Interest-only lowers repayments now. The step-up comes later — and it's bigger than most expect.
For a set period you pay only the interest, so repayments are lower. But the debt doesn't shrink, you pay more interest over the life of the loan, and when it reverts to principal & interest over a shorter remaining term, repayments jump in one step. It's a genuine tool for the right situation — not a saving. Here's the honest picture, including the reversion shock most people underestimate.
The reversion step-up, drawn to scale.
A single loan over its life: a low flat plateau while it's interest-only, then a sharp step up when it switches to principal & interest over the shorter remaining term. The debt is the same size at the switch — it just has fewer years left to be repaid. That's the shock.
Illustrative worked example only, not an offer or a quote: $500,000 loan over a 30-year term, 5-year interest-only period, at an indicative ~6.2% p.a. — bars show the monthly repayment before and after reversion. Figures are rounded and for illustration; your actual repayments depend on your loan amount, rate, term and lender, and are confirmed in writing. Interest-only rates are usually priced above the equivalent principal-and-interest rate, which can make the step larger. Rates are indicative and move with the RBA cash rate.
Three things interest-only does — and one it doesn't.
Repayments cover interest only
For an initial period — commonly up to five years — your minimum repayment covers just the interest charged. It's lower than a principal-and-interest repayment, which frees up cash flow while the period runs.
The balance doesn't reduce
Because you're not paying down principal, the loan balance stays the same unless you make voluntary extra payments. There's no forced equity build — growth relies on the market or your own discipline.
It reverts, and steps up
When the interest-only period ends, the loan switches to principal & interest over the remaining — now shorter — term. The same debt over fewer years means a materially higher repayment, on a fixed date.
Interest-only isn't a saving. It's lower now for more later.
This is the part the headline "lower repayments" hides: because the principal doesn't reduce during the interest-only years, interest is charged on the full balance for longer — so total interest over the life of the loan is higher than an equivalent loan repaid as principal-and-interest from the start. You're trading a lower repayment today for a higher lifetime cost and a step-up later.
That doesn't make it wrong — it makes it a tool for specific situations, not a default for everyone. It can suit investors managing holding costs, an offset-account strategy, or a defined short-term cash-flow need. It rarely suits a borrower whose main goal is to own their home outright as soon as possible. The right answer depends entirely on your circumstances.
General information only, not personal credit, tax or financial advice. Interest-only can increase the total cost of your loan. Any figures shown are indicative and not an offer of credit. Consider your objectives and seek advice before deciding.
Interest-only is a small, closely-watched slice of lending.
It sits near historical lows and is assessed carefully — a legacy of the regulator stepping in when it climbed too far. The history explains why lenders want a clear purpose today.
Sources: APRA Quarterly ADI Property Exposure Statistics — Highlights (June 2024 quarter, the latest precise figure confirmed; refresh to the current quarter before go-live); RBA Financial Stability Review Box B (April 2017) for the ~40% peak; APRA on the 30% interest-only benchmark (introduced March 2017, removed from 1 January 2019) and the separate 10% investor-credit-growth guidance (2014–2018). Interest-only share has stayed near historical lows since.
Rising rates hit interest-only borrowers twice.
The RBA cash rate is 4.35%, having risen +0.75 percentage points across three 2026 increases from its 3.60% trough. For interest-only borrowers, a higher rate lands harder than it does for principal-and-interest borrowers — for two compounding reasons.
- During the interest-only period, you're fully exposed. Your repayment is 100% interest, so a rate rise flows straight through to the whole repayment — there's no shrinking principal to soften it, unlike a P&I loan where part of every repayment is chipping away at the balance.
- The reversion step-up gets bigger, not smaller. When the interest-only period ends, the switch to principal & interest happens at whatever the prevailing rate is then. If rates are higher at reversion, the step-up you were already facing is amplified — a larger balance-per-year repaid at a higher rate, in one jump.
Cash rate 4.35% per the RBA (target effective 17 June 2026). Variable interest-only rates move with the cash rate and lender pricing; the direction and size of any change depends on your lender and loan. Indicative only, not an offer.
A tool for specific cases — not a default for everyone.
Property investors
Lower holding costs free up cash flow, and some investors prefer to keep the deductible investment balance intact while directing surplus cash to non-deductible debt first. Whether that helps depends on your situation — the tax side is for your accountant, not us.
Interest-only plus offset
Some borrowers pair a variable interest-only loan with a linked offset account, parking surplus cash there instead of paying down principal. The offset reduces the interest charged while the funds stay accessible — but it takes discipline to actually save.
A defined cash-flow window
Owner-occupiers sometimes use a short interest-only period to bridge a known, temporary situation — parental leave, a renovation, an income transition. A shorter period keeps the eventual step-up smaller and is usually easier to approve.
Paying off your home fastest
If your priority is owning your home outright as soon as possible, interest-only usually works against you — no principal comes off during the period, and you pay more interest overall. Principal-and-interest is typically the better structure here.
Before you sign: know your reversion figure.
The single most useful thing you can do is find out — in advance — what your repayment becomes after the interest-only period ends, and stress-test your budget against it. Diarise the expiry date and plan 6–12 months ahead: your options at that point are to move to principal & interest, ask your lender about a further interest-only period (a fresh credit assessment, never automatic), or refinance.
We can model the post-reversion repayment with you and compare how different lenders price and assess interest-only, across our panel of 50 lenders. Indicative only; your options depend on your circumstances and are confirmed in writing.
Interest-only loans, answered straight.
How does an interest-only home loan work?
During the interest-only period — commonly up to five years — your minimum repayments cover only the interest charged on the loan. The principal balance stays the same unless you make voluntary extra payments. When the period ends, the loan reverts to principal-and-interest repayments calculated over the remaining, shorter term.
What happens when the interest-only period ends?
The loan reverts to principal-and-interest over the remaining term. Because no principal has been repaid and there are fewer years left, the new repayment is noticeably higher than the interest-only amount. Before expiry you can move to principal-and-interest, ask your lender about a further interest-only period (which is a fresh assessment, not automatic), or refinance to another lender.
Why do repayments jump so much at reversion?
Two reasons compound. First, you start repaying principal as well as interest. Second, the full balance must be repaid over a shorter window — five years interest-only on a 30-year loan leaves 25 years to repay the whole principal. If rates have also risen by then, the step-up is larger again. This is often called repayment shock.
Do I pay more interest overall with interest-only?
Generally yes. Because the principal doesn't reduce during the interest-only period, interest is charged on the full balance for longer, so total interest over the life of the loan is higher than an equivalent principal-and-interest loan. Lower repayments now are traded for a higher lifetime cost — interest-only is not a saving.
Who typically uses interest-only loans?
Property investors are the most common users — lower holding costs free up cash flow, and some direct surplus funds elsewhere. Owner-occupiers sometimes use a short interest-only period for a temporary situation like parental leave or a renovation. Lenders will want the request to make clear sense for your circumstances.
Are interest-only loans harder to get approved?
They can be. Lenders assess you on your ability to meet the higher principal-and-interest repayments that apply after the interest-only period, over the reduced remaining term. Australian regulators have historically scrutinised interest-only lending closely, so lenders typically want a clear purpose and a stronger overall position. Policies vary significantly between lenders.
Is interest-only tax-effective for investors?
It can play a role in some investors' strategies — keeping the investment loan balance, and the interest on it, higher while directing surplus cash elsewhere — but the outcome depends entirely on your circumstances. Tax is not our area: speak to your accountant or a registered tax adviser before choosing a loan structure for tax reasons.
Thinking about interest-only? Let's check the whole picture first.
We'll model what your repayment becomes after reversion, weigh it against principal-and-interest, and compare how lenders price and assess it — so the structure fits your goal, not just this month's cash flow. No credit check to start.
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