What Happens to Your Mortgage If the RBA Raises Rates by 1%?

If the RBA raises rates by 1%, your mortgage repayment does not go up by a cute little token amount. It can mean hundreds of dollars extra every month, which is a very rude way to discover your budget was already doing yoga just to stay flexible.

The good news is the maths is predictable. A 1% rise feels scary because it sounds abstract. Once you turn it into dollars, you can actually plan for it. That is the whole game.

In this guide, we will walk through what a 1% rise really means, why your lender might pass it on, which borrowers get hit hardest, and what you can do before the next rate move instead of after it.

First, does a 1% RBA rise mean your mortgage rises by exactly 1%?

Not necessarily. The RBA sets the cash rate. Your lender sets your home loan rate. When the cash rate moves, banks often pass on all or most of the change to variable-rate borrowers, but they do not have to match it perfectly.

So when people say, "what if the RBA raises rates by 1%?", what they usually mean is: what if my mortgage rate ends up 1 percentage point higher? That is the scenario worth stress-testing.

If you want the quick answer for your own numbers, use the Rate Rise Impact Calculator. If you want the full breakdown first, keep going.

What a 1% rise looks like in real dollars

Here are a few simple examples using standard principal-and-interest repayments over 30 years.

• $400,000 loan: 6.0% = about $2,398/month. 7.0% = about $2,661/month. Increase = $263/month.
• $500,000 loan: 6.0% = about $2,998/month. 7.0% = about $3,327/month. Increase = $329/month.
• $600,000 loan: 6.0% = about $3,597/month. 7.0% = about $3,992/month. Increase = $395/month.
• $700,000 loan: 6.0% = about $4,197/month. 7.0% = about $4,657/month. Increase = $460/month.
• $900,000 loan: 6.0% = about $5,396/month. 7.0% = about $5,988/month. Increase = $592/month.

That is why a 1% rise matters. It is not just a line on the news. It can be a grocery bill, a car payment, or the entire amount you were hoping to save each month.

Why the jump can feel worse than expected

Mortgage repayments are not linear. When rates rise, you are not just paying a bit more interest on this month. The whole remaining repayment schedule is recalculated around a higher rate.

That is why the extra monthly cost often feels bigger than people expect. If your balance is still large and your term is still long, a rate rise has plenty of debt to work on. Which is, frankly, pretty efficient if you are a bank and less fun if you are you.

Borrowers most exposed to a 1% rise are usually:

• people who bought recently and have not paid down much principal yet
• households with large loans relative to income
• borrowers who rolled off ultra-low fixed rates onto variable rates
• anyone whose budget already relies on things "probably being fine"

But don’t banks already test you for higher rates?

Yes, in theory. APRA expects lenders to assess most new home loan applicants using a serviceability buffer of at least 3 percentage points above the loan product rate. That means someone applying for a loan at 6.0% would generally be tested around 9.0%.

That buffer helps, but it does not make you bulletproof. Life changes. Childcare appears. Insurance gets more expensive. Grocery bills become a personality test. Just because you technically passed serviceability two years ago does not mean a fresh 1% rise feels comfortable today.

If you are not sure how much room you have left, the Borrowing Capacity Calculator is a handy way to sanity-check how lenders think versus how your household budget actually feels.

What if you are on a fixed rate?

If you are fully fixed, your repayment usually stays the same during the fixed term, even if the RBA moves rates. That is the point of fixing.

The catch is what happens later. When a fixed term ends, borrowers typically roll onto the lender's revert rate or refinance elsewhere. If market rates are much higher by then, the jump can be brutal. Plenty of Australians learned this the hard way after the 2022-2023 hiking cycle.

So if you are fixed today, a 1% rise may not hit you immediately. But it still matters for your next rate, your refinance options, and your future budget.

How to prepare before your lender emails you

1. Stress-test your current repayment

Do the boring but useful thing. Calculate what your loan would cost if your rate rose by 1%. Then ask whether your current cash flow can absorb that without turning every weekend into a no-spend monastery.

Even if the RBA never moves a full 1% in one hit, modelling the bigger scenario gives you a buffer. That is the financial equivalent of packing an umbrella instead of staring at the sky and hoping for the best.

2. Build a buffer in offset or savings

If your loan has an offset account, extra cash parked there reduces interest while staying accessible. That is useful when rates are high because every dollar in offset effectively earns you your mortgage rate, tax free.

If you do not have offset, plain old savings still matter. A few months of higher repayments sitting in cash can turn a nasty surprise into an inconvenience.

3. Review your rate, not just your spending

People often go straight into budget-cut mode when rates rise. Fair enough. But sometimes the faster win is calling your lender or refinancing. If your current rate is uncompetitive, shaving even 0.30% to 0.60% off the loan can soften a future rate rise quite a bit.

Use the Refinance Calculator to see whether switching could save enough to be worth the paperwork. Sometimes the bank loyalty tax is real.

4. Cut expenses that recur, not just fun ones

When budgets tighten, people tend to attack coffee, takeaway and streaming first because they are visible. That helps a bit, but bigger recurring costs usually matter more: insurance premiums, unused subscriptions, phone plans, school fees, car loans, and the four separate apps someone in the house swears are all essential.

The goal is not misery. The goal is finding enough monthly breathing room that a rate rise does not control the entire household mood.

Should you refinance before rates rise?

Maybe. It depends on three things:

1. your current rate compared with what competitors are offering
2. your loan features like offset, redraw and flexibility
3. your costs to switch including discharge, settlement and any break fees

If your variable rate is already high, waiting for another move is usually not a great hobby. Get quotes now. Even if you stay put, having a better offer from another lender can help you negotiate.

And if you want actual lender options rather than spreadsheet therapy, talk to a broker. They can compare products, features and policies much faster than most borrowers doing it solo at 11:47 pm.

What a 1% rise means psychologically

This part gets ignored, but it matters. A mortgage rate jump changes behaviour before it changes balance sheets. Households pull back. Renovations get delayed. Travel plans shrink. People stop feeling "ahead" and start feeling like they are managing risk full-time.

That is why getting ahead of the numbers matters so much. If you already know your worst-case monthly repayment and have a plan for it, the next rate headline feels annoying, not paralysing.

The simple takeaway

A 1% mortgage rate rise is a real hit for most Australian borrowers. On a $500,000 loan, it is roughly an extra $329 a month. On a $900,000 loan, it is closer to $592 a month. That is not the kind of difference you want to "just wing".

Run your numbers. Build some buffer. Review your rate. And if your current loan is already a bit ugly, fix that before the RBA gives you another reason to.

Sources

• Reserve Bank of Australia: Interest rate decisions
• Reserve Bank of Australia: Cash rate series
• APRA: Macroprudential policy and credit measures