An offset account is one of the most powerful tools available to Australian mortgage holders — yet most people significantly underestimate how much it saves. Our calculator shows exactly how your offset balance reduces your interest and cuts years off your loan.
Open the full mortgage calculator with offset account modelling and debt-free date
Open offset calculator →Based on a $600,000 loan at 6.5% over 30 years — adjust for your loan in the calculator above.
| Offset balance | Interest saved | Years cut | Effective interest rate |
|---|---|---|---|
| $10,000 | ~$23,700 | ~0.7 years | ~6.1% |
| $25,000 | ~$59,000 | ~1.8 years | ~5.95% |
| $50,000 | ~$118,000 | ~4 years | ~5.7% |
| $75,000 | ~$177,000 | ~6.5 years | ~5.45% |
| $100,000 | ~$236,000 | ~8 years | ~5.2% |
| $150,000 | ~$330,000 | ~13 years | ~4.7% |
Adding to your offset each month creates a compounding effect — the balance grows, more interest is offset each month, and more of your fixed repayment goes to principal. Here is what consistent monthly contributions do to a $600,000 loan at 6.5% starting with zero offset balance:
An offset account is a standard transaction account linked to your home loan. Every dollar sitting in the account reduces the loan balance that interest is calculated on — dollar for dollar, every day.
Your minimum monthly repayment stays the same. The difference is that with less interest to cover, more of each repayment chips away at the principal. This accelerates the rate at which your loan reduces, saving substantial interest over the life of the loan.
Critically, the money never leaves your control. Unlike making extra repayments, you can transfer funds out of an offset account anytime. This makes it an ideal place to park your emergency fund, savings, and any lump sums you receive — they all work hard reducing your interest while remaining fully accessible.
The most effective way to maximise your offset account is to have your entire salary deposited directly into it on payday. You then use a credit card for all day-to-day spending (groceries, petrol, bills, subscriptions) and pay the card off in full each month.
This keeps the maximum possible balance in your offset for the maximum number of days each month. Even a few extra thousand dollars sitting in the offset for an extra week or two per month adds up significantly over 30 years. The credit card strategy is free — it costs nothing as long as you never pay interest on it — and can be worth tens of thousands of dollars over the life of a loan.
Both offset accounts and redraw facilities allow you to access extra money you have put toward your loan, but they work differently. An offset account is a separate transaction account — your money never technically enters the loan. A redraw facility holds extra repayments inside the loan itself, which you can withdraw later.
For most owner-occupiers the practical difference is minor, but there are important distinctions: offset account funds are more accessible (instant transfer), while redraw can sometimes have restrictions or fees. For investment properties, offset accounts have a tax advantage — if you withdraw from redraw to buy an investment, the interest may not be fully deductible, whereas offset funds are always your personal money.
Your offset balance is subtracted from your loan balance before interest is charged each month. If you have a $600,000 loan and $50,000 in your offset, interest is only charged on $550,000. Your repayment stays fixed, but more of it goes to principal each month, paying the loan off faster.
For most Australian home owners with a variable rate loan, yes — especially if you can maintain a meaningful balance. The interest saving is equivalent to earning your mortgage rate (currently ~6.5%) on those funds, tax-free. That outperforms most savings accounts after tax. The main cost is that some lenders charge slightly higher rates or fees for loans with offset facilities — check whether the saving outweighs any extra cost on your specific loan.
Many Australian lenders now allow multiple offset accounts linked to the same loan. This is useful for budgeting — you can separate funds into different buckets (emergency fund, holiday savings, renovation fund) while all of them reduce your mortgage interest. Check with your lender for the specifics of their offset arrangements.
No — your minimum monthly repayment stays the same. The offset reduces the interest charged, meaning more of your fixed repayment goes to principal. This pays off the loan faster but does not reduce the payment amount you owe each month.
Most fixed rate loans do not allow a full offset account. Some lenders offer a partial offset (capped at a certain balance) on fixed loans. If you fix your rate and lose access to your offset, you lose the interest-saving benefit on those funds for the fixed period. This is an important consideration when deciding whether to fix your rate.
Only when your offset balance equals or exceeds your remaining loan balance — at that point you can clear the loan entirely and become debt free. There is no benefit to making partial lump-sum repayments from your offset into the loan, as the interest saving is identical whether the money sits in the offset or reduces the principal. Keep it in the offset where it remains accessible until you can clear the whole thing.