Mortgage Offset Accounts Explained
An offset account is a transaction account linked to your home loan. The balance in your offset reduces the loan balance on which you're charged interest — saving you interest without locking the money away. It's one of the most powerful, flexible tools in Australian personal finance.
How the Interest Saving Works
Your lender calculates interest on your loan balance minus your offset balance, daily:
On a $600k loan at 6.5%, an $80k offset saves roughly $5,200 per year in interest — with the money remaining fully accessible. That's equivalent to a risk-free, after-tax return of 6.5% on the $80k. No investment can guarantee that.
Offset vs Extra Repayments: The Critical Difference
Both offset and extra repayments save the same interest right now. The difference is what happens to the money and to your future tax position.
| Offset account | Extra repayments | |
|---|---|---|
| Interest saving | Same | Same |
| Money accessible? | ✓ Yes — withdraw anytime | ✗ No (redraw has restrictions) |
| Loan balance | Unchanged | Reduced permanently |
| Future deductibility | Preserved | Reduced — can't recover |
| Tax-free? | Yes — no tax on interest saved | Yes — no tax on interest saved |
| Best for | Investors, uncertain plans | Owner-occupiers, set-and-forget |
Investment property trap: If you make extra repayments on what is currently your home loan, then later rent out the property, your deductible loan balance is permanently lower. You can't borrow back the principal you repaid and claim it as deductible. An offset avoids this entirely — the loan stays at its original balance, all deductible if and when the property becomes an investment.
Tax Benefits of Offset Accounts
The interest you save via an offset account is not counted as taxable income — unlike interest earned in a savings account (which is taxed at your marginal rate). This makes the offset's effective return significantly better than a comparable savings account.
Partial vs Full Offset
Most Australian lenders offer either full offset (100% of your account balance offsets the loan) or partial offset (only a percentage offsets). Always check which type your loan product uses — a partial offset account that only offsets 40% of balances is much less valuable than it appears.
Full offset accounts are standard on variable rate P&I loans from major banks. Fixed rate loans rarely offer offset accounts — this is a significant hidden cost of fixing your rate.
Using Your Salary as an Offset Strategy
The simplest offset strategy: direct your salary into the offset account and pay all expenses from there via card or direct debit. Your salary sits in the offset for days or weeks between arriving and being spent, reducing your daily interest charge. Over a year, this saves an additional $500–$1,500 on a $500k loan depending on your pay cycle and spending timing.
Offset Account Fees
Lenders charge $5–$15/month for offset accounts on many loan products. At a mortgage rate of 6.5%, an offset needs a balance of roughly $1,000–$2,800 to break even on the monthly fee. With any meaningful savings, the offset is cost-effective.
Some lenders (particularly online and smaller banks) include offset accounts with no monthly fee as part of their loan product. When comparing home loans, check whether offset is included and whether it's a full or partial offset.
Model your offset savings
Enter your loan balance and offset balance in the mortgage calculator to see exactly how much interest you save and how it changes your loan term.
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