The Benefits and Risks of an Interest Only Mortgage in Australia

An interest only mortgage can sound like a dream come true—lower repayments, more breathing room, and extra cash flow to perhaps invest elsewhere. In Australia, these loans have become increasingly popular, especially among property investors and first-time buyers looking to manage their budgets. But what exactly are they?

The repayment on your mortgage will always include the interest payable on the amount borrowed, no matter what kind of loan you have. If you have a Principal & Interest loan (P&I), part of your repayment will also be allocated to reducing the balance of the loan.

With an Interest Only loan (IO), your repayments only pay the interest that is due and do not reduce the balance (or the amount you borrowed). As a result, an IO loan can only be obtained for a limited period (usually up to five years). At the end of the IO period, the loan will automatically convert to a P&I loan unless you make an application to extend the IO period. Whether you’re buying your first home, refinancing your mortgage, or exploring investment opportunities, it’s essential to weigh both the benefits and the potential pitfalls of an interest-only loan. The more informed you are, the better decisions you’ll make.

interest only mortgage

What is an Interest Only Mortgage?

An interest only mortgage is exactly what it sounds like—a type of home loan where you only pay the interest on the loan for a set period, usually between 1 to 5 years. Unlike traditional principal and interest mortgages, where each repayment chips away at both the interest and the amount you borrowed (the principal), an interest only mortgage postpones reducing the loan balance until after the interest only period ends. At the end of the IO period, your repayments will increase to cover repayments on both the principal and the interest—so you can expect this increase to be significant. You also need to consider the period left to pay off the principal is reduced, which could drive up your repayment amount even further.

So, why would anyone choose this type of loan? For some, the appeal lies in the short-term flexibility. Lower repayments during the interest only period free up cash that can be used for other financial goals, like saving for renovations, managing unexpected expenses, or even investing in additional properties. First-time buyers may use this strategy to afford homes in competitive areas, hoping their income will grow by the time the loan transitions to principal and interest repayments.

This is particularly attractive in high-value property markets like Sydney and Melbourne, where housing prices can be daunting. Because IO repayments will result in you paying more interest over the term of the loan, this option should only be chosen to fill a requirement that you have—such as maximising your tax advantages with a property investment. They are usually not a wise choice just to make loan repayments more affordable.

Similarly, However, it’s important to understand that the initial savings are temporary. Once the interest only period ends, the jump in repayments can be significant, and if property values don’t increase as expected, the financial benefits may not outweigh the risks.

Before opting for an interest only mortgage, map out a plan for how you’ll manage the higher repayments when the loan transitions.

interest only mortgage

The Benefits of Interest Only Mortgages

Lower Initial Monthly Payments

One of the biggest advantages of an interest only mortgage are the lower monthly payments during the interest only period. By paying just the interest and not the principal, borrowers, you can free up cash flow to manage other financial priorities, incl navigating large expenses, saving for a major purchase, or building an investment portfolio.

For homeowners, lower repayments can offer breathing room during times of financial uncertainty or when starting a new job or business. It allows more flexibility to focus on other financial goals without feeling overburdened by high mortgage repayments.

For property investors, the interest on an investment property debt is usually tax deductible – as long as you follow the ATO rules. It should be noted, however, that owner-occupiers will not receive any tax deduction for interest if you take out an IO loan. Please speak to your accountant or financial planner to discuss if an IO loan is the right option for you. This flexibility can be particularly valuable in high-cost housing markets like Sydney and Melbourne, where property prices are among the highest in Australia. Potentially allowing borrowers to enter these markets with more manageable initial repayments, leaving room for future financial planning.

Top Tip: Use the savings from the lower payments to either create an emergency fund or invest in ways that build long-term financial security. Just be mindful that these benefits only last during the interest only period.

Investment Strategy

Interest only mortgages are a popular tool among property investors looking to maximise their financial strategies. By keeping their monthly repayments lower during the interest only period, investors can maintain better cash flow, which they can leverage for further investments. This approach is often referred to as “gearing,” where the aim is to hold onto properties that appreciate in value over time while minimising short-term expenses.

In markets like Sydney and Melbourne, where property prices are high, an interest only mortgage can make it easier for investors to acquire properties without overstretching their budgets. The extra cash saved on repayments can be reinvested in other properties, stocks, or even used to enhance the existing property to increase its rental yield. This strategy allows investors to build and diversify their portfolios without being tied down by large repayments in the initial years of ownership.

The goal for many is to sell the property later at a higher value, relying on capital gains to offset the loan balance and generate profit. Others prefer to transition into principal and interest repayments once their income or rental returns have grown, ensuring they can manage the higher costs when the interest only period ends.

Tax Advantages

One of the key reasons property investors in Australia opt for interest only mortgages is the potential tax benefits. For investment properties, the interest paid on the loan is generally tax-deductible. This means that during the interest only period, when repayments are lower and consist entirely of interest, investors may be able to  claim those payments as deductions on their taxable income. This can help reduce their overall tax liability while maintaining cash flow.

For example, imagine an investor who owns a rental property in Sydney. If their interest only mortgage incurs $20,000 in interest payments annually, they can claim that amount as a tax deduction. This reduces their taxable income and, depending on their marginal tax rate, could potentially save them thousands of dollars at tax time. By pairing this strategy with the lower initial repayments of an interest only loan, the investor can direct more funds toward other ventures, such as purchasing additional properties or improving their current rental property to attract higher rents.

This potential dual benefit—lower out-of-pocket costs and tax savings—may make interest only mortgages a strategic choice for many investors, especially in the early years of property ownership. However, it’s important to note that these tax advantages only apply to investment properties, not owner-occupied homes, and should be factored into a broader financial plan.

Speak to a tax professional or accountant to fully understand how to maximise tax deductions and ensure compliance with Australian tax laws.

interest only mortgage

The Risks of Interest Only Mortgages

Increased PaymentsOnce I/O Period Finished

One of the biggest risks of an interest only mortgage is the steep increase in repayments that occurs once the interest only period ends. During the interest only phase, borrowers enjoy reduced monthly payments since they’re only covering the loan’s interest. However, when the loan transitions to the principal and interest phase, the borrower must start paying back the loan’s principal as well—often over a shorter remaining loan term. This can cause monthly repayments to increase dramatically, sometimes by hundreds or even thousands of dollars.

For example, if you took out a 30-year mortgage with a 5-year interest only period, the principal must now be repaid over the remaining 25 years. This compresses the repayment timeline and results in much higher payments. For borrowers who haven’t adequately planned for this jump, it can create significant financial strain, especially if their income hasn’t increased or if other financial commitments have arisen during the interest only phase.

This risk is particularly pronounced in a rising interest rate environment. If rates increase by the time the interest only period ends, repayments could rise even further, compounding the financial pressure. For some borrowers, this can lead to difficulty meeting repayments or, in the worst-case scenario, defaulting on the loan.

No Equity Building

One significant drawback of an interest only mortgage is that it doesn’t help build equity in your home. Since you’re only paying the interest on the loan and not reducing the principal, the amount you owe on the property stays the same throughout the interest only period. This can make it difficult to sell or refinance the home if market conditions change, as you won’t have accumulated the equity that would typically come from paying down the loan.

Without equity, if you need to sell, you may not be able to cover your mortgage balance if the property value hasn’t increased sufficiently. Similarly, when you try to refinance, you may find it challenging to qualify for more favourable terms.

Property Market Risk

The property market can be volatile, and if property values fall during or after the interest only period, you could be at risk of negative equity. Negative equity occurs when the outstanding loan balance is greater than the market value of the property. In this case, if you need to sell or refinance, you may not be able to recover the full amount of your mortgage.

For instance, consider a homeowner in Melbourne who purchased a property for $750,000 using an interest only loan. After the interest only period ends, the property’s value drops to $700,000 due to a market downturn. If the loan balance is still $750,000, the homeowner now has negative equity, meaning they owe more than the property is worth. This could make it difficult to sell, refinance, or borrow additional funds, creating a significant financial setback.

Interest Rate Risk

Another risk with interest only loans is the potential for rising interest rates, especially if the loan switches from interest only to principal and interest repayments at the end of the I/O period. If interest rates increase during or after the interest only period, your repayments could rise sharply, leading to potential financial strain. Even a small increase in rates may have a substantial effect on your repayment amounts.

For example, let’s say a homeowner takes out an interest only loan with a rate of 3.5% for the first 5 years. When the loan transitions to principal and interest, the rate increases to 5%. If the loan balance is $500,000, the monthly repayment could increase by over $1,100—an amount that could catch many homeowners off guard.

Case Study

Take the example of Sarah, an investor in Brisbane. She purchased a property for $600,000 with an interest only loan and the expectation that property values would rise. Over the first 5 years, she enjoyed lower repayments, freeing up cash to invest in other properties. However, the market took a downturn, and the property value dropped to $550,000. When her interest only period ended, she found herself in a position where the property’s value didn’t provide enough equity to cover the loan balance. Plus, interest rates had risen from 3% to 4.5%, increasing her monthly repayment by over $1,000. Sarah now faced higher payments, a property worth less than she owed, and no equity to help her refinance or sell without potentially incurring a loss.

This scenario highlights the importance of understanding the risks associated with interest only loans, especially in fluctuating market conditions.

Tip: Keep an eye on interest rate trends and market conditions, and consider building an emergency fund or seeking financial advice to prepare for unexpected changes.

interest only mortgage

Who Should Consider an Interest Only Mortgage?

Interest only mortgages are not for everyone, but they can be a strategic option in specific situations. Let’s explore who might benefit from this type of loan and how it can fit into various financial goals.

Property Investors

Experienced property investors often use interest only mortgages to maximise cash flow, especially in high-value property markets. By paying only the interest during the initial years, investors can keep their out-of-pocket costs lower while focusing on building their property portfolio. This allows them to invest in additional properties or improve existing ones, all while maintaining healthy cash flow.

For instance, investors may use the saved funds to enhance rental yields by renovating properties or paying for additional investment opportunities. Interest only loans may be  particularly beneficial for those with a longer-term strategy, where the focus is on capital gains rather than immediate equity building. However, it’s important that investors have a plan in place to manage the loan transition when it shifts to principal and interest payments.

Homebuyers with Short-Term Plans

For individuals who plan to sell their home in a few years, an interest only mortgage can be a helpful financial tool. During the interest only period, homeowners can enjoy lower monthly payments, allowing them to save for a future deposit on their next property or fund other major life expenses. This option might suit first-time homebuyers or people looking to live in a property temporarily before moving or upgrading.

If the property’s value is expected to increase during the ownership period, the lower payments could offer significant flexibility, while still providing an opportunity to sell at a higher price later on. However, it’s essential to be prepared for the jump in payments once the interest only period ends.

People Expecting Higher Future Income

An interest only mortgage may also be an option for individuals who expect a significant increase in income in the near future. For example, someone who is in the early stages of their career or starting a business may anticipate a salary boost or financial windfall in the next few years. In this case, they may be able to enjoy reduced  payments now, knowing that they will be in a stronger  financial position to handle higher repayments when the loan transitions to principal and interest.

This strategy may  give individuals the flexibility to manage their current budget while preparing for the future. However, it’s important to ensure that income growth is realistic and that there’s a backup plan in case circumstances change.

So it may be worth considering an interest only mortgage if you’re an investor looking to maximise cash flow or a homebuyer with short-term plans, but it’s important to have a clear strategy for managing future repayments. 

If you expect a significant income boost, it can provide flexibility, but be aware of the increase in payments once the interest only period ends. If you’re unsure whether this is the right fit for your financial goals, feel free to connect with me—I’d be happy to help you assess your options and make informed decisions for your situation.

How to Apply for an Interest Only Mortgage in Australia

Applying for an interest only mortgage in Australia involves several key steps. First, you’ll need to ensure you meet the eligibility criteria set by lenders. Typically, this includes having a stable income, a good credit history, and a clear plan for repaying the loan once the interest only period ends. Lenders will also assess your ability to service the loan (both during the I/O period & once the period expires, which means they’ll look at your income, expenses, and existing debts to determine whether you can afford the loan.

When applying, you’ll need to provide supporting documentation, including proof of income (like payslips &  tax returns), identification documents, and details of your current assets and liabilities. The lender will also review the property (valuation) you’re buying or refinancing to ensure it meets their criteria.

Mortgage brokers can play a significant role in supporting you during the process. They have access to a wide range of lenders and loan products, and they can help you navigate the complex application process. A broker can assess your financial situation, identify suitable interest only mortgage products, and help you submit the right paperwork. This helps ensure you’re not only applying for a loan you’re eligible for but also one that aligns with your long-term financial goals.

interest only mortgage

Final Thoughts

In summary, while an interest only mortgage can offer lower initial payments and provide financial flexibility, it’s important to understand the potential risks, such as higher payments after I/O period ends, slower equity growth, and the impact of changing market conditions. Whether you’re a property investor, a homebuyer with short-term plans, or someone expecting a future income boost, this type of loan may potentially be a good fit for your financial strategy. However, it’s essential to consider all factors and be well-prepared for the transition to higher repayments once the interest only period ends.

If you’re considering an interest only mortgage, it’s always a good idea to consult with a mortgage broker to ensure it suits your situation. I can help you navigate the process, assess your options, and find the a solution to suit your needs.

Next Steps

If you need assistance or have any questions about interest only mortgages, or if you’re ready to start your application, don’t hesitate to get in touch. I’m here to help you make informed decisions and guide you through the process. Feel free to reach out today!

Frequently Asked Questions

The main difference is how the repayments are structured.

With a traditional mortgage, you pay both the principal (the amount you borrowed) and the interest each month. Over time, your loan balance decreases. In contrast, with an interest-only mortgage, you only pay the interest for a set period (usually 1-5 years).

The principal remains the same during this time, which means you’re not building equity in the property initially. After the interest-only period ends, you start paying both principal and interest, which increases your monthly repayments.

Yes, interest-only mortgages can be more expensive in the long run.

Since you’re only paying interest for a portion of the loan term, your principal balance remains unchanged for several years. This means you’ll pay more interest overall compared to a traditional mortgage, where the principal reduces with each payment.

After the interest-only period ends, your repayments will also increase, as you’ll start paying down the principal as well.

If you can’t afford the higher payments when the interest-only period ends, you could face financial strain.

Your lender may offer solutions such as extending the interest-only period or refinancing the loan, but this will depend on your specific circumstances and the lender’s policies.

If you’re unable to keep up with payments, you may risk falling into arrears, which could lead to foreclosure in extreme cases. It’s important to plan ahead and ensure you can manage the transition to higher payments.

Yes, you can refinance an interest-only mortgage, either before or after the interest-only period ends. Refinancing allows you to switch to a different loan product or lender, possibly securing a more competitive  interest rate or adjusting the loan terms to suit your needs.

However, refinancing will depend on factors such as your serviceability, credit score, equity in the property, and the current market conditions. It’s a good idea to consult with a mortgage broker to explore refinancing options.

The Australian property market plays a significant role for interest-only mortgage holders. If property values are rising, it can benefit you as the value of your property may increase, and you may be able to build equity. However, if the market drops, it could lead to negative equity (when your mortgage balance is higher than the property’s value). In this case, selling the property or refinancing could become more challenging. It’s crucial to monitor the market and be prepared for potential fluctuations in property values.

Contact me today for personalised advice on mortgage options that align with your financial goals. We’re here to help you navigate the process and find a solution within your best interests.

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Disclaimer: 

This page provides general information only and has been prepared without taking into account your objectives, financial situation, or needs. We recommend that you consider whether it is appropriate for your circumstances and your full financial situation will need to be reviewed prior to acceptance of any offer or product. It does not constitute legal, tax, or financial advice and you should always seek professional advice in relation to your individual circumstances.

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