This Series A Runway Calculator estimates how many months a company can operate before its available cash is exhausted. It combines current cash, monthly revenue, monthly operating expenses, and an optional minimum cash reserve.
The result helps founders and finance teams time fundraising, hiring, and spending decisions. Because revenue and expenses can change quickly after a Series A round, treat the output as a planning snapshot and rerun it when forecasts change.
1. Enter cash
Use unrestricted cash currently available to fund operations.
2. Add monthly revenue
Enter expected cash collections, not booked revenue that has not been collected.
3. Add monthly expenses
Include payroll, vendors, rent, and other recurring cash outflows.
4. Set a reserve
Optionally protect a cash amount that should not be spent.
5. Read the runway
Use the estimated months and projected balance to plan financing milestones.
Runway is finite only when expenses exceed revenue. The model holds monthly revenue and expenses constant and excludes financing inflows, one-time costs, and working-capital timing changes.
Runway is the number of months the company can fund the current net cash burn before reaching the selected reserve.
A flat monthly model is useful for planning but should be supplemented with a detailed cash forecast.
Given
Calculation
Net burn = $1,300,000 - $900,000 = $400,000. Usable cash = $8,000,000 - $500,000 = $7,500,000. Runway = $7,500,000 / $400,000 = 18.75 months.
Result
Estimated runway = 18.8 months.
At the current run rate, the company reaches its reserve in a little under 19 months.
The calculator shows no projected depletion because the entered run rate is cash-flow positive. That does not account for future growth investments or one-time payments.
Usually no. Enter only cash that can legally and operationally be used for normal company expenses.
Update it at least monthly and whenever hiring, pricing, fundraising, or major spending assumptions change.
No. Add only cash already available. A prospective round should be modeled separately until it closes.
A reserve prevents the runway estimate from assuming every dollar can be spent. It can represent payroll protection, debt covenants, or an operating buffer.