When to Lock in Rates and When to Split Your Loan

Choosing between fixed and variable rates on your home loan matters more when the purchase itself is already stretching your budget.

The structure you select should reflect how much certainty you need in your repayments and whether you expect to make changes to the loan in the next few years. A variable rate gives you full access to offset accounts and unlimited additional repayments, while a fixed rate locks in your repayment amount regardless of rate movements during the fixed period. A split loan combines both structures on the same property.

Variable Rates and Offset Accounts

A variable rate loan moves in line with market rate changes and allows full flexibility in repayment behaviour. You can link an offset account to reduce the interest charged on your loan balance. The offset account works by holding your salary, savings or rental income in a transaction account that offsets the balance of your home loan for interest calculation purposes. If you hold $30,000 in an offset account against a loan balance of $600,000, you pay interest only on $570,000.

Consider a buyer purchasing an apartment in Clayton with a deposit just above the 20% threshold. The buyer expects to receive a performance bonus in the next six months and prefers the option to deposit that amount without restriction. A variable rate owner occupied home loan with a linked offset provides both the flexibility to make additional payments and the benefit of reducing interest costs on any funds held in the offset account. For buyers with irregular income or those expecting lump sum payments, a variable structure can reduce total interest paid over the life of the loan without locking them into higher ongoing repayments.

The offset account is particularly relevant for Melbourne buyers in suburbs with higher purchase prices, where even modest balances in the offset can lead to measurable reductions in interest over time.

Fixed Rates for Repayment Certainty

A fixed interest rate home loan locks in your repayment amount for a set period, typically between one and five years. Your repayment will not change during that period regardless of whether the market rate rises or falls. This structure suits buyers who prioritise certainty over flexibility, particularly those on a fixed salary or managing other financial commitments alongside the mortgage.

Fixed rates typically come with limitations on additional repayments, often capped at $10,000 to $30,000 per year depending on the lender, and may not offer offset account functionality during the fixed period. If you repay the loan early or refinance before the fixed term ends, break costs may apply. These costs compensate the lender for the difference between the fixed rate on your loan and the current wholesale rate the lender can now earn on that capital.

In our experience, buyers who choose fixed rates tend to be managing multiple financial priorities at once, such as servicing a home loan while covering childcare or private school fees, and cannot absorb unexpected increases in monthly repayments.

Split Loan Structures

A split loan divides your total loan amount into two portions, with one portion on a fixed rate and the other on a variable rate. The split can be structured at any ratio depending on your circumstances, though a 50/50 split is common. Each portion operates independently with its own rate, repayment terms and features.

Splitting allows you to retain access to offset and redraw features on the variable portion while locking in certainty on the fixed portion. You can also stagger the fixed term expiry by splitting into multiple fixed portions with different end dates, which reduces the risk of the entire loan reverting to variable at a single point in time when rates may be unfavourable.

As an example, a buyer purchasing a townhouse in Mulgrave with a loan amount of $700,000 might fix $350,000 for three years and leave $350,000 on a variable rate with offset. The fixed portion provides stable repayments on half the loan, while the variable portion allows additional payments from rental income or savings held in offset. At the end of the three-year fixed term, the buyer can choose to refix that portion, move it to variable, or adjust the split ratio depending on their circumstances and the rate environment at that time.

Split structures require more active management than a single-rate loan, but they offer a middle path for buyers who want some certainty without giving up all flexibility. We regularly see this structure used by buyers in Glen Waverley and surrounding areas where household income includes both salary and variable components such as bonuses or commissions.

When to Apply for Pre-Approval on a Fixed or Split Loan

If you intend to fix all or part of your loan, the rate you lock in is typically set at the time of formal approval, not at pre-approval. Rate lock periods vary by lender, generally ranging from 90 to 120 days from the date the loan is formally approved. If settlement occurs outside that period, the fixed rate may need to be reconfirmed at the prevailing rate.

Pre-approval gives you conditional approval for a loan amount and helps you understand your borrowing capacity before making an offer, but it does not lock in a fixed rate. For buyers purchasing in established areas such as Chadstone or Mount Waverley, where competition can move quickly, having pre-approval in place allows you to act when the right property becomes available, then move to formal approval and rate lock once the contract is signed.

If you are comparing fixed rate options across multiple lenders, the comparison should occur at the formal approval stage rather than during pre-approval, since the rate you receive will depend on your deposit size, loan amount, and the specific loan product selected.

Choosing Between Structures

The decision between fixed, variable and split structures depends on your income pattern, your tolerance for repayment fluctuation, and whether you expect to make additional repayments or access equity in the next few years. A variable rate suits buyers with irregular income or those who want to offset savings against the loan balance. A fixed rate suits buyers who need stable repayments and do not expect to make large additional payments during the fixed term. A split structure suits buyers who want both certainty and flexibility and are comfortable managing two loan portions.

Your broker can model repayment scenarios under each structure and show you how different rate movements would affect your repayment obligation. This modelling should be done using your actual loan amount, deposit and expected settlement date, not generic examples.

If you are refinancing an existing loan, the same principles apply, though you will also need to consider any remaining fixed term on your current loan and whether break costs would apply. Refinancing from a fixed to a variable loan, or adjusting the structure of a split loan, may be worthwhile if the rate saving exceeds the cost of breaking the fixed term, but this calculation should be done with specific figures rather than assumptions. You can explore refinancing options to understand how different structures might reduce your overall interest cost or improve cash flow.

Call one of our team or book an appointment at a time that works for you.

Frequently Asked Questions