Interest Only Home Loan Australia 2026: How It Works

What Is an Interest Only Home Loan?

An interest only home loan is a mortgage where, for a set period, your repayments cover only the interest the lender charges, not the principal (the actual money you borrowed). That period (the interest only period) usually runs 1 to 5 years for owner-occupiers and up to 10 years for investors, with a few lenders stretching to 15. When it ends, the loan rolls over to ordinary principal and interest (P&I) repayments for whatever term is left, and your repayments step up.

Worth saying plainly, because almost no bank page will: an interest-only mortgage is structurally an investor product. It rarely suits an owner-occupier first home buyer, and the reason is the tax treatment, not the marketing. Since 2018, around 40% of new investor lending in Australia has been interest only, against only about 8 to 12% of new owner-occupier lending (RBA, May 2026 Bulletin). That gap isn't an accident. It's the whole story.

The appeal of interest only is obvious. Your monthly repayment is lower because you're not chipping away at the balance, and for a household stretched thin in the early years, freeing up a few hundred dollars a month sounds like breathing room. But it's a deferral, not a discount. The principal doesn't go anywhere; it's waiting for you, in full, on the day the interest only period ends.

Four things to get straight before you go any further:

• Your loan balance doesn't budge. Borrow $500,000 on day one and you'll still owe $500,000 on the last day of the interest only period, even after years of payments.
• You don't pay less overall, you pay more. Because the balance stays large for longer, it racks up more interest across the life of the loan than a P&I loan would.
• Interest only is not a way to borrow more. Lenders work out your serviceability on the eventual P&I repayment, not the lower interest-only figure, so your maximum loan doesn't go up just because the first few years are cheaper.
• It's built for investors. The tax rules (covered further down) make the strategy coherent for an investment property in a way it almost never is for the home you live in.

Whether interest only is right for you comes down to two questions: why are you borrowing, and what's your plan for the day the interest only period ends? For most first home buyers buying a home to live in, the honest answer is "probably not". For investors and rentvestors, it's often "yes". The rest of this guide walks you through that decision with real numbers.

How Do Interest Only Repayments Work?

The easiest way to see how an interest only home loan works is to run the maths on a real loan. Take a $500,000 loan at 6.0% over 25 years. We're using 6.0% as a round illustrative number; current interest-only lows sit a touch under that, around 5.8 to 5.9%, but the round figure keeps the arithmetic clean.

• P&I repayment: about $3,220 a month. Every payment covers the interest and shaves a little off the balance.
• Interest only repayment: about $2,500 a month. That's purely the interest: $500,000 × 6.0% ÷ 12 = $2,500. The balance stays at $500,000 the whole time.
• Cash you free up during the interest only period: roughly $720 a month, or about $8,640 a year.

Nearly nine grand a year back in your pocket. So far it reads like a win. Then the interest only period ends, and the catch arrives.

Say you took 5 years of interest only. You now have to repay the full $500,000 over the 20 years that are left, not the original 25. The P&I repayment on $500,000 at 6.0% over 20 years is about $3,580 a month. Line up the two paths:

• Straight 25-year P&I: $3,220 a month, every month. Total paid over the life of the loan about $966,200.
• 5 years interest only, then 20 years P&I: $2,500 a month for five years, then $3,580 a month for twenty. Total about $1,009,200, about $43,000 more in interest, for the privilege of paying less early on.

The jump from $2,500 to $3,580 is the bit people don't see coming. If your budget was already snug at $2,500, $3,580 is a different conversation entirely. Most interest-only borrowers only feel how steep that step is when they're standing right at the top of it.

The principle underneath all of this: interest only lowers your repayments today by raising them tomorrow, and it costs you more in total interest along the way. It's only worth it when the cash you free up is doing something more valuable than the extra interest it costs, which, for an owner-occupier, it usually isn't.

Interest Only vs Principal and Interest, Which Is Better?

This is the decision that actually matters, and for most people there's a clear answer; it just depends on which kind of borrower you are. Principal and interest vs interest only isn't really a contest of features. It's a question of whether the interest you're paying is tax-deductible. Here's the side-by-side:

The honest version: interest only is an investor product wearing the same name as a home loan. For an investment property, where the interest is deductible and the freed-up cash is being redeployed into other tax-smart structures, the strategy holds together. For an owner-occupier first home buyer paying a non-deductible mortgage on the home they live in, it mostly delays the inevitable and adds tens of thousands in extra interest.

Principal and interest wins for most owner-occupiers because every repayment pulls double duty: it covers the interest and builds equity. That equity is what later lets you refinance to a sharper rate, release a guarantor, or borrow against the place for a renovation. With interest only, none of that happens until the period ends, at which point you're five years older and haven't reduced the balance by a dollar.

Interest Only Home Loan Rates Australia 2026

Interest only home loan rates in Australia are almost always a little higher than the equivalent principal and interest rate, usually by a few tenths of a percent. Lenders treat interest-only loans as marginally riskier: equity builds slowly, and the eventual jump to P&I can tip a stretched borrower into arrears.

Some rough 2026 benchmarks for advertised variable rates (these shift constantly, so always check the live rate with a lender or broker before you bank on it):

• Owner-occupier interest only variable rates start from around 5.9% at the sharpest end of the market, rising to 7%+ with non-conforming lenders (money.com.au, June 2026).
• Investor interest only variable rates start from around 5.8 to 5.9%. Investor lows currently sit close to, and sometimes below, owner-occupier lows, so don't assume one is always cheaper than the other.
• Fixed interest only rates (1 to 5 years) are widely available, and often priced close to the same lender's fixed P&I rate for the same term.

Compare the comparison rate, not the headline rate. The comparison rate is mandated by law and folds in the upfront and ongoing fees, so it's a fairer read on what the loan actually costs. A 5.9% headline with $700 a year in fees can work out dearer than a 6.05% rate with none, and the comparison rate is what catches that.

Two pieces of 2026 regulation are worth having on your radar, because both shape how much you can borrow:

• The RBA cash rate is 4.35% (as of June 2026). Home loan rates move with the cash rate, so check where it sits today rather than planning around an assumed direction of travel (RBA, May 2026).
• APRA's debt-to-income limits are live from 1 February 2026. Banks must now keep new lending to borrowers with a debt-to-income ratio of six or more to around 20% of their new loans, measured separately for owner-occupier and investor books, with new dwellings and owner-occupier bridging loans exempt (APRA). If you're borrowing a large multiple of your income, this can quietly cap what you're offered.

A couple more things to know about interest only rates and eligibility:

• Interest only usually wants an LVR around 80% or lower. If you're buying with a thin deposit, you may not qualify for interest only at all, or you'll be paying lenders mortgage insurance on top, a real catch for first home buyers that bank pages tend to skip (MoneySmart).
• APRA's 2017 interest-only benchmark was wound back (removed from 1 January 2019), but lenders still scrutinise interest only applications more closely than P&I, especially from owner-occupiers.
• Your actual rate depends on your LVR, loan size, credit profile and whether the property is owner-occupied or an investment. The advertised "from" rate is the best case, not the offer you'll get.

Interest Only Loans for Investment Properties

This is where an interest only loan genuinely earns its keep. The tax treatment of an investment property loan changes the maths completely, which is why interest only is so heavily skewed towards investors: since 2018, around 40% of new investor lending has been interest only, against only 8 to 12% of owner-occupier lending (RBA, May 2026 Bulletin).

Why investors lean on it:

• It keeps deductible interest as high as possible. On an investment property, the interest is a deduction against your rental income, and against your salary if the place is negatively geared. Note the May 2026 federal budget change: for established investment properties bought after 12 May 2026, from 1 July 2027 rental losses can no longer be offset against salary (they carry forward against rental income and future capital gains instead), with eligible new builds carved out and existing owners grandfathered. Paying down principal gives you no tax benefit; it just shrinks the deduction. Interest only holds the deductible interest steady.
• It protects cash flow for better uses. The money you're not putting towards principal can go into non-deductible debt instead, your own home loan, say, or into another property or your super.
• It pairs neatly with an offset account. Smart investors run the interest-only investment loan alongside an offset, parking spare cash there rather than paying the loan down. You cut the interest you're charged (same effect as paying down principal) while keeping the cash within reach and the deductible debt intact.

This is the heart of the rentvestor playbook: take an interest only investment loan to keep the deductible interest high, and funnel every spare dollar into the offset or principal of your own home loan, where the interest isn't deductible and every dollar repaid saves real after-tax money. It's why rentvesting and interest only go together; the structure works for an investment property in a way it simply doesn't for the home you live in.

One honest caveat: the tax benefits are real, but they lean on the property actually growing in value. Interest only stretches your exposure to that growth. If prices climb, you've held a bigger asset for longer and ridden the upside; if they fall or flatline, you've paid more interest for less equity. "It's tax deductible" is not a reason to ignore the fundamentals. Our CGT guide covers what happens when you eventually sell.

Should First Home Buyers Get an Interest Only Loan?

The answer most bank and broker pages won't give you straight: for the large majority of first home buyers buying their own home, no. Principal and interest is almost always the better structure, and it's not close.

Why interest only rarely fits a first home buyer:

• The interest isn't deductible. The entire investor case collapses for an owner-occupier; there's no tax benefit to maximising deductible interest, because there's no deduction on the home you live in.
• You lose five years of equity momentum. A P&I borrower builds equity through repayments on top of any capital growth. An interest-only borrower only builds equity if the property rises. Flat market plus interest only equals no equity gained in five years.
• Payment shock lands hardest on people least ready for it. First home buyers take interest only for "cash-flow reasons", and those reasons are usually still there five years on. The jump from $2,500 to $3,580 a month doesn't land any softer because you've been stretched the whole time.
• Your total interest bill is bigger. On the $500K example above, interest-only-then-P&I costs about $43,000 more in total interest. That's real after-tax money, not a deduction.

When interest only can stack up for a first home buyer:

• You're taking extended parental leave or a short, defined income dip (a year or two), and you've actually budgeted for the repayment jump that follows.
• You're rentvesting rather than living in the place; interest only is genuinely the right call on an investment loan.
• You're running a disciplined offset strategy: paying the interest-only minimum, but funnelling the difference (and everything else) into an offset for flexibility.
• You have a clear, time-limited reason for wanting the cash flow now, and a written plan for the switch back to P&I.

When it's a mistake:

• You can only just afford the interest-only repayment. "We can barely manage the lower payment" is the single loudest warning sign there is.
• You're hoping it lets you borrow more. It doesn't; lenders assess you on the eventual P&I, so the trick simply fails.
• Your plan for the interest only period ending is "we'll deal with it then".
• You're buying to stay put for the long haul. You're just postponing the cliff.

Before you choose interest only, run both scenarios with your real numbers in our mortgage repayment calculator, and use the borrowing power calculator to check you can actually service the eventual P&I repayment, not just the cheaper introductory amount.

What Happens When the Interest Only Period Ends?

The end of the interest only period is the most under-discussed part of the whole structure, and the part lenders are slowest to spell out. You sign up, enjoy the lower repayments, and then a letter lands three to six months out telling you exactly how much your repayments are about to climb.

What happens on its own: your lender writes to you, usually three to six months before the interest only period expires, confirming the loan will convert to P&I on the roll-over date. The new repayment is worked out on the remaining balance, still the full original principal, spread across the remaining term. You don't have to do anything; it just switches.

Why the repayment jumps so much, typically around 30 to 50%:

• You now have to repay the full principal over a shorter remaining term.
• A 25-year loan that opened as five years interest only becomes a 20-year P&I loan.
• You do pay a little less total interest from here on (P&I rather than interest only), but the monthly number is higher.

It's worth keeping this in proportion: the RBA has noted that most borrowers managed the transition from interest only to P&I reasonably well when the wave of conversions hit in earlier years. The cliff is real, but it's survivable, provided you've planned for it rather than been ambushed by it.

Your options as the date approaches:

• Let it convert to P&I. The default. Do nothing and this happens, so build the higher repayment into your budget well ahead of time.
• Ask to extend the interest only period. Some lenders will, if you reapply and make the case (easier on investment loans). Expect fresh income checks and a new valuation. You can't extend forever; most cap total interest only at 5 years for owner-occupiers and 10 for investors, with a handful going to 15.
• Refinance to a fresh interest only loan elsewhere. A few borrowers restart the clock by switching lenders. It's doable but pricey (discharge, application and valuation fees) and it pushes the principal even further down the road.
• Refinance to P&I at a better rate. If rates have moved, the switch is also a chance to renegotiate. Our refinancing home loan guide walks through the process, and a broker can show you what's on offer.

Start planning 6 to 12 months out. Drop the new repayment into your budget, check it's genuinely affordable, and decide whether to let it convert, extend, or refinance. If affordability is looking tight, talk to a broker early; your options narrow fast once you're inside 60 days of the roll-over.

Pros and Cons of Interest Only Home Loans

The trade-offs, boiled down.

What's in its favour:

• Lower monthly repayments during the interest only period, usually 20 to 30% below P&I.
• Cash-flow flexibility when you have a genuine, time-limited need, like parental leave or getting a business off the ground.
• Real tax benefits on investment loans, especially paired with an offset account.
• The freed-up cash can go to non-deductible debt (your own home), an offset, or other investments.
• A useful tool for rentvestors running a deliberate, tax-aware structure.

What works against it:

• No principal reduction; you finish the interest only period owing exactly what you started with.
• No equity from repayments; only capital growth adds to your stake.
• More total interest over the life of the loan, tens of thousands more on a typical first-home loan.
• Payment shock of around 30 to 50% when the period ends, the riskiest feature of the lot.
• Usually a slightly higher rate than the equivalent P&I.
• Less of a buffer against negative equity if prices fall, since the balance never shrank.
• Tighter lender scrutiny, particularly on owner-occupier applications.

Want the exact difference for your own loan? Our mortgage repayment calculator puts interest only and P&I side by side, and our fixed vs variable home loan guide helps with the next decision once you've settled on a structure.

Frequently Asked Questions

What is an interest only home loan?

An interest only home loan is a mortgage where, for a set period, you pay only the interest the lender charges, not the principal you borrowed. That interest only period is usually 1 to 5 years for owner-occupiers and up to 10 years for investors (a few lenders go to 15). When it ends, the loan converts to principal and interest, and your repayments rise as you start paying the balance down over the remaining term.

How does an interest only home loan work?

While the interest only period runs, your repayment covers only the interest, so the loan balance stays exactly where it started. On a $500,000 loan at 6.0%, that's $500,000 × 6.0% ÷ 12 = about $2,500 a month, against around $3,220 for principal and interest. The lower payment frees up cash, but the principal is untouched, so when the period ends you repay the full balance over a shorter remaining term and the monthly repayment jumps.

How much cheaper are interest only repayments?

Interest only repayments are usually 20 to 30% lower than the equivalent P&I repayment. On a $500,000 loan at 6.0% over 25 years, interest only is roughly $2,500 a month against about $3,220 for P&I, a saving of around $720 a month while the interest only period lasts. But it reverses once the period ends: repayments climb to around $3,580 a month as you repay the full principal over the remaining 20 years.

What's the difference between interest only and principal and interest?

Interest only means you pay only the interest, so the balance doesn't move. Principal and interest means each repayment covers the interest and chips away at the balance. Over time, P&I builds equity through repayments, while interest only only builds equity if the property's value rises. P&I costs less in total interest and has no payment shock, but the repayments are higher from day one. Interest only is cheaper monthly for a while, then jumps when the period ends, and costs more in total interest overall.

Are interest only loans good for first home buyers?

For most first home buyers buying their own home, no. Principal and interest builds equity faster, costs less in total interest, and avoids the payment shock. The investor case for interest only, maximising tax-deductible interest, doesn't apply, because interest on the home you live in isn't deductible. It can make sense in narrow situations: if you're rentvesting (buying an investment), if you're on time-limited leave with a clear plan for the payment jump, or if you're running a disciplined offset strategy. For everyone else, P&I is the safer and cheaper choice.

What happens when the interest only period ends?

When the interest only period ends, the loan automatically converts to principal and interest for the rest of the term, and your repayments typically jump around 30 to 50% because you now repay the full principal over a shorter remaining term (say 20 years instead of 25). This is payment shock. Your options are to let it convert to P&I (the default), reapply to extend the interest only period with your current lender, or refinance to a new loan elsewhere. Start planning 6 to 12 months out, as options narrow quickly once you're within 60 days of the roll-over.

Can I switch from interest only to principal and interest early?

Yes, and it's usually free and often the smart move. You can ask your lender to convert from interest only to principal and interest at any time, and plenty of borrowers do exactly that once the reason for the lower repayments has passed (parental leave ends, income recovers, the investment cash-flow strategy changes). Switching early starts reducing the principal sooner, builds equity, and trims your total interest bill. If you're heading the other way, asking to change an existing P&I loan to interest only, lenders treat that as a credit change and will reassess your serviceability, so it's not automatic.

Can I switch my existing loan to interest only?

Sometimes, but it isn't automatic. Changing an existing principal and interest loan to interest only is a credit change, so your lender will reassess your application much like a new loan: income, expenses, LVR (usually 80% or lower) and your reason for switching. It's most readily approved on investment loans and for borrowers with a genuine, time-limited cash-flow need. Expect the interest only period to be capped (commonly 5 years for owner-occupiers, up to 10 for investors), and remember the repayment will jump again when that new period ends.

Does interest only let me borrow more?

No. This is a common myth, and it's worth being clear about: lenders assess your serviceability on the eventual principal and interest repayment, not the lower interest-only amount. So choosing interest only does not raise your maximum loan. The only thing it changes is your cash flow in the early years, not how much the bank will lend you.

Can I get an interest only loan as an owner-occupier?

Yes, but with tighter conditions than investors get. Owner-occupier interest only is generally capped at a 5-year period, against up to 10 years for investment loans, though there are exceptions: AMP Bank launched a 10-year owner-occupier interest only loan with no mid-term reassessment in May 2025, the first of its kind in Australia. Lenders also scrutinise owner-occupier interest only applications more closely, want to understand why you need it, and check you can service the eventual P&I, not just the interest-only amount. The 2017 APRA restrictions were wound back, but most lenders stay cautious here.

Are interest only home loan rates higher?

Usually, yes. Interest only rates tend to run a few tenths of a percent above the equivalent principal and interest rate from the same lender, because lenders see interest only as marginally riskier; equity builds slowly and the eventual jump to P&I can trigger arrears. In mid-2026, owner-occupier interest only variable rates start from around 5.9% and investor interest only rates from around 5.8 to 5.9%, with investor lows sometimes sitting below owner-occupier lows. Always compare the comparison rate, not the headline rate, as it includes fees and gives a truer cost.

Is interest on an investment loan tax deductible?

Yes. Interest on an investment home loan is deductible against your rental income, and against your salary too if the property is negatively geared. From 1 July 2027, for established investment properties bought after 12 May 2026, that salary offset no longer applies (losses carry forward against rental income and future capital gains), with eligible new builds exempt and existing owners grandfathered. That's the main reason interest only is so common among investors; since 2018, around 40% of new investor lending has been interest only, versus only 8 to 12% of owner-occupier lending (RBA), because interest only keeps the deductible interest as high as possible for as long as possible. Interest on an owner-occupier loan is not deductible, which is exactly why the investor case for interest only doesn't carry over to the home you live in. Always check your own situation with a tax professional before structuring a loan for tax reasons.