If you've applied for a home loan recently and been surprised by how much less you can borrow than you expected, the serviceability buffer is probably why. It's one of the least understood parts of the home loan process, but it affects every borrower in Australia. Here's what it is, why it exists, and what you can actually do about it.
What Is the Serviceability Buffer?
The serviceability buffer is an extra margin that lenders add on top of your actual interest rate when they work out whether you can afford a loan. It's not a rate you'll ever pay. It's a stress test.
Every bank and lender in Australia is required to check that you could still make your repayments if interest rates went up. Instead of assessing you at the rate you'll actually be charged, they assess you at that rate plus a buffer.
How the 3% Buffer Works in Practice
The Australian Prudential Regulation Authority (APRA) sets the minimum buffer that banks, credit unions, and building societies must apply. That minimum has sat at 3 percentage points since October 2021, and it's still 3% today.
Here's what that looks like in real terms. Say you're applying for a loan at an interest rate of 6%. Your lender won't just check whether you can afford repayments at 6%. They'll check whether you could still make repayments if that rate rose to 9%, even though you'll never actually be charged 9% under current conditions.
If your income, expenses, and existing debts wouldn't comfortably cover repayments at that higher rate, your borrowing amount gets reduced, or your application gets declined, even if 6% is well within your budget today.
Why Lenders Use a Buffer
The buffer exists to stop borrowers being approved for loans they can only just afford at today's rates, with no room to absorb a rate rise, a job change, or an unexpected expense. It protects you from overcommitting, and it protects the lender from a wave of borrowers defaulting if rates climb.
It's a blunt tool. It doesn't know your specific situation, your job security, or your savings habits. It applies the same margin to almost everyone, which means some financially comfortable borrowers get assessed more conservatively than their real position would suggest.
How Much Does the Buffer Reduce Your Borrowing Power?
The buffer typically reduces how much you can borrow by somewhere around 15 to 20 percent compared to an assessment at your actual rate. For a couple on a combined income of $120,000 with no children and no other debts, a 3% buffer can reduce borrowing power by roughly $150,000.
That's a meaningful difference if you're trying to buy in a competitive market, or if you're close to a price bracket you're aiming for.
Does the Buffer Apply to Every Lender?
APRA's 3% buffer requirement applies to banks, credit unions, and building societies. Non-bank lenders aren't directly regulated by APRA, though most still apply a similar buffer to meet their responsible lending obligations under ASIC. In practice, you'll come across a version of this buffer no matter who you apply with.
It's also worth knowing that APRA reviewed the 3% buffer again and chose to keep it unchanged, and has since introduced additional limits on higher debt-to-income lending. None of this is about to loosen. If anything, the regulatory settings around borrowing capacity are getting more cautious, not less.
What You Can Do About It
You can't get the buffer waived. But you can improve how you're assessed against it:
- Pay down or close credit cards, buy-now-pay-later accounts, and personal loans you're not using, since lenders count the full available limit, not just what you owe
- Review your everyday spending in the months before you apply, as banks assess your declared living expenses closely
- Compare how different lenders calculate income and expenses, since policies vary more than most people expect
- Get an accurate read on your borrowing power before you start house hunting, so you're not disappointed partway through a purchase
This is exactly where a broker earns their keep. We know which lenders apply the buffer strictly and which have more flexibility in how they treat things like overtime income, rental income, or existing debts. The right structure and the right lender can make a genuine difference to your borrowing capacity, even with the same 3% buffer in place.
Get a Clear Answer on What You Can Borrow
Instead of guessing how the serviceability buffer will affect your application, book a free chat with the Swish team. We'll walk you through exactly how much you're likely to be able to borrow, and which lenders are the right fit for your situation.
