Guide
How to Calculate Cash Flow Runway
Cashflow runway tells you how long the business can keep operating before cash runs too low if current conditions continue. It is one of the simplest ways to make pressure visible before it becomes a crisis.
In this guide
- Runway starts with cash reserves and net monthly burn.
- Revenue reduces burn, but only if it is arriving consistently.
- Late invoices and weak margins can shorten runway faster than expected.
Last updated
27 April 2026
Category
Pricing & Profit
Use with
3 related calculators
Guide
What cashflow runway actually measures
Runway estimates how long the business can keep operating before available cash is exhausted if the current revenue and expense pattern continues.
It is not a forecast of guaranteed survival. It is a decision tool that makes the current cash position easier to interpret while there is still time to act.
Start with net monthly burn
The key input is not total expenses alone. It is the net amount of cash the business is losing each month after monthly revenue is considered.
If monthly revenue is lower than monthly expenses, the business is burning cash. If revenue matches or exceeds expenses, the runway logic changes because the business is no longer consuming reserves at the same rate.
Simple runway formula
- Net monthly burn = average monthly expenses - average monthly revenue
- Runway in months = current cash reserves / net monthly burn
Use realistic revenue assumptions
Runway can look healthier than it really is if the revenue number assumes every invoice will be paid on time or every lead will convert as hoped.
If collections are slow or sales are inconsistent, it is safer to use a conservative revenue number rather than the best month you have seen recently.
Treat warning states seriously
If burn is close to zero, the business may be around break-even and the runway becomes less urgent, but that does not necessarily mean cash pressure has disappeared.
If burn is negative or zero because revenue currently covers expenses, the business is not consuming runway at the same pace. Even so, it is still worth checking margin, debtor speed, and fixed-cost exposure in case conditions change.
Use runway alongside the other pressure indicators
Runway becomes much more useful when you read it next to late invoices, break-even pressure, and whether pricing is leaving enough margin. If those areas are weak, the runway can shorten quickly.
That is why a runway number should usually trigger follow-up questions, not end the analysis.
Worked example
See it in a realistic business scenario
Use the example below as a quick sense check before you apply the same logic to your own pricing, payroll, quoting, or tax workflow.
Worked example
Worked example: estimating months of runway
A business has $90,000 in cash reserves, monthly expenses of $35,000, and monthly revenue of $20,000.
- Current cash reserves: $90,000
- Average monthly expenses: $35,000
- Average monthly revenue: $20,000
Calculation steps
- Net monthly burn = $35,000 - $20,000 = $15,000.
- Runway = $90,000 / $15,000 = 6 months.
On those assumptions, the business has about 6 months of runway. That gives the owner a clearer time window for pricing changes, cost cuts, collections, or revenue recovery actions.
Important note
Use the guide as a practical reference, not as advice
This page is designed to support better commercial decisions, but it should not be treated as a substitute for professional advice.
Important note
BizTools.au is designed to make business numbers easier to check, but calculator outputs still need judgment and real-world context.
- Calculator results are general estimates only and depend on the figures entered.
- Examples and summaries are provided for general information, not legal, tax, accounting, payroll, or financial advice.
- Before relying on a result for a real decision, check your assumptions and get qualified advice where needed.
Related tools
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These linked tools help you turn the ideas in the guide into a faster number check or a cleaner pricing decision.
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