − Monthly cash revenue
Usable cash = Cash balance − Minimum reserve
Runway (months) = Usable cash ÷ Monthly net burn
If revenue equals or exceeds expenses, the model reports no finite runway because cash is not declining under the entered assumptions.
The result estimates the number of months until usable cash reaches the selected reserve level.
It assumes constant monthly cash flow and excludes one-time payments unless included in monthly expenses.
Given: $500,000 cash, $90,000 monthly expenses, $25,000 monthly cash revenue, and a $50,000 reserve.
Calculation: Net burn = $90,000 − $25,000 = $65,000. Usable cash = $500,000 − $50,000 = $450,000. Runway = $450,000 ÷ $65,000 = 6.92 months.
Result: The company has about 6.9 months of runway before reaching the reserve.
Only include amounts already collected unless collection timing is highly reliable and explicitly modeled. Runway is a cash metric.
Use a monthly cash forecast for greater accuracy. This calculator is best for a stable average or quick scenario.
A reserve prevents the estimate from assuming every dollar can be spent. It can cover wind-down costs, deposits, taxes, or contingency needs.
Not necessarily. Fundraising can take months, and investors may expect progress before cash becomes scarce.
Runway starts with available cash and estimates time remaining. Funding need starts with a target time horizon and estimates additional capital required.