Mortgage Repayment Calculator Australia 2026: Monthly, Extra and Offset

A $600,000 home loan at 6.5% over 30 years costs $3,792 a month in principal and interest, and about $765,000 in interest over the life of the loan. Use the calculator below to work out your own repayment, see what extra repayments or an offset account save, and stress test your loan if rates rise another 3 percentage points. Everything runs in your browser, and nothing is sent anywhere.

Mortgage repayment calculator

Enter your loan details. Leave extra repayments and offset at zero for the basic repayment. The tool works in monthly steps and assumes a constant rate.

How mortgage repayments are calculated

For a principal and interest loan, your repayment is fixed by the loan amount, the interest rate and the term. Each month the lender charges interest on what you still owe, and the rest of your repayment reduces the balance. In the early years most of your repayment is interest, and the principal share grows over time. The standard formula is: repayment = loan x monthly rate / (1 – (1 + monthly rate) to the power of minus the number of months), where the monthly rate is the annual rate divided by 12. On variable loans the lender recalculates your minimum repayment whenever the rate changes, and usually gives you written notice of about 20 days before the new minimum applies (check your loan terms).

Monthly repayments on common loan sizes

These figures are for a 30 year principal and interest loan with a constant rate.

Where interest rates stand

The RBA lifted the cash rate four times in 2026: 0.25 points in February, March, May and September, taking it from 3.60% to 4.60%. Almost every lender has passed on the September rise in full, with most major banks applying it from 9 October 2026. The three big banks other than ANZ were expecting the RBA to hold at its 3 November meeting, while ANZ expected another 0.25 point rise. For context, Finder estimated a rise of about 0.25 points adds roughly $120 a month to the average home loan of about $736,000, and the cash rate was 3.60% before this cycle began. Our interest rate predictions guide looks further ahead.

What extra repayments, offset and fortnightly payments save

Using the example of $600,000 at 6.5% over 30 years, which costs $765,267 in interest with the minimum repayment only:

These results show why paying a little extra early has such a big effect: interest is calculated on the balance, so every dollar you pay off now stops growing for the rest of the loan. An offset account works the same way while keeping the money accessible, but only if you keep the balance in the account. Always confirm with your lender how fortnightly repayments are calculated, because some lenders simply divide the monthly amount by 26 and give no benefit.

Principal and interest or interest only

An interest only loan has lower repayments for a set period, usually up to five years, but you do not reduce the loan. On $600,000 at 6.5%, interest only costs about $3,250 a month compared with $3,792 for principal and interest over 30 years. When the interest only period ends, your repayments rise because the same balance must be paid off over the shorter remaining term. Interest only loans suit some investors, but are usually a poor choice for an owner-occupier.

Does the loan term matter?

A shorter term increases your repayment but cuts the interest. On $600,000 at 6.5%, a 25 year loan costs $4,051 a month and about $615,000 in interest, against $3,792 a month and $765,000 over 30 years. That is a $259 a month increase and a saving of roughly $150,000 in interest. Many borrowers take 30 years and pay it down faster with extra repayments, which keeps the lower minimum in a tight month.

Stress test your repayments

Lenders test whether you could still afford your loan if rates rose. Australian regulators currently require lenders to assess you at a rate 3 percentage points above the loan rate, so a loan at 6.5% is tested at 9.5%. On $600,000 over 30 years that is $5,045 a month. Do your own version of this test, because a repayment you can afford today may be hard to meet if rates rise again. The calculator above shows the repayment at 3 points higher automatically.

Costs beyond your repayments

• Deposit and LMI. If your deposit is under 20% of the price, most lenders charge lenders mortgage insurance, although some government-backed schemes for eligible first home buyers allow a 5% deposit without it. Check Housing Australia for current rules.
• Stamp duty and fees. Use our stamp duty calculator to estimate state government costs, plus legal and application fees.
• Ongoing costs. Council rates, insurance, strata fees and maintenance are separate from your repayments. Our cost of living price guide and salary calculator help you budget.
• Other debts. HECS-HELP, car loans and credit card limits reduce what lenders let you borrow. See our HECS-HELP repayment calculator.

If you are on a temporary visa

Many lenders have extra rules for temporary visa holders, such as larger deposits or limits on income they accept, and policies vary a lot between banks. Foreign persons, which includes most temporary visa holders, also face a ban on buying established dwellings from 1 April 2025 to 31 March 2027, with limited exceptions, and generally need Foreign Investment Review Board approval for other residential purchases. Check the FIRB website and speak to a licensed broker or lawyer before you sign a contract. If you plan to stay long term, see our PR pathways guide.

Ways to lower your repayments

• Ask your lender for a rate cut. Many lenders reduce rates for existing customers who ask or threaten to leave.
• Refinance. Compare rates and fees, and include switching costs. Switching can save thousands, but only if the new rate is lower by enough to cover costs.
• Pay more often. Fortnightly or weekly repayments set at half or a quarter of the monthly amount make an extra monthly payment each year.
• Use an offset account. Keep savings in the offset, and interest is calculated on the balance less the offset.
• Cut other costs. Our money saving tips can free up cash for extra repayments.

Common mistakes

• Using a rate that is out of date, or the advertised rate without checking the comparison rate.
• Borrowing the maximum a lender will give instead of a repayment you can afford if rates rise.
• Not budgeting for the next rate rise, which usually arrives with only a few weeks of notice.
• Treating an offset balance as spending money while counting it as savings.
• Ignoring fees, such as application, valuation, annual package and discharge fees, when comparing loans.

Sources and further reading

• Reserve Bank of Australia, cash rate target (official)
• Finder, RBA cash rate and forecasts
• Finder, lender pass-through of the September 2026 rate rise
• Mozo, 2026 RBA interest rate tracker
• MoneySmart (ASIC), mortgage calculator
• Allens, recent developments in FIRB regulation

Last checked 21 October 2026. Rates, lender policies and regulations change, and the RBA meets again on 3 November 2026, so confirm current figures with your lender. The calculator gives estimates only, uses a constant interest rate, and is not credit or financial advice. Speak to a licensed mortgage broker or your lender before you borrow.

Related guides

More on money and housing: stamp duty calculator, interest rate predictions, salary calculator and novated lease versus buying a car.

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