Home Loan Borrowing Capacity: Income, Costs and Commitments

Home loan borrowing capacity is not a simple salary multiplier. A lender is trying to assess whether repayments remain manageable after living costs and other commitments, while you need to decide whether the resulting budget leaves room for the life you expect to lead.

Quick answer

Home loan borrowing capacity depends on verified income, living costs, existing commitments, loan terms and lender policy. A deposit alone does not establish affordability. Lenders assess repayment resilience as well as today’s instalment, while your own budget should allow for ownership costs and future changes. Treat online estimates as planning tools, not approval.

Home loan borrowing capacity has several limits

Think of the purchase as three connected checks. First, can your income support the proposed repayments under the lender’s assessment? Second, do the deposit and property valuation support the required loan? Third, does your own household budget remain workable after all ownership costs?

Passing one check does not automatically pass the others. A large deposit does not replace income. A strong salary does not remove valuation requirements. An approved loan does not decide how much financial flexibility you personally want to retain.

The aim is to understand which constraint matters in your circumstances. That is more useful than repeatedly adjusting a calculator until it displays the property price you hoped for.

Prepare income information the lender can assess

Separate regular salary from overtime, bonuses, commissions, investment income and other sources. Record the period each figure covers and whether it is before or after tax. A common calculator mistake is mixing annual gross income with monthly net income in the wrong field.

Ask how the lender treats variable earnings and what documents it needs. Do not assume every dollar received in an unusually strong month will be accepted as a stable ongoing amount. Conversely, do not omit a legitimate income source simply because you are unsure how it will be assessed.

For self-employed applicants, business revenue is not the same as personal income available for mortgage repayments. Our self-employed home-loan documents guide explains the records to organise before discussing a loan.

Build an honest expense picture

Use recent records and allow for annual or irregular bills. Convert expenses consistently to the period requested by the lender. Include costs that are easy to overlook when thinking only about weekly groceries, such as insurance, education, transport, childcare and health expenses.

Separate genuine changes from temporary cuts made to make a calculator look better. If a cost will end, document why and when. If a new cost is expected after purchase, include it in your own planning even if it has not appeared on a bank statement yet.

Do not understate dependants or commitments. The assessment is not a competition to produce the largest result; inaccurate inputs can undermine both approval and the usefulness of your personal budget.

List debts and available credit

Record existing home loans, personal loans, car finance, student-loan obligations and other commitments. For credit cards, include the approved limits as requested, not only the current amount owing. Lenders can treat different commitments differently.

ANZ’s borrowing calculator asks about income, dependants, expenses, repayments and total credit-card limits. Its estimate is conditional on stated assumptions and is not an offer of credit. Use that as an example of the information needed, not as a universal lending formula.

Our HECS debt and borrowing capacity guide covers student-loan considerations. Keep the detail of each debt accurate so a lender or broker can model changes without guessing.

Understand the serviceability buffer

APRA’s APS 220 standard requires an authorised deposit-taking institution to apply a mortgage serviceability buffer of at least three percentage points unless APRA determines otherwise. The assessment disregards a temporary introductory discount when applying the rule.

This is an assessment safeguard, not an extra three percentage points automatically added to your actual repayment rate. Lenders may also apply other assessment settings. Do not assume a non-bank lender uses an identical process simply because it offers home loans.

For a simplified illustration, a $500,000 principal-and-interest loan over 30 years costs about $2,998 monthly at a hypothetical 6% rate. At 9%, the equivalent repayment is about $4,023. The $1,025 difference shows why a loan affordable at today’s rate may not pass a stressed assessment.

Those figures assume monthly amortisation, unchanged rates and no fees or offsets. They are not a current offer or a complete lender serviceability calculation. The bank’s model includes more than this single repayment comparison.

The 2026 debt-to-income rule is not a personal entitlement

APRA’s May 2026 outlook explains that, from 1 February 2026, affected banks must limit the share of new mortgage lending with debt at least six times income to 20% or less, applied separately to owner-occupier and investor lending.

That portfolio limit does not mean everyone below six times income qualifies. It also is not a universal rule that no individual can ever borrow above that ratio. Your application still depends on serviceability, security, lender policy and other requirements.

Avoid replacing one oversimplification with another. “The bank lends six times salary” is not an adequate budget rule, particularly when existing debts and different income definitions may be relevant.

Use a worksheet before the calculator

Prepare these figures once and use them consistently when discussing options. Keep supporting records beside the worksheet so uncertain entries can be resolved.

Run a base scenario and a cautious scenario. If variable earnings fall or an expense rises, does the purchase still look manageable? The purpose is to identify fragility early, not to forecast every future event precisely.

Separate the lender estimate from your comfort budget

Build a post-purchase household budget using the repayment you would actually pay, then stress-test it. Add council rates, insurance, maintenance and strata costs where relevant. Leave room for irregular expenses rather than assuming every remaining dollar can support a larger mortgage.

Moneysmart’s loan guidance recommends considering affordability and comparing fees, terms and features. A longer term can reduce the instalment while increasing interest over time, so do not treat a lower monthly amount as proof of a cheaper loan.

If an offset account is part of your plan, use a realistic expected balance. Money needed for settlement or immediate repairs cannot simultaneously remain in the offset reducing interest. Our offset value guide explains that separate calculation.

Improving the position without chasing a maximum

Ask the lender or broker which documented change would matter: a smaller purchase, reduced debt, a lower unused credit limit, a larger deposit or a different timing. Request a model using your actual circumstances before taking an irreversible step.

Reducing genuine expenses can help a budget, but claiming an unrealistically low future lifestyle is not a sound strategy. Likewise, do not drain every cash reserve to improve one ratio while leaving the household exposed to the first unexpected bill.

If changing jobs, expecting parental leave or planning another major commitment, discuss it openly. A loan should be assessed with relevant foreseeable circumstances, not only the most favourable snapshot of the application month.

From estimate to conditional approval

An online calculator is a planning tool. Pre-approval involves further assessment and can still contain conditions relating to documents, the property, valuation and unchanged circumstances. Read those conditions before relying on a figure in negotiations.

Our home-loan pre-approval guide explains what to confirm. Ask the lender when the approval expires and what changes must be reported. Do not assume a calculator screenshot or informal conversation is an unconditional funding commitment.

The CompareUs Editorial Team reviewed the linked regulator, government and lender information on 28 September 2026. These examples are general education, not a credit decision or personal recommendation. Obtain a current assessment and choose a repayment budget that works for your household.