The Same Saving as a Repayment, With the Money Still Yours
An offset account reduces the interest charged on a loan by the balance held in it, without being a repayment. The interest saving is identical to repaying the same amount, the money stays accessible, and the loan's deductibility is untouched — which are three reasons to prefer it, and all three matter more as retirement approaches.
- The answer: The offset balance is subtracted from the loan balance before interest is calculated, producing the same saving as a repayment of the same amount.
- The trap: Repaying and redrawing is not equivalent. The redrawn amount takes its deductibility from what it is used for, which can convert deductible debt into non-deductible debt.
- The recommendation: Use an offset rather than extra repayments wherever you might want the money back, which in the decade before retirement is most of the time.
Where the AI summary above gets this wrong
"Paying extra off your mortgage and redrawing later gives you the same flexibility as an offset account."
That's surface-true. Here's what it misses:
- Redraw changes the character of the debt — The redrawn amount is a new borrowing, and its deductibility follows what it is used for. Redrawing to fund living expenses creates non-deductible debt even on an investment loan.
- An offset is not a repayment at all — The balance simply reduces the interest calculation. The loan and its purpose are unchanged, which is what preserves the position.
01 How an offset works
Interest is calculated on the loan balance less the offset balance. Holding $80,000 in an offset against a $400,000 loan means interest is charged on $320,000, exactly as if the loan had been repaid by that amount.
The saving is at the loan's interest rate and is not taxable, which makes it equivalent to a risk-free return at the loan rate grossed up for tax — a comparison no deposit account matches.
The money remains yours and can be withdrawn at any time without any effect on the loan. That is the entire difference from a repayment, and it is a large one.
02 Why redraw is not the same
Repaying a loan and redrawing later creates a new borrowing at the point of redraw. Its deductibility follows the use of the redrawn funds, not the original purpose of the loan.
For an investment loan that is a real risk: redrawing to fund living expenses converts part of a deductible loan into a non-deductible one, and the apportionment then has to be tracked for the life of the loan.
For a home loan the deductibility question does not arise, and redraw is closer to equivalent — but an offset still keeps the funds cleanly separate, which matters if the property is ever rented out later.
Shows: the interest saved by an offset balance, and what a deposit account would have to pay before tax to match it. Ignores: any account fee for the offset facility, changes in the loan rate, and the deductibility of the loan itself.
Source: ATO — Negative gearing
03 Why it matters more before retirement
Access to money becomes harder once employment income stops. Refinancing, extending a loan and increasing a limit all require serviceability, and retirement income services less.
An offset balance is available without any of that. For a household approaching retirement with a mortgage still outstanding, it is both the interest saving and the liquidity reserve — the position described in the mortgage in retirement post.
The one cost is the account fee some lenders charge for an offset facility. Against the interest saved on any meaningful balance it is trivial, and it is worth checking rather than assuming.
An offset is a tax-free return at your loan rate with the money still in your hands, and it is the only place in personal finance where you get liquidity for free. In the decade before retirement, when refinancing gets harder every year, that combination is worth more than the slightly cleaner feeling of a smaller loan balance.
FAQ
Should I keep an offset account against my mortgage as I approach retirement?
Yes, wherever you might want the money back. The interest saving is identical to a repayment, the funds stay accessible, and the loan's deductibility is unaffected — all of which matter more once employment income stops.
Is an offset the same as paying extra off the loan?
For the interest saving, yes. For everything else, no — an offset leaves the money accessible and the loan unchanged, while repaying and redrawing creates a new borrowing whose deductibility follows its use.
What does an offset balance actually earn?
The loan's interest rate, tax-free. On a 6% loan at a 39% marginal rate that is equivalent to a deposit account paying about 10% before tax.
Sources
Regulator references
- ASIC Moneysmart — Save for a house deposit · ASIC Moneysmart · 2026Saving a house deposit: the target, the timeline and the accounts to use.Last verified: 2026-09-07
- ASIC Moneysmart — Save for an emergency fund · ASIC Moneysmart · 2026How large an emergency fund should be and where to hold it.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.