How extra repayments save you money

The power of paying more than the minimum

Every dollar you pay above your required repayment goes directly toward reducing your loan principal. Since interest is calculated on the outstanding balance, a lower principal means less interest accrues in the next period. This creates a compounding effect — each extra payment reduces the base that future interest is calculated on.

A practical example

Consider a $500,000 loan at 6.0% over 30 years. The minimum monthly repayment is approximately $3,000. If you add just $200 per month in extra repayments:

You save approximately $97,000 in total interest and pay off the loan 5 years and 3 months early. That $200 per month — roughly $46 per week — translates to nearly six figures in savings over the life of the loan.

Strategies for making extra repayments

Round up your repayments — if your minimum is $2,870, pay $3,000. The difference barely affects your weekly budget but compounds significantly over decades.

Direct windfalls to your mortgage — tax refunds, bonuses, or gifts can make a meaningful dent when applied as lump sum payments.

Switch to fortnightly — paying half your monthly amount every two weeks results in one extra full payment per year without changing your fortnightly budget.

Use an offset account — if your lender offers one, keeping your savings in an offset account reduces the balance that interest is calculated on, achieving the same effect as extra repayments while keeping funds accessible.

Watch for redraw restrictions

Before committing to extra repayments, check your loan’s redraw terms. Some lenders restrict access to extra funds or charge fees to redraw. An offset account avoids this issue entirely since the funds remain in a separate accessible account.

Why the early years matter most

The arithmetic of amortisation rewards extra repayments made early in the loan more than late ones. The mechanic is simple: interest in any given period is calculated on the outstanding balance at the start of that period. Extra repayments made in year one reduce the balance against which interest accrues for the entire remaining loan term — twenty-nine years of compounding savings on the principal you removed early.

A $5,000 lump sum applied in month one of a 30-year loan at 6% saves roughly $25,000 in total interest across the loan life. The same $5,000 lump sum applied in year fifteen saves only about $5,500 in total interest — because there are fewer years left for the interest saving to compound.

This is not an argument against making extra payments later in the loan. Late extra payments still save money. It is an argument that the same dollars are roughly five times more powerful in the first few years than in the final few years. Households with surplus capital in early-loan years should prioritise applying it to the mortgage over almost any other use, because the long-run interest avoidance is dramatic.

A worked example showing the compounding

Take a $500,000 mortgage at 6% over 30 years with a base monthly repayment of approximately $3,000. Three scenarios:

No extra repayments. Loan paid off in 360 months. Total interest paid: roughly $580,000. Total cost: roughly $1,080,000.

$200/month extra from year one. Loan paid off in approximately 295 months — almost 5.5 years early. Total interest paid: roughly $483,000. Saving: approximately $97,000 in interest.

$200/month extra starting only in year ten. Loan paid off in approximately 320 months — roughly 3.5 years early. Total interest paid: roughly $530,000. Saving: approximately $50,000 in interest.

Same extra repayment of $200/month in both cases. The first scenario saves nearly twice as much because the extra payments work against the highest-balance early years. The lesson is to start extra payments as soon as the household budget can sustain them, and to commit to maintaining them rather than treating them as a discretionary year-by-year decision.

Common mistakes to avoid

Several patterns recur where extra repayments fail to deliver the expected savings.

Reducing savings too aggressively to fund extra repayments. A household that runs down its emergency fund to make extra mortgage payments creates a fragility risk. If a job loss or major repair arrives, the household may be forced to take expensive consumer debt despite the extra mortgage payments. The discipline is to build the emergency fund first, then redirect surplus to extra repayments — not the other way around.

Forgetting redraw and offset alternatives. For loans with offset accounts, parking surplus cash in offset produces the same interest saving as extra repayment, while keeping the funds accessible. For loans with free redraw, extra repayments retain partial accessibility. Investors with investment-property mortgages should be especially careful — direct extra repayments to a deductible loan can complicate tax treatment in ways that an offset account avoids.

Not checking redraw fees before relying on access. Some lenders charge per redraw or restrict the number of redraws per year. A borrower who assumes they can pull funds back any time may find restrictions when they actually need to.

Stopping extra repayments after the first rate cut. When rates fall, the minimum repayment falls — which feels like a windfall. The strongest move is to keep paying the previous repayment amount. Every dollar above the new minimum goes directly to principal.

Lump sum timing. Some lenders apply lump sum payments only on a monthly cycle. A lump sum paid the day after a billing cycle may not reduce the interest charge for the current period. Confirm timing with the lender for large extra payments.

Model your savings

Use our extra repayment calculator to see exactly how much interest you save and how many years you cut from your loan with different extra payment amounts.

This guide is general information only and does not constitute financial advice. Loan products, redraw terms, and tax treatments vary by lender and jurisdiction. Confirm specific product terms with your lender before relying on any modelled saving.