Runway tells management and investors how long the business can operate before it needs new funding or a change in course. Enter cash, monthly inflows and outflows, and growth assumptions to project burn and the cash-out month.
How it works
Estimate how long cash will last at current and projected burn rates, and when the balance will run out.
Gross burn = Monthly cash outflows
Net burn = Outflows − Inflows
Runway = Cash ÷ Net burn (current)
Projected runway: month-by-month balance with inflow and outflow growth until cash turns negativeCommon uses
- Startup and growth-company planning
- Fundraising timing and board updates
- Turnaround and liquidity management
Worked example
The calculator above opens with this example. Change any input to see the results update instantly, or select Reset to return to these figures.
| Current cash balance | $1,850,000 |
| Monthly cash inflows | $145,000 |
| Monthly cash outflows | $312,000 |
| Monthly inflow growth | 3% |
| Monthly outflow growth | 1% |
| First projected month | 2026-11 |
| Runway (with growth) | 11.7 months |
| Net burn (current) | $167,000 |
| Gross burn | $312,000 |
| Runway at current burn | 11.1 months |
| Projected cash-out month | Oct 2027 |
Common guidance is to begin raising capital or cutting costs with at least 9–12 months of runway remaining.
Interpreting the results
- Use cash figures, not accrual revenue and expense; collections lag billings.
- Model a downside case with slower inflow growth to see how quickly runway compresses.
Frequently asked questions
What is the difference between gross burn and net burn?
Gross burn is total monthly cash outflow. Net burn is outflows minus inflows — the actual monthly reduction in cash — and is the figure used to calculate runway.
How much runway should a company maintain?
Many venture-backed companies aim for 18 to 24 months of runway after a financing, and begin raising when roughly 9 to 12 months remain. Mature businesses with uncertain cash flow often set a minimum cash floor instead.
Why include growth rates in the projection?
Inflows and outflows rarely stay flat. Modeling growth in each shows whether revenue is closing the gap with spending fast enough to extend runway or reach cash-flow breakeven.
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