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Business cash buffer calculator
See how long your available cash covers essential costs. Compare a reserve target you choose, then test expected receipts separately.
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Check the cash you can use
Count cash already available for these costs. Keep unpaid invoices and money set aside for other obligations out of this reserve.
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Example: three months without new receipts
Your cash today
USD $9,000 available cash ÷ USD $3,000 essential monthly outgoings = 3 months of coverage without new receipts.
A chosen four-month target needs USD $12,000. That leaves a USD $3,000 shortfall against this target.
A separate receipts scenario
If USD $1,000 arrives each month, monthly net cash use falls to USD $2,000. The same reserve then covers 4.5 months under that assumption.
Your available cash is still USD $9,000. If receipts arrive late, this monthly average can miss a cash gap.
These are chosen examples. Your reserve target depends on your costs and circumstances; this tool does not choose it for you.
How to check your buffer
- Choose one currency.
- Enter available cash and essential costs.
- Choose your own target months.
- Compare, then save your assumptions.
The formulas and limits
Coverage = available cash ÷ essential monthly outgoings.
Target reserve = essential monthly outgoings × chosen target months.
Scenario coverage = available cash ÷ (monthly outgoings − expected monthly receipts).
Target cash rounds up to cents. Coverage rounds to two decimal places without reusing rounded values in other calculations.
Zero outgoings have no finite coverage result. If scenario receipts meet or exceed costs, cash does not deplete under that constant-flow assumption.
Costs and scenario receipts are spread evenly from now. This ignores within-month timing and gives no calendar cash-zero date. It does not calculate tax.
Check when cash actually arrives with the 13-week cash flow forecast. Move a receipt date to test a late payment before relying on that money.
This is a planning estimate, not financial, accounting, tax or legal advice. Business.gov.au’s cash-flow guide explains how to plan ongoing obligations.
Questions about your cash buffer
What is a healthy cash flow for a small business?
Check whether available cash covers obligations when they fall due. This calculator shows months of essential costs and your chosen target. A dated forecast helps you check payment timing. No single reserve amount suits every business.
Why can a profitable business run short of cash?
A client payment can arrive after your bills are due. Profit on a job does not mean that money has reached your bank. Compare the no-receipts result, then use the forecast to check dates.
What should I include in monthly costs?
Include cash this reserve must cover, such as rent and required owner drawings. Include debt payments where relevant. Keep money already reserved for other obligations separate and avoid counting the same obligation twice. Non-cash depreciation is excluded.
Should I count unpaid invoices as available cash?
No. Count money already available for these costs. You can test expected recurring receipts separately, but they remain uncertain. Use the 13-week forecast for individual invoice payment dates.
How many months of cash should I keep?
Choose a target based on your obligations and payment risks. Three months is the default worked example, not financial advice. The calculator shows the cash needed and any gap against the target you enter.
Does no depletion mean I can safely spend the reserve?
No. That result assumes expected receipts keep meeting costs evenly from now. Actual payment dates, unexpected bills or changing costs can still create a shortfall. A surplus here only compares your cash with your chosen target.
Reviewed 30 October 2026.
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