The APRA serviceability buffer is a regulatory requirement that all authorised deposit-taking institutions (ADIs) — banks, credit unions and mutual banks — must apply when assessing home loan applications. It requires lenders to test whether a borrower can afford their repayments at a rate of at least 3% above the loan's actual interest rate. In practice, this reduces every borrower's maximum loan amount significantly relative to what they would qualify for at the actual loan rate.
How the 3% Serviceability Buffer Works in Practice
When a lender receives a home loan application, it must calculate whether the borrower can afford the loan at the test rate — which is the actual loan interest rate plus 3%. If you are applying for a variable rate loan at 6.0% p.a., the lender tests your repayment ability at 9.0% p.a. The repayment at 9.0% on a $600,000 loan over 30 years is approximately $4,828 per month, compared to $3,597 at 6.0%. The lender needs your income and expenses (under the HEM benchmark) to support the 9.0% repayment — not the actual 6.0% repayment.
This test reduces maximum borrowing capacity by approximately 20–25% compared to what borrowers could access without the buffer. For a borrower who qualifies for $800,000 at the actual loan rate, the buffer may restrict them to approximately $620,000–$650,000 — a material difference in purchasing power.
The Buffer Also Applies to Fixed Rate Loans
The 3% buffer applies to both fixed and variable rate loan applications. For a 5-year fixed loan at 5.8% p.a., the assessment rate would be 8.8% p.a. — regardless of the fact that the rate is locked in for five years. The buffer accounts for the rate that will apply after the fixed period expires and the loan reverts to variable.
Why APRA Introduced and Maintained the 3% Buffer
APRA introduced the 3% floor (up from 2.5%) in October 2021 as a macroprudential policy measure to reduce systemic risk in Australian mortgage lending. At the time, property prices were rising rapidly, interest rates were at historic lows, and debt levels relative to income were at all-time highs. The buffer was designed to ensure borrowers had capacity to absorb rate increases — which proved prescient when the RBA increased the cash rate by 4.25% between May 2022 and November 2023.
In the current rate environment (2026), with rates having fallen from their peak, there has been debate about whether the 3% buffer remains appropriate. However, as of March 2026, APRA has maintained the 3% floor, citing the importance of building resilience in the housing lending market and the long-term nature of mortgage debt. APRA has indicated it will continue to monitor conditions and may adjust the buffer if warranted by macro conditions.
Non-Bank Lenders May Use Different Buffers
APRA's buffer requirement applies only to ADIs (banks and credit unions). Non-bank lenders (who are regulated by ASIC but not APRA) are not required to apply the same 3% buffer. Some non-bank lenders use a lower buffer (2% or 2.5%), which can result in materially higher maximum loan amounts. This is a legitimate strategy for some borrowers — a broker can identify which lenders suit your situation.
How to Maximise Your Borrowing Capacity Within the Buffer
While the buffer itself cannot be avoided with ADIs, there are multiple strategies to maximise what you can borrow within it. The most effective are: reducing credit card limits (each $10,000 of credit limit reduces borrowing capacity by approximately $65,000–$75,000); closing personal loans and car loans ahead of application; ensuring all income types you receive are documentable and meet lender policies; and comparing lenders — serviceability assessments vary between lenders due to different HEM tables, income shading rates and expense models.
Your mortgage broker can run serviceability assessments across multiple lenders to identify who offers the highest capacity for your income and expense profile. In some cases, the difference between the highest and lowest capacity across lenders is $100,000 or more for the same borrower — making lender selection a critical part of the process.
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About the Author
Sakib Manzoor
Senior Finance Wellness Expert
Sakib Manzoor is the founder of Secure Finance and brings extensive experience in Australian mortgage broking and financial wellness. Specialising in helping clients achieve their property finance goals through personalised strategies and expert guidance, Sakib is FBAA accredited and committed to providing clear, actionable advice. All content is written to meet Australian regulatory standards and is regularly updated to reflect current market conditions.