What Is the Mortgage Serviceability Buffer in Australia?

The mortgage serviceability buffer is the extra margin Australian lenders add to a home loan's interest rate when testing whether you could afford the repayments. APRA requires banks and other authorised deposit-taking institutions (ADIs) to apply a buffer of at least 3 percentage points, so a loan at 6% is tested at 9% or more. The buffer affects the test, not the rate you actually pay.

Quick Answer

The serviceability buffer is a safety margin built into home loan assessments. In short: 1.What it is: a set number of percentage points added to the loan's interest rate to create a higher “assessment rate”. 2.How big it is: for ADIs, APRA's minimum is 3 percentage points above the loan's product rate, and individual lenders may apply more. 3.What it does: it lowers the loan size your income can be assessed as supporting, because the repayments used in the test are higher than the ones you would actually make. 4.What it doesn't do: it doesn't raise your actual interest rate or your repayments.

Key takeaways

The 3% serviceability buffer is a test, not a cost. You repay at your actual loan rate. The higher rate is used only to check that you could cope if your circumstances or interest rates changed.

APRA sets the minimum for ADIs. APRA-regulated ADIs, including banks, credit unions and building societies, must apply at least 3 percentage points. Non-bank lenders' serviceability policies aren't governed by APRA's ADI standards in the same way.

The setting has been stable since October 2021. APRA raised the buffer from 2.5 to 3.0 percentage points that month and confirmed it again on 28 May 2026.

The buffer has a large effect on capacity. In the illustrative example below, the same monthly surplus supports roughly a quarter less borrowing at a 9% assessment rate than at a 6% one.

Lenders differ. The buffer is a floor. Income treatment, expenses, floor rates and exceptions all vary between lenders, so results differ.

What is the mortgage serviceability buffer?

When you apply for a home loan, the lender must decide whether you can afford the repayments, now and later. It doesn't test you at today's rate alone. It adds a buffer, expressed in percentage points, and checks that your income would still cover the repayments at that higher rate. APRA describes the buffer as a contingency for rises in interest rates over the life of the loan, as well as for unforeseen changes in a borrower's income or expenses. In its May 2026 announcement, APRA said the buffer helps ensure recent new borrowers can keep servicing their loans if expenses and interest rates rise. Put simply, the buffer answers a question the lender needs to ask: “If things get tighter, would this borrower still be able to repay?”

Serviceability buffer, assessment rate and floor rate: what's the difference?

These terms are often used interchangeably, but they mean different things:

Term	What it means
Product rate	The interest rate on the loan you are applying for, which is the rate your repayments are actually based on.
Serviceability buffer	The margin added on top of the product rate for the affordability test. For ADIs, APRA's minimum is 3.0 percentage points.
Assessment rate	The product rate plus the buffer. It is the rate the lender uses to test your repayments, and it is not the rate you pay.
Floor rate	A minimum assessment rate that some lenders set in their own policy. Where one applies, the assessment rate can be higher than the product rate plus 3 points.

What the 3% serviceability buffer looks like in dollars

These figures are simplified and hypothetical: a $600,000 principal-and-interest loan over 30 years. They are not lender rates, policies or a forecast.

Loan rate	Assessed at	Actual repayment (monthly)	Assessed repayment (monthly)	Difference
5.00%	8.00%	about $3,221	about $4,403	about $1,182
6.00%	9.00%	about $3,597	about $4,828	about $1,230
7.00%	10.00%	about $3,992	about $5,265	about $1,274

At a 6% loan rate, the lender needs the borrower's assessed surplus to cover about $4,828 a month, even though the actual repayment would be about $3,597. The difference of roughly $1,230 is headroom the lender wants to see before approving the loan. It is not an extra charge.

Why APRA sets a serviceability buffer

APRA's job is to protect the stability of the financial system, and household debt is a central concern. It has repeatedly cited high household indebtedness as a reason for keeping the buffer in place, along with cost-of-living pressures and an uncertain economic outlook. The 2021 increase came at a time of rapid growth in higher-risk lending. In the June 2021 quarter, more than 20 per cent of ADIs' new lending went to borrowers with debts of more than six times their pre-tax income. APRA chose the buffer as its tool because it applies to every borrower's assessment, rather than only to the highest-debt cohort.

Who has to apply the APRA serviceability buffer?

APRA's serviceability buffer applies to authorised deposit-taking institutions (ADIs): banks, credit unions and building societies. Non-bank lenders that provide regulated consumer credit are subject to applicable responsible lending obligations under the credit legislation, while their serviceability policies are not governed by APRA's ADI prudential standards in the same way. APRA's April 2026 material indicated that non-ADIs accounted for less than 5 per cent of housing lending at that time. A lender that isn't bound by the APRA buffer may still test affordability with its own margin, so you shouldn't assume a non-bank test is looser. Check the specific lender's policy.

How the buffer has changed

When	What happened
Before October 2021	APRA's guidance (APG 223) expected a prudent ADI to apply a buffer of at least 2.5 percentage points.
6 October 2021	APRA raised the minimum to 3.0 percentage points above the loan product rate, citing high household debt and a rising share of high debt-to-income lending.
December 2023, November 2024, July 2025	APRA kept the buffer at 3 percentage points at its macroprudential reviews.
28 May 2026	APRA confirmed that the buffer would remain at 3 percentage points, citing high household indebtedness, cost-of-living pressures and an uncertain outlook.

APRA reviews its macroprudential settings regularly and has said it will adjust them if needed. No change has been announced since 28 May 2026 at the time of writing, and nobody can reliably predict when, or in which direction, the next one will come.

How much the buffer affects home loan serviceability

The effect is easy to underestimate. Suppose a lender concludes that a household has $4,000 a month available to service a new loan, and the loan is a 30-year principal-and-interest loan at a hypothetical 6.00%. This is what different buffers would do to the loan that surplus supports: Illustrative arithmetic only. Real assessments involve income, expenses and commitments that vary by lender.

Buffer	Assessed at	Loan the surplus supports	Change vs 3.0 points
None	6.00%	about $667,000	+34%
2.0 points	8.00%	about $545,000	+10%
2.5 points	8.50%	about $520,000	+5%
3.0 points (APRA minimum)	9.00%	about $497,000	—
3.5 points	9.50%	about $476,000	−4%

When APRA raised the buffer in 2021, it estimated that, other things equal, a 0.5 percentage point increase would reduce the typical borrower's maximum borrowing capacity by around 5 per cent. The example above is in the same range: moving from 2.5 to 3.0 points trims capacity by roughly 4 to 5 per cent. Your own numbers will differ. APRA has also noted that the buffer is applied to a borrower's other existing debts, not only the new loan. This is one reason credit card limits and other commitments can weigh heavily on capacity.

When interest rates move

The buffer remains at 3 percentage points unless APRA changes it. For lenders that calculate the assessment rate by adding the buffer to the product rate, the assessment rate will generally move when the loan rate changes. A lender's floor rate may produce a higher assessment rate. On 29 September 2026 the Reserve Bank raised the cash rate target by 25 basis points to 4.60 per cent. Each lender decides its own variable rates and when to change them, so the effect on your assessment depends on the lender and product. As a rough guide, in the illustrative example above, an assessment rate 0.25 percentage points higher trims the supportable loan by a little over 2 per cent.

The buffer and other lending settings

The buffer is one part of a wider assessment. Lenders also look at your income, verified living expenses, existing debts and credit history. For ADIs, APRA has also limited new lending at a debt-to-income (DTI) ratio of six or more since February 2026, to no more than 20 per cent of new owner-occupier lending and 20 per cent of new investment lending, subject to applicable exemptions. That is a limit on each lender's lending mix, not a personal cap on you. For a step-by-step look at how these inputs combine, see our guide to how Australian banks calculate borrowing capacity [VERIFY VIP FINANCE URL].

Refinancing and the buffer

A lender assessing a refinance will run its own serviceability test, and for an ADI the buffer is part of that test. That means a borrower who comfortably meets today's repayments can still fail the assessment if the buffered repayments are higher than their surplus can support. APRA has acknowledged that some borrowers refinancing to another lender may not pass the buffer requirement. APRA's framework lets ADIs approve loans outside their standard criteria, including the buffer, through exceptions to policy, provided they are managed prudently and kept limited. For a refinance, a lender might consider things like repayment history. Whether a lender offers exceptions, and when, is its own credit policy, so nothing here should be read as a promise that a refinance will be approved.

Common buffer misunderstandings

“The buffer is the rate I'll pay.” It isn't. Your repayments are based on your actual loan rate.

“The buffer predicts where rates will go.” It doesn't. It is a margin for safety, not a forecast.

“Every lender uses exactly 3 points.” For ADIs, 3 points is the minimum. Some lenders add their own margin or floor rate.

“The buffer is the only thing limiting my borrowing.” Income treatment, expenses, commitments and credit history matter as well.

“Borrowing up to the assessed limit is safe.” The assessment shows what a lender is prepared to offer, not what suits your budget.

What borrowers commonly review when the buffer limits capacity

This is general information, not personal advice. Borrowers whose results are lower than expected often look at:

Existing commitments: credit card limits, buy now pay later accounts, personal and car loans. Understand the consequences before changing anything.

Living expenses: whether the figures declared match what bank statements show.

Loan structure and term: how the term and repayment type affect the assessed repayment.

Lender differences: how different lenders treat income, expenses and commitments.

The amount borrowed: whether borrowing less than the maximum better suits the household's budget.

Risks and limitations

Passing the buffer isn't an approval. Final approval also depends on the property valuation, your documents and the lender's policy at the time.

The buffer doesn't remove risk. Rates and personal circumstances can still change beyond what an assessment allows for.

Settings can change. APRA's settings and lender policies are reviewed from time to time, so confirm current rules before relying on them.

Lender policies vary. Floor rates, income treatment and exceptions differ between lenders.

This is general information. It doesn't take your objectives, financial situation or needs into account.

How VIP Finance can help

VIP Finance has an extensive network of lenders and compares loan options based on your circumstances. Because each lender treats income, expenses and commitments differently, a broker can help you understand how your situation may be assessed across different lenders. That covers first home buyers, people upgrading and homeowners looking to refinance. What is pre-approval? It is a lender's conditional assessment of how much you may be able to borrow before you buy, based on the documents you've provided. It helps you set a budget, but it isn't a guarantee of final approval.

Want to see how lenders would assess you?

The 3 percentage-point minimum applies across ADIs, but each lender can apply its own credit policy to income, expenses, commitments, floor rates and exceptions. The VIP Finance team can explain what lenders look at and which policies might apply to your situation, with no obligation. Home Loans: https://vipfin.com.au/services/home-loans/ First Home Buyers: https://vipfin.com.au/services/first-home-buyers/ Contact VIP Finance: https://vipfin.com.au/contact-us/

Frequently Asked Questions

What is the mortgage serviceability buffer in Australia?

It is the margin lenders add to a home loan's interest rate to test whether you could afford the repayments if rates or your circumstances changed. APRA requires ADIs to apply a minimum of 3 percentage points.

Is the serviceability buffer 3%?

For ADIs, APRA's minimum buffer is 3 percentage points above the loan's product rate. Individual lenders may apply a higher margin or a floor rate under their own credit policy.

Do I pay the buffer rate on my home loan?

No. The buffer is used only in the affordability test. Your repayments are based on the actual rate on your loan.

Does the buffer apply to every lender?

APRA's buffer applies to ADIs. Non-bank lenders' serviceability policies aren't governed by APRA's ADI standards in the same way, but they are subject to responsible lending obligations for regulated consumer credit, and they may use their own margins.

Does the serviceability buffer apply when I refinance?

A lender assessing a refinance will run its own serviceability test, and for an ADI the buffer is part of it. APRA allows prudently managed, limited exceptions, but whether one is available depends on the lender's policy.

How much does the buffer reduce borrowing capacity?

It depends on your income, expenses, debts and the rate. When APRA raised the buffer in 2021, it estimated that each 0.5 percentage point reduces the typical borrower's maximum capacity by around 5 per cent, other things equal.

Will APRA change the serviceability buffer?

APRA reviews its macroprudential settings regularly and confirmed the 3 percentage point buffer on 28 May 2026. It has said it will adjust settings if needed. Future changes can't be predicted.

What is the difference between the buffer and a floor rate?

The buffer is the margin added to the loan rate. A floor rate is a minimum assessment rate that some lenders set in their own policy, so the assessment rate can be higher than the loan rate plus 3 points.

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