Cash runway at a glance
Enter Current cash balance, monthly revenue, and monthly expenses to get an estimated cash runway and a month-by-month projection. Optional growth rates change projected revenue and expenses from month 1 onward. The result also shows month-1 net burn, the assumptions, and the formulas used.
How the cash runway calculation works
The calculator simulates cash one month at a time. It detects depletion when ending cash falls to or below zero, so the ending balance may be negative after a monthly deduction.
Net burn (month m) = Expenses(m) − Revenue(m)Cash(m) = Cash(m−1) − Net burn(m)Cash runway (months) = first m where Cash(m) ≤ 0, interpolated
Revenue and expenses compound from their month-1 values: Revenue(m) = Revenue × (1 + revenue growth rate)^(m−1) and Expenses(m) = Expenses × (1 + expense growth rate)^(m−1). When net burn in the depletion month is positive, the runway is interpolated within that month using (m−1) + Cash(m−1) ÷ Net burn(m).
Inputs, assumptions, and validation
- Current cash balance, Monthly revenue (month 1), and Monthly expenses / burn (month 1) must be numbers of 0 or more.
- Growth-rate fields are optional. Blank values count as 0%; entered rates must be greater than -100.
- Use monthly, cash-based figures. Growth is constant and compounding, so the tool does not model seasonality or irregular changes.
- The currency choice is a display label only; it does not convert values or apply an exchange rate.
How to use the calculator
- Enter values in Current cash balance, Monthly revenue (month 1), and Monthly expenses / burn (month 1).
- Optionally enter Monthly revenue growth rate (optional) and Monthly expense growth rate (optional).
- Choose 6, 12, 24, 36, or 48 months in Months to show in projection table.
- Select Calculate runway.
- Use Copy result or Download result (.txt). These outputs contain only the selected displayed months.
How to read the result
Review Net burn, month 1 and Estimated cash runway. Net burn is negative when revenue exceeds expenses. The projection columns are Month, Revenue, Expenses, Net burn, and Ending cash.
The result identifies the first month when ending cash falls to or below zero. The depletion row is highlighted only when it falls within the selected table range and its starting cash is positive. A shorter table can therefore end before the estimated depletion month.
Limits and privacy
Runway detection simulates up to 600 months, or 50 years. This search is separate from the selected projection-table length. If cash is not depleted in that range, the calculator reports that runway exceeds the simulation range. It does not fetch bank balances, accounting data, or live financial records, and it does not model seasonality, one-time items, financing events, or irregular spending or revenue changes.
The calculator script uses the figures you enter locally and does not send those figures to a server. This describes the calculator calculation; it does not establish how other page features, such as analytics or the subscription form, handle data.
Frequently Asked Questions
How is cash runway calculated?
Cash runway is found by projecting your cash balance forward one month at a time, subtracting each month's net burn (expenses minus revenue), until ending cash falls to or below zero. The runway in months is interpolated to a fraction of the month in which the balance is depleted, rather than only using the whole-month count.
What if my revenue and expenses change over time?
You can enter an optional monthly revenue growth rate and monthly expense growth rate. Each month's revenue and expenses are compounded by that rate from month 1, so the projection reflects steadily growing or shrinking revenue and costs rather than assuming they stay flat.
Does this tool fetch my actual bank balance or accounting data?
No. It only calculates from the cash balance, revenue, expenses, and growth rates you type in. It does not connect to a bank, accounting system, or fetch live financial records. The calculator script uses those figures locally and does not send them to a server.
What does "exceeds the simulation range" mean?
The calculator simulates up to 600 months (50 years) looking for the point when ending cash falls to or below zero. If cash is not depleted within that range, the tool reports that runway exceeds the simulation range instead of an exact month.
Is this a substitute for financial or accounting advice?
No. This tool performs a transparent arithmetic simulation on the figures you provide. It is not financial, accounting, tax, or investment advice, and it does not account for seasonality, one-time items, financing events, or unplanned changes in spending or revenue.