Small-business finance
Cash runway
Estimate months until cash reaches a chosen reserve under constant burn.
Your inputs
Complete the fields for your selected method. Zero means intentionally zero, not unknown. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
(cash-reserve)/(monthly outflow-inflow).
Constant monthly flows. Cash at the reserve is exhausted for this purpose. Does not forecast future sales.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Available cash now (selected currency): Matching invoice, quote, statement, bookkeeping record or explicit budget amount for available cash now. Use the stated period and exclude amounts already counted in another field. Zero means intentionally excluded/not incurred, not unknown.
- Minimum cash reserve (selected currency): Matching invoice, quote, statement, bookkeeping record or explicit budget amount for minimum cash reserve. Use the stated period and exclude amounts already counted in another field. Zero means intentionally excluded/not incurred, not unknown.
- Monthly cash inflow (selected currency): Actual/expected MONTHLY cash receipts, not sales invoices.
- Monthly cash outflow (selected currency): Actual/expected MONTHLY cash payments, not accrual expense.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Monthly net burn is $4,000.00 for the illustrative inputs below.
Example inputs
- Available cash now: $30,000.00
- Minimum cash reserve: $6,000.00
- Monthly cash inflow: $5,000.00
- Monthly cash outflow: $9,000.00
- Monthly net burn
- $4,000.00
- Time until reserve
- 6.00 months
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Estimate months until cash reaches a chosen reserve under constant burn.
Keep inputs on the same scope and time basis. Calculations retain precision internally; displayed values generally round to two decimal places, with extra precision for very small values and whole-unit rounding where required. Economic comparisons describe your supplied assumptions and do not guarantee future results.
This tool provides business arithmetic. It does not approve engineering designs, establish legal or tax treatment, select equipment or certify safe operating conditions.