Every week, someone walks into a lender's branch, takes the loan structure they are offered, and walks out with a redraw facility when what they actually needed was an offset account. For an owner-occupier who will never invest, this is a minor inconvenience. For anyone who might one day convert their home to an investment property, buy shares, or enter the property market a second time, the wrong structure at the start can permanently compromise their tax position in a way that is difficult and expensive to unwind.
The Surface Similarity
Both offset accounts and redraw facilities let you hold extra money against your mortgage and reduce the interest you pay. On an interest calculation basis, they work identically: if you have a $600,000 home loan and $50,000 sitting in an offset or available as redraw, you pay interest on $550,000, not $600,000. The daily interest calculation is the same either way.
This similarity is why the distinction is so often overlooked. A bank's mobile app will show both features with broadly similar interest-saving projections and similar access - you can transfer money in and out of either. The difference is not visible in day-to-day banking. It only becomes visible when you do something with that money that has a tax consequence.
The Fundamental Structural Difference
An offset account is a separate deposit account - legally distinct from the loan - that is linked to the loan for interest calculation purposes. Money you put into the offset is your money in a bank account. You can deposit and withdraw it freely. Its presence reduces the interest charged on the loan, but it does not change the loan balance itself. The loan balance remains fixed at whatever you originally borrowed, minus your scheduled repayments.
Redraw is different in a fundamental way: when you make extra repayments into a home loan, those payments reduce the actual loan balance. Redraw is the facility to pull those surplus repayments back out. When you redraw, you are not accessing your savings - you are re-borrowing money that was previously lent to you and that you had repaid. You are increasing the loan balance back up.
The key distinction
Offset: your money in a linked account. Redraw: re-borrowing money you already repaid. This legal and structural difference is why the ATO treats them differently when the funds are used for income-producing purposes.
The Tax Difference That Matters
The ATO's rules on deductibility of mortgage interest are clear: interest is deductible only to the extent that the borrowed funds are used for income-producing purposes (see Taxation Ruling TR 2000/2). The purpose test looks at what the borrowed money is actually used for, not the interest rate, the loan account, or the lender.
If you redraw from your home loan to buy shares or a deposit on an investment property, the interest on the redrawn amount is deductible - because those funds are now being used for income-producing purposes. So far, redraw and offset appear equivalent.
The problem arises when the loan has been contaminated. If at any point you made extra repayments into your home loan and then redrawed for a personal purpose - a car, a holiday, renovations - the loan now contains a mixture of deductible and non-deductible debt. A subsequent redraw for investment purposes draws from this mixed pool. The ATO's position is that you cannot simply apportion: once a loan is mixed, the interest must be apportioned across all uses, and establishing the correct deductible proportion requires careful record-keeping that most borrowers have not maintained.
Why Offset Avoids the Contamination Problem
Because an offset account is legally separate from the loan, whatever you do with your offset balance does not affect the loan balance or its purpose. You can pay your salary into the offset, spend from it on everyday expenses, take money out for a holiday, and the home loan itself remains at its original balance with its original purpose intact - to fund the purchase of your home.
When you later want to invest - whether by buying shares with cash from the offset, or by converting your home to an investment property and using the loan for that purpose - the loan's deductibility question is clean. The loan was always used to buy the house. The house is now an investment property. The interest is deductible. The offset transactions are irrelevant to that analysis.
With redraw, if you have ever pulled money back out for personal use and then made further repayments, the history of the loan is the critical question. Many borrowers genuinely cannot reconstruct that history.
Debt Recycling and the Split Loan Structure
The cleanest loan structure for anyone who intends to invest while paying down a home loan is a split facility: one account for the non-deductible home loan (with an offset linked to it), and a separate account for investment borrowing. This is the foundation of debt recycling - the strategy of gradually converting non-deductible home loan debt into deductible investment debt as equity builds.
In the debt recycling structure, the investor makes extra payments into the home loan account, then immediately redraws that same amount into the investment account, which is used to purchase income-producing assets. Each cycle reduces the non-deductible balance and increases the deductible investment balance. The redraw is explicitly for investment - the purpose is unambiguous and documented from the outset. This is a different situation from a mixed-purpose redraw with an opaque history.
Practical guidance
If you are an investor or think you may invest in the future, set your home loan up with an offset account from day one. The annual offset fee - typically $120 to $180 - is trivial relative to the tax position it protects. Redraw is appropriate for straightforward owner-occupiers who will never invest and who want a slightly simpler product. The moment investment enters the picture, offset is the right structure.
Frequently Asked Questions
I already have a redraw facility - can I switch to an offset?
Yes, but not always without cost or disruption. If your current loan does not include an offset account, you may need to refinance to a product that does. Some lenders allow you to add an offset to an existing loan for an annual fee - worth checking before going through a full refinance. The earlier in the loan life you make the switch, the more value you get from the offset structure, particularly if you plan to invest later and want a clean loan history going forward.
Does it matter which account I pay my salary into?
Yes, significantly. Paying your salary directly into your offset account means every dollar reduces the interest-bearing balance from the day it arrives until the day you spend it. Paying into a separate transaction account and transferring periodically loses the daily interest benefit for however long the money sits elsewhere. On a $700,000 loan at 6.5%, routing $8,000 monthly salary through the offset rather than a standard account can save $1,500 to $2,500 in interest over the year.
My lender charges a fee for an offset account - is it worth paying?
In most cases, yes. A typical offset account fee is $10 to $15 per month. On a $700,000 loan at 6.5%, having $50,000 in the offset saves approximately $3,250 in interest annually - versus a fee of $120 to $180. The fee becomes questionable only if you hold very small balances and have no investment plans. If you ever plan to invest, the structural protection the offset provides is worth significantly more than the fee alone.
Want your loan structured correctly from the start?
Michael works with owner-occupiers and investors across south-west Sydney on loan structures that protect future tax positions. Book a free strategy session.
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