What is a financial runway? Work out the year you can afford it

In a start-up, a runway is how many months the cash lasts. For a household the idea is the same, with two questions under it: how long will my money carry me, and how far am I from the thing I’m aiming at? That might be a home deposit, an investment property, a year off, or the day the pay cheque stops.

Most tools answer one of those at a time. A mortgage calculator doesn’t know about your super. A retirement calculator doesn’t know you plan to buy a house first. A runway is the answer to all of it on one timeline.

Why a year, not a number

“How much do I need?” has no useful single answer, because it depends on when. A deposit that is out of reach this year can be comfortable in four, once savings, pay rises and the loan balance have all moved. So a runway is a line through time: your net position in each year, and the year it crosses what the next step needs.

Australia’s financial year runs from 1 July to 30 June, and tax, super caps, and most government thresholds reset on that cycle. Working in financial years means the line follows the same calendar the rules do.

What goes into a runway

• What you have: savings, an offset account, shares, super, property, and what each is expected to earn.
• What you owe: the mortgage, a HELP debt, a car loan, and how each is repaid.
• What comes in and goes out: income, living costs, and the changes you can already see coming, such as a second child or a part-time year.
• The rules: income tax and the Medicare levy, super contribution caps, capital gains tax, stamp duty and land tax, and for later years the Age Pension’s means tests.

Why the rules matter as much as the figures

Two households with the same income and savings can have very different runways, because the rules bite differently. Stamp duty on a purchase is paid in the year you buy, from money you may not have counted on. Under today’s rules, selling an asset held for at least a year can halve the taxable part of the gain. Super contributions are taxed differently from money in a bank account, and can’t be reached until a condition of release is met. A projection that skips these is a rough guess dressed as a plan.

Our other posts take the main ones in turn: the upfront costs of buying a home, first home buyer stamp duty by state, land tax, super contribution caps, the capital gains tax discount, the Age Pension means tests and drawing a pension from super.

What a runway is not

It is a projection, not a prediction. It shows what happens if the figures you give it hold, such as a steady return, an unchanged wage, and the rules as they stand today. Change an assumption and the line moves; that is the point. Seeing how far it moves tells you which assumptions matter most to your household.

It is also not advice. A runway shows the consequences of your choices; the choices stay yours.

Working yours out

You can do the first version in a spreadsheet: a row per year, a column for each asset and debt, and a formula for each rule. It works until the rules start to interact, when selling a share adds a capital gain to your taxable income, which changes your income tax and Medicare levy, which changes what is left that year to save or put into super. That is where a tool that already holds the rules earns its keep.