Most lenders won't let you link an offset account to a fixed rate home loan.
That limitation catches many property investors off guard when they're comparing home loan options. You can lock in certainty on your interest rate, or you can reduce your interest through an offset account, but pairing the two isn't usually on the table. For investors holding substantial cash reserves or managing rental income, that creates a genuine trade-off worth working through before you apply for a home loan.
Why Offset Accounts Don't Typically Work With Fixed Rates
Lenders price fixed interest rate home loans based on wholesale funding costs that assume a set repayment schedule over the fixed period. An offset account reduces the interest you pay without changing the loan balance, which disrupts that calculation. When you offset $50,000 against a $500,000 loan, you're only paying interest on $450,000, but the lender still needs to fund the full amount. That mismatch is why most lenders reserve offset functionality for variable rate products.
Some lenders do offer partial offsets on fixed loans, usually capped at a percentage of the loan amount or limited to certain loan products. In our experience, these arrangements come with higher fixed interest rates that remove much of the benefit, particularly when you calculate home loan repayments over the life of the loan.
The Split Loan Approach for Investment Properties
A split loan divides your borrowing between fixed and variable portions, each with separate loan accounts. Consider an investor who purchases a property in Sunnybank Hills for $650,000 with a 20% deposit. They borrow $520,000 and split it as $260,000 fixed for three years and $260,000 variable with a linked offset account.
Rental income of around $550 per week accumulates in the offset account, reducing interest charges on the variable portion while the fixed portion provides protection if variable interest rates rise. Over a three-year period at current home loan rates, that offset balance might average $30,000 once you account for withdrawals for maintenance and other investment costs, which reduces the taxable interest on the variable half of the loan.
This structure also preserves flexibility. If you need to access funds for another deposit or unexpected repairs, you withdraw from the offset rather than breaking a fixed rate home loan early and triggering break costs.
When Full Offset Makes More Sense Than Fixing
Some investors hold significant cash reserves that would sit in an offset account. If you're carrying $100,000 in available funds against a $500,000 investment loan, the interest saved on that offset balance often exceeds the rate difference between fixed and variable products.
You can compare rates across variable home loan options with full offset access from banks and lenders across Australia, but the calculation depends on how long that cash stays in the account. If you're planning to use those funds within six months for another property deposit, the offset benefit won't compound long enough to outweigh a lower fixed interest rate.
Interest Only Loans and Offset Timing
Most property investors choose interest only repayments during the initial years to improve cash flow and build equity in other properties. When you pair interest only with an offset account on the variable portion of a split loan, rental income reduces your interest charges without forcing principal repayments you don't want to make yet.
Consider a scenario where an investor in Parkinson holds a $480,000 loan split evenly between fixed interest only and variable interest only with offset. The fixed portion costs roughly $1,800 per month in interest payments. The variable portion would cost the same, but with $40,000 sitting in the offset account, the actual interest charged drops to around $1,600. That difference accumulates over time without affecting the loan amount or changing your ability to claim interest as a tax deduction.
The offset balance doesn't reduce your principal, so your loan to value ratio (LVR) stays the same, which matters if you're planning to use equity from this property to fund another purchase. You're reducing costs without reducing leverage.
Break Costs and Your Fixed Portion
If you sell the investment property or want to refinance before the fixed period ends, you'll likely face break costs on the fixed portion. These costs reflect the difference between the rate you locked in and the rate the lender can now charge on a new fixed loan for the remaining period.
Break costs can run into thousands of dollars if rates have fallen since you fixed, but they're minimal or zero if rates have risen. The variable portion with offset can be repaid or refinanced anytime without penalty, which is another reason many investors keep at least half their borrowing on variable terms. You're not locked into the entire loan structure if your circumstances or the property market shift.
You can read more about how this calculation works and when break costs apply on our fixed rate expiry page, particularly if you're approaching the end of a fixed term and weighing your options.
Choosing Your Split Percentage
There's no standard formula for how much to fix versus hold on variable with offset. Some investors split evenly, others fix 70% for rate certainty and keep 30% variable for flexibility and offset access. The right mix depends on how much cash you expect to hold in the offset account and how sensitive your cash flow is to rate movements.
An investor with steady rental income and minimal cash reserves might fix 80% to lock in predictable repayments and keep 20% variable just to maintain some flexibility. An investor who regularly moves cash between properties or holds large balances might reverse that, fixing only 30% and keeping the majority on variable to maximise offset benefits.
Your borrowing capacity calculation with most lenders will use the higher of the fixed or variable rate when assessing your ability to service the loan, so the split percentage doesn't usually impact how much you can borrow. It does impact your actual repayments and your ability to reduce interest through offset.
Portable Loans and Future Purchases
If you plan to sell the investment property and buy another within a short timeframe, a portable loan feature lets you transfer the fixed rate to the new property without paying break costs. Not all lenders offer this, and those that do often require the new loan amount to match or exceed the existing balance.
Portability works when you're selling a property in Browns Plains and buying in Calamvale within the same settlement period, but it's less useful if there's a gap of several months or if the new purchase requires a different loan amount. The variable portion with offset transfers more readily because there's no fixed term to preserve.
For investors building a portfolio, keeping loan structures that move with you matters more than chasing the lowest rate on a single property.
Call one of our team or book an appointment at a time that works for you. We'll look at your cash flow patterns, your plans for the next few years, and whether a split structure with offset on the variable portion suits your situation, or if another approach makes more sense for what you're trying to achieve.
Frequently Asked Questions
Can I link an offset account to a fixed rate home loan?
Most lenders don't offer offset accounts on fixed rate home loans because the offset reduces interest payments in ways that conflict with how lenders fund fixed rates. Some lenders provide partial offset on fixed loans, but these typically come with higher rates that reduce the benefit.
What is a split loan and how does it work for investors?
A split loan divides your borrowing between fixed and variable portions, each with separate accounts. Investors often fix part of the loan for rate certainty and keep the rest variable with an offset account linked to it, allowing rental income to reduce interest charges on the variable portion.
How do break costs work if I need to exit a fixed rate loan early?
Break costs reflect the difference between your locked-in rate and the rate the lender can charge on a new fixed loan for the remaining period. If rates have fallen since you fixed, break costs can be substantial, but if rates have risen, costs are minimal or zero.
Should I fix more or less of my investment loan?
The right split depends on how much cash you'll hold in an offset account and how sensitive your cash flow is to rate movements. Investors with large offset balances often keep more on variable to maximise interest savings, while those wanting payment certainty might fix a larger portion.
Does a split loan affect how much I can borrow?
Most lenders assess your borrowing capacity using the higher of the fixed or variable rate, so the split percentage doesn't usually change how much you can borrow. It does affect your actual repayments and your ability to reduce interest through an offset account.
