The Australian Prudential Regulation Authority (APRA) sets the serviceability standards that banks and authorised deposit-taking institutions must follow when assessing residential mortgage applications. As of mid-2026, the key requirement is the 3.0 percentage-point serviceability buffer: lenders must assess whether a borrower can repay the loan at the product interest rate plus a buffer of 3%. That means if a lender offers a mortgage at 5.5%, the assessment rate applied to the applicant’s financials is 8.5%. This buffer substantially reduces the maximum loan amount a borrower can qualify for compared to what they could afford at the advertised rate. A second significant constraint, effective from February 2026, is the debt-to-income (DTI) limit: banks must ensure that new lending to borrowers with a DTI ratio of 6 or above does not exceed 20% of each institution’s total new residential lending portfolio. Together, the serviceability buffer and DTI cap define the borrowing power landscape for Australian home buyers in 2026. This article explains how these rules work, what income sources lenders count, and how the buffer interacts with existing debts and living expenses. For stamp duty costs in specific states, see our articles on NSW stamp duty and VIC stamp duty.
The 3% serviceability buffer explained
APRA introduced the 3% buffer in October 2021 as a macroprudential measure to reinforce financial stability amid rising household debt. The buffer has been confirmed as remaining at 3% through May 2026. Under this rule, when a lender assesses a loan application, they must calculate the borrower’s ability to meet repayments using an interest rate that is the higher of the product rate plus 3%, or a specified floor rate set by the lender (which APRA expects to be at least 1% above the product rate).
The practical effect is significant. Consider a borrower seeking a 30-year principal-and-interest mortgage. At the product rate of 5.5%, monthly repayments on a $500,000 loan are approximately $2,839. But the lender must assess the borrower at 8.5%, where the monthly repayment is roughly $3,844 — a 35% increase in the assumed repayment. This higher figure must fit within the lender’s net income surplus calculation after accounting for living expenses, other debts, and a margin for interest rate movements.
APRA does not mandate a specific maximum loan-to-value ratio (LVR) through this buffer — that remains a commercial decision for each lender — but the buffer indirectly limits LVR by constraining the dollar amount of the loan.
How lenders calculate your borrowing capacity
Each lender applies its own serviceability calculator, but all must comply with the 3% buffer floor. The general framework follows a common pattern:
First, the lender determines gross assessable income. This includes base salary, and may include a portion of bonus, commission, overtime, rental income, and investment returns. Most lenders shade variable income — typically accepting 80% of bonus and commission income, often averaged over two years. Rental income from investment properties is typically shaded to around 75–80% of gross rent to account for vacancies and expenses.
Second, the lender deducts living expenses. Since the introduction of comprehensive credit reporting and the Banking Code of Practice, lenders have moved from the Household Expenditure Measure (HEM) benchmark toward more detailed expense verification. Applicants should be prepared to provide bank statements showing actual spending across categories such as groceries, utilities, transport, insurance, childcare, and discretionary items.
Third, the lender deducts commitments: existing loan repayments (assessed at the buffered rate), credit card limits (typically assessed at 3% of the limit per month, regardless of the balance actually carried), personal loans, car leases, and HECS/HELP repayments.
Finally, the lender applies the buffered assessment rate to the proposed new loan and checks whether a net surplus remains. Most lenders require a small monthly surplus (often in the range of $100 to $500) as a buffer against further interest rate rises or expense increases.
Debt-to-income cap from February 2026
In February 2026, APRA introduced a new rule limiting high-DTI lending. Banks must ensure that new residential mortgage lending with a DTI ratio of 6 or above does not exceed 20% of each institution’s total new lending in any given period. DTI is calculated as total debt divided by gross annual income. Total debt includes the proposed new loan plus all existing debts.
A DTI of 6 means a borrower’s total debts equal six times their gross annual income. For a household earning $150,000, that translates to total debts of $900,000. If the household already has a $50,000 car loan and a $30,000 personal loan, the remaining capacity for a mortgage under the DTI cap is $820,000 — even if the serviceability buffer would permit a higher amount.
The 20% portfolio cap means borrowers with high DTI ratios are not automatically excluded from lending, but they may face greater scrutiny, fewer lender options, or higher interest rates as banks manage their portfolio composition. First-home buyers entering markets with high property prices relative to incomes are the cohort most affected by the DTI constraint.
How different income types are treated
Lenders classify income into categories, and the treatment varies substantially:
- PAYG salary (full-time or permanent part-time): 100% accepted. This is the most favourably treated income type.
- Casual or contract employment: Generally accepted if the applicant has been in the role for at least 6 to 12 months and can demonstrate continuity. Some lenders require a letter from the employer confirming ongoing engagement.
- Self-employment: Typically requires two years of tax returns and notices of assessment. Lenders use an average of the most recent two years’ taxable income, often with add-backs for non-cash expenses such as depreciation.
- Rental income: Usually shaded to 75–80% of gross rent for serviceability, although the full rental income is included in the DTI denominator for the DTI cap.
- Investment income: Dividends and distributions are generally accepted at 80–100% depending on consistency and the lender’s policy. Interest income is accepted at the current rate.
Applicants with less straightforward income profiles may benefit from consulting a lending specialist. Arrivau’s team of licensed professionals can provide individual borrowing capacity assessments within one business day.
Strategies to increase borrowing power
Borrowers looking to maximise their borrowing capacity within APRA’s framework can take several practical steps. Reducing or closing unused credit cards has a disproportionate effect because lenders assess the limit, not the balance. A credit card with a $15,000 limit reduces borrowing capacity by approximately $30,000 to $50,000 depending on the lender’s calculator, even if the card is paid off in full each month.
Paying down personal loans, car finance, and buy-now-pay-later accounts before applying also increases assessable surplus. Applicants with HECS/HELP debts should be aware that compulsory repayments are deducted from net income in serviceability calculations; paying off a small remaining HELP balance can free up meaningful borrowing capacity.
Reducing living expenses by providing detailed bank statements that show disciplined spending — as opposed to the lender defaulting to a higher benchmark — can also lift the assessed surplus. Finally, structuring income to maximise the proportion classified as base salary (rather than variable bonus) will improve borrowing power since base salary is accepted at 100%.
Frequently asked questions
Does the 3% buffer apply to refinancing? Yes. APRA applies the same serviceability standard to new lending and refinancing, including switching between lenders. Borrowers refinancing with their existing lender may encounter some flexibility, but the buffer generally applies.
Are non-bank lenders subject to APRA’s buffer? APRA’s rules apply to authorised deposit-taking institutions (ADIs) — banks, credit unions, and building societies. Non-bank lenders are not directly regulated by APRA, but many adopt similar serviceability standards as a matter of market practice and to satisfy their wholesale funders.
How does the buffer interact with fixed-rate loans? For fixed-rate loans, lenders assess serviceability at the higher of the fixed rate plus 3% or the revert rate (the variable rate the loan converts to after the fixed period ends) plus 3%. This means fixed-rate borrowers may face a higher assessment rate than variable-rate borrowers if the revert rate is substantially above the fixed rate.
Can I borrow more if interest rates fall? Yes, all else being equal. As product rates decline, the buffered assessment rate also declines, which increases borrowing capacity. However, APRA reviews the buffer periodically and may adjust it if rates fall substantially.
What is APRA’s floor rate? APRA expects lenders to maintain a floor rate for serviceability assessments that is at least 1 percentage point above the product rate, in addition to the buffer. In practice, the 3% buffer almost always produces an assessment rate well above any floor, so the floor rate rarely binds.
Data sources
- APRA Prudential Practice Guide APG 223 — Residential Mortgage Lending
- APRA macroprudential policy framework and buffer announcements
- APRA February 2026 DTI lending limit confirmation
- Australian Banking Association — Banking Code of Practice
- APRA quarterly authorised deposit-taking institution statistics
Disclaimer: This article provides general information only and does not constitute financial, tax, or legal advice. Readers should confirm current rates and thresholds with the Australian Taxation Office or a licensed professional before making decisions. Data current as at July 2026.