Preparing financially

How lenders actually calculate what you can borrow

Income shading, the expense benchmark, why credit limits (not balances) count, and the serviceability buffer applied on top of all three.

Income: not every dollar counts the same

Lenders commonly apply "shading" — discounting a percentage of income types they consider less reliable, such as overtime, bonuses, casual shifts, or rental income from an investment property — rather than counting them in full. Base salary is typically counted at 100%; more variable income types are often shaded, sometimes substantially, and the exact discount varies by lender.

Expenses: the benchmark vs. your actual spending

Lenders are required to assess your actual declared expenses, but commonly compare them against a standardised expense benchmark — the Household Expenditure Measure (HEM), developed by the Melbourne Institute of Applied Economics — and use whichever figure is higher as a floor, meaning an unusually frugal household may still be assessed against a higher benchmark figure. This is a real reason two households with identical income can be assessed differently.

Debts: limits, not balances

For credit cards and similar revolving credit, lenders commonly assess serviceability against the credit limit, not your current balance — a $20,000 limit card you rarely use can still reduce your borrowing capacity as though it were close to fully drawn. Closing or reducing limits on cards you don't need before applying is a genuine, actionable step (see existing-debt guide).

The buffer, applied on top of all of this

After shading income, applying the expense benchmark, and counting debt limits, lenders then assess your ability to repay at a rate at least 3 percentage points above the loan's actual rate (Australian Prudential Regulation Authority, verified 6 Oct 2026) — see the safe-budget guide for what this buffer is actually for.

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Practical checklist

Before estimating your own borrowing capacity

• List which parts of your income are base salary vs. variable (overtime, bonus, rental)
• Check the credit limit (not balance) on every card and BNPL account you hold
• Consider closing or reducing limits on cards you don't need before applying
• Treat any online borrowing-capacity estimate as a rough starting point, not a real assessment

Questions for a professional

• How is my variable income being treated in this assessment?
• What expense benchmark are you using, and how does it compare with my actual spending?
• Would reducing my credit card limits meaningfully change my borrowing capacity?

Official resources

• APRA: bank prudential standards

Sources and methodology

• Strengthening residential mortgage lending assessments | APRA — Australian Prudential Regulation Authority (retrieved 6 Oct 2026). Licence: CC BY 4.0
• Tax rates - Australian residents | Australian Taxation Office — Australian Taxation Office (retrieved 23 Oct 2026). Licence: ATO copyright notice — free reproduction, non-endorsement condition only

Figures on this page are drawn from Delora's local knowledge graph, refreshed from these primary sources and checked for changes on a regular schedule. If a figure here looks out of date, the official source above is always the authority — please let us know.