An offset account is a transaction account linked to your home loan. Every dollar in the offset account reduces the loan balance on which interest is calculated, not the loan balance itself. If your loan balance is $500,000 and you have $60,000 in an offset account, you pay interest only on $440,000.
This is one of the most financially efficient features of an Australian home loan, and understanding how to use it correctly produces real, measurable savings.
Interest on a home loan accrues daily on the outstanding balance. An offset account reduces that daily balance, which reduces the daily interest charge, which reduces how much of each minimum repayment goes toward interest rather than principal. Over time, this means you pay the loan off faster and pay less total interest.
The saving equals: (average daily offset balance) × (loan interest rate) × (number of days). This is structurally equivalent to earning a return equal to your mortgage interest rate on the money sitting in the offset account, tax-free, because it reduces a cost rather than generating income.
| Offset balance | Loan balance | Rate 6% | Annual interest saving |
|---|---|---|---|
| $20,000 | $600,000 | 6% | $1,200 |
| $50,000 | $600,000 | 6% | $3,000 |
| $100,000 | $600,000 | 6% | $6,000 |
| $50,000 | $600,000 | 7.5% | $3,750 |
The effective return on money in an offset account equals your mortgage interest rate. At a 6.5% rate, $50,000 in your offset earns a guaranteed, risk-free 6.5% effective return, tax-free. No Australian savings account currently beats this for people with a mortgage.
Both offset accounts and redraw facilities reduce the interest you pay, and both let you access the money later. The difference is structural and has tax consequences for investors.
Money in an offset account remains your money in a separate account. You can withdraw it at any time without formal process and without affecting your loan terms. The money was never actually paid into the loan.
Money in a redraw facility has been paid into the loan as extra repayments. Redrawing it involves formally drawing money back out of the loan. For investment properties, redrawing money and spending it on personal expenses is not tax-deductible — it breaks the nexus between the borrowing and the income-producing purpose. An offset account avoids this issue because the money was never mixed with the loan.
For investment property owners or people who may rent their home out in the future, an offset account is almost always better than redraw, specifically because of this tax treatment.
Variable rate home loans that include a full offset account typically charge an annual package fee of $300 to $400 per year compared to basic variable loans with no offset. Whether the fee is worth paying depends on your average offset balance.
At a 6% interest rate, an offset account needs an average balance of at least $5,000 to $7,000 to cover a $350 annual fee. Most households with any savings, salary credits, or emergency fund in the offset account exceed this easily. For someone maintaining $20,000 to $50,000 in the offset, the annual saving vastly exceeds the fee.
The maths changes for smaller balances. If you consistently carry less than $5,000 in the account, a basic variable loan at a lower rate may produce a better outcome than a package loan with offset at a higher rate. Check the comparison rate — it factors in the annual fee.
Put all income through the offset. Have your salary credited directly to the offset account, not a separate transaction account. Every day your salary sits in the offset before being spent is a day of reduced interest.
Use a credit card for day-to-day spending. Put all monthly expenses on a credit card and pay the balance in full on the due date. This keeps more cash in the offset for longer during the month. The benefit only works if you pay the card in full every month — any interest on the card will more than offset the mortgage saving.
Keep your emergency fund in the offset. If you have savings earmarked for emergencies sitting in a separate account, moving them to the offset earns the mortgage interest rate rather than a deposit rate, with the same accessibility.
Some loans offer a "partial offset" where only a percentage of the offset balance reduces the loan balance — for example, 50% or 40% offset. These are almost always a worse deal than a full offset and should be checked carefully before accepting. The product is marketed as an offset but the effective return is materially lower.
Most fixed rate loans do not include a full offset account. A small number of lenders offer fixed rate loans with offset, but they are rare and typically require a premium. If offset functionality is important to you, a fixed rate mortgage usually means forgoing it.
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