How to calculate cash runway
Start with the cash you have now, the revenue you expect in month 1, and the expenses you expect in month 1. The Cash Runway Calculator projects the balance month by month, then shows the formula, assumptions, and ending cash used for the estimate.
- Enter values in Current cash balance, Monthly revenue (month 1), and Monthly expenses / burn (month 1).
- Enter Monthly revenue growth rate (optional) and Monthly expense growth rate (optional), or leave either field blank for 0% growth.
- 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) to take the displayed calculation into another document.
Calculate cash runway from monthly cash flow
For each month, the calculator subtracts revenue from expenses to get net burn. It then subtracts net burn from the previous cash balance and records the first month whose ending cash is at or below zero. When net burn is positive, the runway can include part of that month.
Current cash balance: $500,000
Monthly revenue (month 1): $20,000
Monthly expenses / burn (month 1): $80,000
Net burn, month 1: $60,000
Estimated cash runway: 8.33 monthsThe formulas are Net burn (month m) = Expenses(m) − Revenue(m) and Cash(m) = Cash(m−1) − Net burn(m). In this example, cash runs out during month 9, so the result is 8.33 months.
What monthly growth rates change
Monthly revenue growth rate (optional) and Monthly expense growth rate (optional) apply from month 1 and compound each month. A blank field counts as 0%. You can enter a negative rate, but each rate must be greater than -100.
Monthly revenue growth rate (optional): 3
Revenue, month 1: $20,000
Revenue, month 2: $20,600
Monthly expense growth rate (optional): 1
Expenses, month 1: $80,000
Expenses, month 2: $80,800The projection keeps applying those rates each month. It does not include seasonality, one-time items, financing events, or irregular changes in revenue or expenses.
What the cash runway projection shows
Months to show in projection table controls how many rows appear: 6, 12, 24, 36, or 48. The runway search can still continue for up to 600 months. The result shows Net burn, month 1, Estimated cash runway, the first month cash falls to or below the selected currency's 0, an assumptions table, and five projection columns.
Currency symbol changes the amount label. Copy result and Download result (.txt) include the selected projection months and the calculation details.
Cash runway inputs and data handling
Current cash balance, Monthly revenue (month 1), and Monthly expenses / burn (month 1) must be numbers of 0 or more. The optional growth fields accept a number greater than -100, or a blank value for 0%. The script uses your figures in the browser and does not fetch or post them to a server. If cash never reaches zero during the 600-month search, the result says the runway exceeds the simulation range.
How to use the cash runway result
- Enter the company balance, expected first-month revenue, and operating expenses to estimate how long the current cash covers the plan.
- Add growth assumptions and copy the projection into a planning note.
- Compare flat and changing-growth scenarios in the Ending cash column.
When another business calculator fits
The Business Calculators category covers pricing, profitability, marketing, SaaS, and inventory. Use the Burn Rate Calculator for gross burn and net burn with cash runway. Use the SaaS Metrics Calculator for cash runway alongside MRR, ARR, CAC, LTV, churn, and Rule of 40. Use the ARR Calculator for recurring revenue annualization.
Frequently asked questions
How do I calculate cash runway in months?
Cash runway is calculated by projecting ending cash month by month until it reaches zero or below. Positive net burn allows interpolation within the depletion month.
What happens when revenue covers expenses?
When revenue covers or exceeds expenses and cash never depletes during the simulation, the result says the runway is not applicable. If later growth causes depletion, it reports that month.
Can I show a 24-month cash runway projection?
Yes. Select 24 months in Months to show in projection table, then select Calculate runway. The runway search can still check up to 600 months.
Does the Cash Runway Calculator use live financial data?
No. It calculates from the values you enter for cash, revenue, expenses, and growth rates. The calculator script does not fetch bank or accounting records and does not post those figures to a server.