For many Australians, comparing today’s interest rates with the 17% rates of the late 1980s and early 1990s seems straightforward.

Seventeen per cent sounds dramatically worse than 4.6%.

Yet the comparison is not that simple.

Australia’s cash rate is now 4.60%, following another 25-basis-point increase by the Reserve Bank of Australia in September 2026. At the same time, households are carrying much larger mortgages relative to their incomes and property values are substantially higher.

That creates an important question:

Can a 4.6% interest rate create more financial pressure than 17% did in 1990?

Recent analysis suggests that, when measured by the share of household income going towards interest payments, today’s mortgage burden can indeed be comparable with — and in some measures exceed — the burden experienced during the early 1990s.

Why Comparing Interest Rates Alone Can Be Misleading

The headline interest rate is only one part of the mortgage equation.

What really matters to a household is how much of its income is required to service its debt.

Consider two hypothetical homeowners.

One has a $100,000 mortgage at 17%.

Another has a $700,000 mortgage at 4.6%.

The second homeowner has a much lower interest rate, but the amount of debt is dramatically larger.

That is the key difference between the two periods.

Australian households today generally have much larger mortgages relative to their incomes and face significantly higher property prices.

As a result, a lower interest rate can still translate into a substantial repayment burden.

Australian Mortgages Are Much Larger Today

Property prices have risen significantly over the decades.

That means borrowers who purchase a home today may need to take on hundreds of thousands — or even more than a million dollars — in debt.

The Reserve Bank has previously highlighted the long-term rise in Australia’s dwelling prices relative to household incomes and the way greater access to credit has influenced housing affordability.

The result is a different type of interest-rate environment.

In the early 1990s, interest rates were extraordinarily high, but mortgage balances were generally much smaller in dollar terms.

Today, rates are far lower, but the underlying debt can be substantially larger.

The Numbers Behind the 1990 Comparison

The RBA’s cash rate reached 17.5% in 1990, while standard variable housing rates were around 17%.

At first glance, that makes today’s 4.6% cash rate look relatively modest.

However, KPMG’s analysis of Australian Bureau of Statistics data found that interest payments as a share of household income reached 5.7% in early 1990.

More recently, Australian households have faced an interest burden at similar or higher levels.

KPMG’s analysis found that interest payments on debt peaked at 5.9% of household income in late 2023, compared with 5.7% during the 1989–90 period.

This does not mean every homeowner today is worse off than every homeowner in 1990.

Households have very different incomes, mortgages, deposits and financial circumstances.

But it does demonstrate why looking only at the interest rate can give a misleading picture of mortgage stress.

Why Modern Homeowners Can Feel More Pressure

There are several reasons a 4.6% environment can still create significant financial pressure.

1. House Prices Are Much Higher

The price of a home determines how much a buyer needs to borrow.

When property prices rise faster than household incomes, buyers often need larger mortgages to enter the market.

A lower interest rate applied to a very large loan can therefore produce a significant repayment.

2. Household Debt Has Increased

Australia has become a highly leveraged housing market.

Many households carry substantial mortgage balances, particularly recent buyers who purchased properties at elevated prices.

When interest rates rise, the impact is multiplied by the size of the outstanding loan.

3. Household Income Has Not Increased at the Same Pace as Property Prices

A mortgage becomes harder to manage when repayments consume a growing share of household income.

This is why affordability cannot be measured simply by asking whether today’s interest rate is lower than it was in 1990.

The more useful question is:

How much of a household’s income is required to service the debt?

A Simple Example

Imagine two households.

Household A — 1990

• Mortgage: $150,000
• Interest rate: 17%
• Annual interest: approximately $25,500

Household B — Today

• Mortgage: $700,000
• Interest rate: 4.6%
• Annual interest: approximately $32,200

These are only illustrative examples and do not represent average Australian mortgages.

They demonstrate the basic principle, however.

A dramatically lower interest rate does not automatically mean a lower dollar cost of borrowing when the underlying mortgage is much larger.

Actual repayments will also depend on the loan term, principal repayments, fees and whether the interest rate changes.

The 4.6% Cash Rate Does Not Mean Everyone Pays 4.6%

Another important distinction is the difference between the RBA cash rate and the interest rate charged on a mortgage.

The cash rate is the rate used by the RBA as its monetary policy target. It influences other interest rates throughout the economy, including mortgage rates.

A homeowner’s actual mortgage rate depends on their lender, loan product, borrowing profile and any discounts that apply.

Therefore, homeowners should not assume that a 4.60% cash rate means their mortgage is charging exactly 4.60%.

Why Higher Rates Can Affect More Than the Mortgage

The impact of higher interest rates does not stop at the monthly mortgage payment.

When repayments increase, households may have less money available for other spending.

For example, a family facing an additional $1,000 a month in mortgage costs has $1,000 less available for other purposes.

That can mean reducing:

• Dining and entertainment
• Holidays
• New cars
• Home renovations
• Retail spending
• Investments
• Savings
• Business expenditure

This is one reason monetary policy can affect the broader Australian economy.

The RBA has noted that tighter financial conditions are designed to reduce aggregate demand when inflation is too high.

Higher Interest Rates Also Affect Businesses

The same principle applies to Australian businesses.

A business with debt may face higher interest expenses when rates rise.

At the same time, its customers may have less disposable income because they are paying more towards their mortgages.

This can create pressure from both directions.

A business could face:

Higher finance costs + weaker customer spending = tighter cash flow

For small businesses, maintaining a healthy cash-flow position therefore becomes particularly important during periods of higher interest rates.

Why Today’s Mortgage Pressure Matters for the Property Market

Higher mortgage costs can also feed back into property prices.

When borrowing becomes more expensive:

1. Buyers can afford to borrow less.
2. Their maximum purchasing budget falls.
3. Some buyers delay entering the market.
4. Sellers face a smaller pool of potential buyers.
5. Transaction activity can weaken.
6. Property prices can come under pressure.

This is already visible in the current market.

The RBA said in September that housing prices had fallen in most capital cities and that new housing loans had declined noticeably.

Recent property data also shows capital-city values continuing to fall, with higher interest rates weighing on borrowing capacity and buyer demand.

Could Another Rate Rise Make the Pressure Worse?

It could.

The RBA has indicated that it remains focused on returning inflation to target and is prepared to respond to changing economic conditions.

For highly leveraged households, even a relatively small increase in borrowing costs can have a meaningful impact.

For example, a homeowner with a $700,000 mortgage may feel a very different level of pressure from a rate increase than someone with a $150,000 mortgage.

This is why the size of the debt matters just as much as the interest rate itself.

What Should Homeowners Do When Interest Rates Are High?

Homeowners do not need to predict exactly where interest rates will go to improve their financial position.

Instead, they can focus on understanding their own numbers.

Consider reviewing:

Mortgage Repayments

Know exactly how much of your monthly income is going towards your mortgage.

Interest Rate

Check your current rate and understand whether it remains competitive.

Loan Balance

A larger outstanding balance means greater exposure to changes in interest rates.

Cash Buffer

An emergency fund or offset balance can provide additional flexibility when household expenses increase.

Other Debt

Credit cards, personal loans and car finance can add further pressure to household cash flow.

Future Rate Scenarios

Consider whether your budget could handle another increase in repayments.

What Should Business Owners Consider?

For business owners, higher interest rates are a reminder that cash flow should be actively managed rather than reviewed only at tax time.

Businesses with loans, equipment finance or property exposure should understand how changes in interest costs could affect profitability and cash reserves.

It may also be worth reviewing:

• Business debt
• Loan structures
• Interest expenses
• Tax obligations
• Cash reserves
• Pricing
• Revenue forecasts
• Upcoming large expenses

Proactive financial planning can make it easier to respond if economic conditions become more difficult.

So, Is 4.6% Really Worse Than 17%?

The answer depends on how the comparison is measured.

A 4.6% cash rate is obviously much lower than the 17% rates experienced around 1990.

But interest rates alone do not determine mortgage stress.

Modern Australians are dealing with much larger property values and substantially larger mortgage balances relative to income. Recent KPMG analysis found that the household interest burden has reached levels comparable with or above those recorded during the 1989–90 period.

So the more useful comparison is not:

17% vs 4.6%

It is:

How much of household income is being consumed by debt repayments?

That is where the modern mortgage story becomes much more complicated.

Frequently Asked Questions About 4.6% Interest Rates and Mortgage Stress

Was the Australian interest rate really 17% in 1990?

Yes. The RBA cash rate reached 17.5% in 1990, while standard variable housing rates were around 17%.

Why can 4.6% interest rates cause so much mortgage pressure?

Today’s borrowers generally have much larger mortgages relative to their incomes and property prices are substantially higher. A lower interest rate applied to a much larger loan can still result in significant repayments.

Are Australian homeowners worse off than they were in 1990?

It depends on the household. However, recent KPMG analysis shows that Australia’s aggregate household interest burden has reached levels comparable to or above the burden recorded around 1990.

Does a 4.6% RBA cash rate mean my mortgage rate is 4.6%?

No. The RBA cash rate influences borrowing costs across the economy, but your actual mortgage rate depends on your lender, loan product and individual circumstances.

Could higher interest rates cause house prices to fall?

Higher rates can reduce borrowing capacity and buyer demand, which can contribute to downward pressure on property prices. The RBA has noted that housing prices have fallen in most capital cities as financial conditions have tightened.

What can homeowners do if repayments become difficult?

Review your cash flow, understand your loan, speak with your lender early and consider professional financial or accounting advice where appropriate. Acting early can provide more options than waiting until repayments become unmanageable.

Speak With Latitude Accountants

Interest rates are only one part of the financial picture. Understanding how debt, cash flow, tax and borrowing costs interact can help homeowners and business owners make better-informed decisions.

Latitude Accountants helps Australian business owners understand their numbers, manage tax obligations, improve cash flow and plan for changing economic conditions.

Get a free consultation for all ABN holders.

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Disclaimer

This article provides general information and commentary only and does not constitute financial, tax, property, investment or legal advice. Property markets and economic conditions can change, and individual circumstances vary. Speak with a qualified adviser about your own circumstances before making financial or investment decisions.