When to Lock In Your Rate or Wait

A shift in interest rates changes your borrowing capacity before it changes anything else.

When lenders assess your application, they use a higher rate than what you'll actually pay. That assessment rate determines the maximum loan amount you can service. When actual rates rise, that assessment rate climbs too, and your borrowing power contracts. For buyers in Charlestown where the median continues to move, that contraction can put properties that were within reach last month out of range today.

How Assessment Rates Shrink Your Loan Amount

Lenders don't assess your application using the rate advertised on their website. They add a buffer, typically between 2.5% and 3%, to account for future rate rises. This assessment rate is the figure that dictates whether you can service the loan. When the actual variable rate increases, the buffer moves with it, and the lender calculates your maximum borrowing capacity at a higher cost.

Consider a buyer earning $90,000 per year with minimal debts. At an assessment rate of 6.5%, they might qualify for a loan of around $530,000. If rates rise and the assessment rate moves to 7%, that same buyer now qualifies for closer to $500,000. The income hasn't changed. The debts haven't changed. But the borrowing capacity has dropped by $30,000 because the lender assumes a higher repayment cost.

That reduction matters in Charlestown, where buyers are competing for family homes near Charlestown Square and established properties along Ridley Street. A $30,000 drop in borrowing power can be the difference between making an offer and missing out.

Variable Rates Give You Flexibility Until They Don't

A variable rate loan adjusts with the market, which means your repayments can fall when rates drop. It also means your repayments can climb when rates rise. That flexibility is valuable when you expect rates to stabilise or decline, but it becomes a risk when rates move against you after settlement.

The risk isn't just financial. If you borrow at your maximum capacity on a variable rate and rates rise six months later, your repayments increase. You're still obligated to meet those repayments, but your household budget tightens. If you need to refinance or apply for additional credit, lenders will reassess your capacity at the new, higher rate. That reassessment can limit your options even if you've been meeting every repayment on time.

In our experience, buyers who stretch their borrowing capacity on a variable rate often find themselves locked into that loan longer than they planned. The flexibility they valued becomes irrelevant once they can't afford to move.

Fixed Rates Lock In Certainty but Limit Adjustment

A fixed rate secures your repayment amount for a set term, usually between one and five years. During that period, your repayments don't change regardless of what happens to the variable market. That certainty makes budgeting straightforward and protects you from rate rises that would otherwise reduce your serviceability.

The limitation is that you're committed. If rates fall during your fixed term, your repayments stay where they are. If you want to refinance or pay down the loan faster, you'll likely face break costs. Those costs are calculated based on the difference between your fixed rate and the lender's current wholesale funding cost. When rates have fallen, break costs can run into the thousands.

For buyers in Charlestown purchasing near the median, a fixed rate makes sense when you value certainty over flexibility. If your income is stable and you don't plan to sell or refinance within the fixed term, locking in your rate removes one variable from your financial planning.

Split Loans Balance Risk Without Overcomplicating

A split loan divides your borrowing between a fixed portion and a variable portion. You might fix 60% of the loan and leave 40% variable, or split it 50/50. The fixed portion protects you from rate rises. The variable portion gives you flexibility to make extra repayments or refinance without paying break costs on the entire balance.

This structure works when you're not certain which direction rates will move but you want some protection either way. The fixed portion caps your exposure to rate rises. The variable portion allows you to take advantage of rate falls or adjust your repayments as your income changes.

In a scenario like this: a buyer borrows $550,000 to purchase in Charlestown. They fix $330,000 at 5.8% for three years and leave $220,000 variable at 6.2%. Rates rise to 6.7% within 12 months. The fixed portion is unaffected. The variable portion increases, but the impact is limited to 40% of the loan. The buyer's overall repayment rises, but not as sharply as it would have on a fully variable loan. When rates stabilise two years later, they can start making extra repayments on the variable portion without penalty.

The outcome is manageable. The buyer avoided the full impact of the rate rise without locking in the entire loan at a rate that might look high if the market shifts again.

Offset Accounts Reduce Interest Without Changing Your Rate

An offset account is a transaction account linked to your home loan. The balance in the offset reduces the loan balance on which interest is calculated. If you have a $500,000 loan and $20,000 in your offset, you only pay interest on $480,000. Your repayments stay the same, but more of each repayment goes toward reducing the principal.

This feature is standard on most variable rate loans and some split loan structures. It's rarely available on fully fixed loans. For buyers with irregular income or those building a deposit for an investment property, an offset account provides a way to reduce interest without committing those funds to the loan permanently.

We regularly see buyers underestimate the value of an offset because it doesn't feel as immediate as a rate discount. Over time, though, maintaining $15,000 to $25,000 in an offset can reduce your interest cost by thousands and shorten your loan term without changing your repayment schedule.

Rate Discounts Are Negotiable but Not Automatic

Most lenders advertise a standard variable rate and then apply discounts based on your loan size, deposit, and overall financial position. A buyer with a 20% deposit and strong serviceability might receive a discount of 0.6% to 0.9% off the standard rate. A buyer with a 10% deposit and limited savings might receive 0.3% or no discount at all.

Those discounts are negotiable, but not every broker or buyer knows how to position the application to secure them. Lenders assess discount eligibility based on loan-to-value ratio, employment type, and whether you're consolidating other products like insurance or credit cards. If you're applying through a broker, the broker's relationship with the lender can also influence the discount offered.

The difference between a 0.3% discount and a 0.8% discount on a $500,000 loan is around $2,500 per year in interest. That's not a rounding error. It's a material impact on your cost of borrowing and your ability to build equity faster.

When to Lock In and When to Wait

If rates are rising and you're close to your maximum borrowing capacity, lock in at least part of your loan. The cost of waiting is that your serviceability deteriorates further and the property you're targeting moves out of range. A fixed rate or split structure protects your borrowing capacity and gives you certainty over your repayments during the initial years of the loan.

If rates are stable or falling and you're borrowing well within your capacity, a variable rate gives you more flexibility. You can make extra repayments, use an offset account, and refinance without penalty if a lower rate becomes available. Your borrowing capacity isn't under immediate pressure, so you're not forced to lock in a rate that might look high in six months.

The decision comes down to your income stability, your deposit size, and how much borrowing capacity you're using. If you're stretching to secure the property, protection matters more than flexibility. If you're comfortable with your serviceability buffer, flexibility matters more than protection.

Call one of our team or book an appointment at a time that works for you. We'll assess your borrowing capacity at current rates, compare your home loan options across lenders, and structure a loan that keeps your property goal within reach.

Frequently Asked Questions