What are Interest Rates and Borrowing Capacity?

A rise in interest rates reduces how much you can borrow, while a drop can increase your borrowing capacity by thousands of dollars. Lenders assess your ability to repay at the loan rate plus a buffer, so even a small rate movement changes the maximum loan amount they will approve.

How Lenders Calculate What You Can Borrow

Lenders assess your borrowing capacity by measuring your income against all your expenses, including the proposed loan repayment. The proposed repayment is calculated at the interest rate you will pay, plus a buffer of around 2.5% to 3%, to ensure you can still meet repayments if rates rise. When interest rates increase, this assessment rate also increases, which means your maximum borrowing capacity falls.

Consider a buyer in Truganina who earns $90,000 per year with minimal other debts. At a variable rate plus buffer totalling around 8.5%, they might be approved for a loan of around $460,000. If rates rise by 0.5%, pushing the assessment rate to 9%, the same borrower could see their borrowing capacity drop by roughly $20,000 to $25,000. This can make the difference between being able to purchase a property or needing to wait and save a larger deposit.

The buffer is applied regardless of whether you choose a fixed rate or variable rate, because lenders must ensure you can afford the repayment once any fixed period ends. This is why understanding the impact of the assessment rate is important, even if the advertised rate looks attractive.

The Relationship Between Rates and Property Affordability

When rates drop, your borrowing capacity increases because the repayment at the lower assessment rate is smaller relative to your income. This creates more room in your budget and allows lenders to approve a larger loan amount. For buyers in growth areas like Truganina, where demand has remained steady due to proximity to employment hubs and transport links along the Princes Freeway, this can mean access to a wider range of properties without needing to increase your deposit.

The reverse is also true. Rising rates shrink borrowing capacity, which can push buyers toward lower-priced properties or smaller dwellings. In suburbs where the entry point has risen over recent years, this rate sensitivity becomes more pronounced. Buyers who were previously comfortable borrowing at the suburb median may find themselves priced out unless they adjust their deposit or search parameters.

Fixed Versus Variable Rates and Borrowing Power

Your choice between a fixed interest rate and a variable interest rate does not change your initial borrowing capacity, but it does affect your repayment certainty. A fixed interest rate home loan locks your repayment amount for a set period, usually between one and five years, which can help with budgeting if you are concerned about rate rises. A variable rate moves with the market, which means your repayment can go up or down depending on lender decisions and Reserve Bank movements.

Some borrowers choose a split loan, where part of the loan is fixed and part is variable. This approach provides some repayment stability while retaining access to features like an offset account on the variable portion, which can help you build equity faster. However, splitting the loan does not increase your borrowing capacity at the time of application. Lenders still assess your ability to repay based on the higher assessment rate, regardless of how the loan is structured.

In our experience, buyers who expect rates to rise often favour a fixed rate for the security it provides, while those who want flexibility and the ability to make extra repayments without penalty lean toward a variable rate. Both strategies are valid depending on your circumstances and risk tolerance.

How Rate Discounts Affect Your Loan Amount

Many lenders offer rate discounts off their standard variable rate, particularly for owner-occupied borrowers with a lower loan to value ratio. A discount of 0.5% to 1% can reduce your monthly repayment, but it does not usually increase your borrowing capacity at the application stage because lenders still apply the same buffer when calculating what you can afford.

Where rate discounts do matter is in your ongoing repayment. A lower rate means more of your repayment goes toward the principal rather than interest, which helps you build equity faster and can improve your borrowing capacity if you apply for another loan in the future. It also creates more breathing room in your budget, which is particularly relevant for Truganina buyers managing other costs like childcare or transport.

Some lenders also offer interest rate discounts for borrowers who bundle other products, such as credit cards or transaction accounts. While these can reduce your rate, it is worth considering whether the linked products suit your needs or add unnecessary fees.

Using an Offset Account to Build Equity Faster

An offset account is a transaction account linked to your home loan where the balance offsets the interest charged on your loan amount. If you have a loan of $450,000 and $20,000 sitting in your offset account, you only pay interest on $430,000. This reduces the interest you pay over the life of the loan and helps you build equity more quickly without increasing your repayment.

Offset accounts are typically available on variable rate products and some split loan structures, but not on fixed interest rate home loans. For buyers in Truganina who may have irregular income, such as shift workers or contractors, an offset account provides flexibility. You can park income in the offset without committing it to the loan, and withdraw it if needed without penalty.

As an example, a borrower with a $400,000 loan at a variable interest rate and $15,000 in their offset account could save several thousand dollars in interest over the first few years of the loan. That saving accelerates equity growth and can shorten the loan term without requiring formal extra repayments.

Pre-Approval and Rate Movement Risk

A home loan pre-approval gives you conditional approval for a loan amount before you make an offer on a property. However, pre-approvals are typically valid for three to six months, and if rates rise during that period, your borrowing capacity may be reassessed when you move to formal approval. This can result in a lower approved loan amount than you were originally pre-approved for, even if your financial situation has not changed.

For buyers searching in Truganina, where stock can move quickly and auction competition remains present in certain price brackets, this creates a timing risk. If you are pre-approved near the top of your borrowing capacity and rates increase before settlement, you may need to renegotiate the purchase price, increase your deposit, or withdraw from the sale.

One way to manage this risk is to borrow slightly below your maximum capacity if your budget allows it. This leaves a buffer in case rates move or your circumstances change. It also reduces the chance of financial strain if your income drops or expenses rise after settlement.

Income, Expenses and the Rate Buffer

Lenders assess your borrowing capacity by comparing your net income to your living expenses and financial commitments, then calculating whether you can afford the loan repayment at the assessment rate. Living expenses are calculated using either your actual declared expenses or a benchmark figure based on the Household Expenditure Measure, whichever is higher. This means even if you live frugally, lenders may assume higher expenses than you actually incur.

In practice, reducing your expenses or consolidating debts before applying for a home loan can increase your borrowing capacity more effectively than waiting for rates to fall. Paying off a car loan or credit card can free up several hundred dollars per month in serviceability, which translates to tens of thousands of dollars in additional borrowing power.

For Truganina residents with school-aged children, childcare or education costs are included in living expenses and can significantly reduce borrowing capacity. If one parent plans to return to work after purchasing a property, some lenders will consider future income, provided employment is confirmed and the start date is within a reasonable timeframe.

Call one of our team or book an appointment at a time that works for you. We can review your income, expenses and current rate environment to give you a clear picture of your borrowing capacity and home loan options that suit your situation.

Frequently Asked Questions