Business
Cash Runway Forecast Calculator
Project cash from opening balance, revenue, gross margin, payroll, operating expense, debt service, growth, forecast months, and a minimum reserve.
Opening monthly gross profit-
Monthly payroll, operating expense, and debt service-
Opening monthly net cash flow-
Opening monthly cash burn-
Simple runway at opening burn-
Revenue needed for monthly cash break-even-
Gross profit through forecast-
Fixed cash outflow through forecast-
Modeled cash at forecast end-
Ending cash above minimum reserve-
Final-month revenue-
Decision view
Cash balance curve with reserve risk band
Cash balance curve with reserve risk bandCash is carried month by month through the growing-revenue forecast and compared with the minimum-reserve threshold.
Exact scenario comparisonMonthly revenue growth (%) changes while all other entered assumptions remain constant.
| Monthly revenue growth (%) | Opening monthly gross profit | Monthly payroll, operating expense, and debt service | Opening monthly net cash flow | Opening monthly cash burn | Simple runway at opening burn | Revenue needed for monthly cash break-even | Gross profit through forecast | Fixed cash outflow through forecast | Modeled cash at forecast end | Ending cash above minimum reserve | Final-month revenue |
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Period-by-period detail
Monthly revenue, burn, and cash runway forecast
How to use Cash Runway Forecast Calculator
- Enter cleared opening cash and a reserve that should not be spent.
- Enter revenue, margin, payroll, operating expense, and debt service on the same monthly basis.
- Set a defensible growth path and compare the simple runway with the full cash curve.
Calculator guide
Understanding Cash Runway Forecast Calculator
Cash runway depends on both the opening burn rate and the full monthly revenue-growth path. This calculator keeps the simple opening-burn reference separate from the forecast ending balance.
Detailed calculation process
Reconcile opening burn with a growing-revenue cash forecast
The default uses $180,000 opening cash, $45,000 monthly revenue, 70% gross margin, $40,000 combined monthly outflow, 3% monthly revenue growth, 18 months, and a $25,000 reserve.
General formula: GP_0 = R_0 * m / 100F = Payroll + Opex + DebtNCF_0 = GP_0 - FBurn_0 = max(-NCF_0, 0)Runway = max(Cash_0 - Reserve, 0) / max(Burn_0, epsilon)R_BE = F / max(m / 100, epsilon)T = ((1 + g / 100)^n - 1) / (g / 100)GP_H = R_0 * T * m / 100F_H = F * nCash_H = Cash_0 + GP_H - F_HH = Cash_H - Reserve The simple runway freezes the opening burn and is only a reference. The full forecast instead sums every growing monthly revenue amount, applies gross margin, subtracts fixed cash outflow for every month, and then compares ending cash with the reserve.
What each symbol means
Worked substitution with the default inputs
The default simple opening-burn runway is 18.2353 months, but the full growing-revenue forecast ends with $197,554.71 cash and $172,554.71 above reserve.
Purpose-built visual
Cash balance curve with reserve risk band
A live area curve carries cash month by month and highlights the reserve threshold, unsafe zone, and ending balance.
Worked situations
Practical examples
- The default opening gross profit is $31,500 against $40,000 of monthly cash outflow, creating an opening burn of $8,500.
- The simple 18.2353-month runway freezes that burn, while the 3% revenue-growth path turns cumulative operations positive and ends at $197,554.71.
Better inputs
Useful tips
- Normalize monthly burn by separating recurring operations from one-time purchases, financing, and owner distributions.
- Enter cash that is actually available for operations rather than including restricted or already-committed balances.
- Run hiring, revenue-delay, and cost-reduction cases independently so the runway response to each decision remains visible.
Before relying on the result
Limitations and common mistakes
- Revenue collection timing, churn, hiring steps, taxes, financing, capital spending, and one-time costs are not modeled.
- Gross margin and fixed monthly outflow stay constant throughout the forecast.
- A positive modeled ending balance does not replace a week-by-week treasury forecast or financing plan.
Reference
Key terms
- Opening burn
- The amount by which opening monthly fixed outflow exceeds opening gross profit.
- Simple runway
- Spendable opening cash divided by opening burn, with no growth or cost change.
- Reserve headroom
- Forecast ending cash minus the protected minimum reserve.
Important note
Use a weekly treasury forecast when payroll dates, customer collections, taxes, debt payments, or financing events can create intra-month cash shortfalls.
Frequently asked questions
Why can simple runway and ending cash tell different stories?
Simple runway freezes the opening burn, while the full forecast includes every month's entered revenue growth.
What happens when opening burn is zero?
The simple runway is not economically limiting; use the full forecast to test later-month cash.
Should restricted cash be included?
No. Enter only cash available for the modeled operating purpose or protect it through the reserve.
Is revenue the same as cash collected?
Not necessarily. Adjust the inputs or use a timing model when collection delays are material.