aus mortgage calculator

Use this AUS mortgage calculator to model your likely repayments before you apply for a home loan. Whether you're buying your first home in Brisbane, upgrading in Melbourne, or investing in Perth, a repayment estimate helps you understand cash flow pressure, total interest, and how long debt could realistically stay with you.

What this AUS mortgage calculator helps you estimate

• Your estimated principal-and-interest repayment per month, fortnight, or week.
• Total interest paid over the life of the loan.
• Total amount repaid including principal and interest.
• How extra repayments can reduce both interest and payoff time.
• How a consistent offset account balance can lower interest charges.
• Loan-to-value ratio (LVR), which lenders use to assess risk.

How mortgage repayments are calculated

1) Work out the loan amount

Your loan amount is usually the property price minus your deposit. For example, an $850,000 property with a $170,000 deposit gives a loan of $680,000.

2) Convert the annual interest rate to a repayment-period rate

If your rate is 6.25% per year and you repay monthly, the periodic rate is 6.25% / 12. If you repay fortnightly, the same annual rate is spread over 26 periods.

3) Apply an amortisation formula

Most Australian owner-occupier loans are amortising loans, meaning each payment includes interest plus principal. Early repayments are interest-heavy; later repayments shift more toward principal.

4) Simulate extras and offset balance

Extra repayments directly reduce principal faster. Offset balances reduce the portion of your loan that accrues interest, often producing substantial savings over decades.

Important Australian mortgage costs people often forget

Repayments are only one part of total home ownership cost. Before signing, budget for:

• Stamp duty: Varies by state/territory and buyer type.
• Lenders Mortgage Insurance (LMI): Common when deposit is below 20%.
• Conveyancing/legal fees: Needed to transfer property title.
• Building and pest inspections: Essential due diligence.
• Loan establishment and valuation fees: Charged by some lenders.
• Moving and setup costs: Utility connections, furniture, and repairs.

That is why this page includes an upfront cost field: it reminds you that borrowing capacity and total cash required are not the same thing.

Fixed, variable, or split: which structure suits you?

Fixed-rate loans

Fixed loans provide repayment certainty for a set period. They are useful when budgeting is tight, but they can include break costs if you refinance or sell early.

Variable-rate loans

Variable rates move with market and lender decisions. You may benefit from lower rates, flexible features, redraw, and full offset accounts, but repayment amounts can rise.

Split loans

A split loan divides the balance between fixed and variable portions. This gives some certainty while preserving flexibility on the variable side.

How to pay off your mortgage sooner in Australia

• Round repayments up (even by $50-$200 each period).
• Direct bonuses, tax refunds, or rent income into extra repayments.
• Keep your salary in an offset account if your lender allows it.
• Review rates regularly and negotiate with your lender.
• Refinance when the overall deal (including fees) is better.
• Avoid extending your term repeatedly when refinancing.

Example scenario

Suppose you borrow $680,000 over 30 years at 6.25%. If you then add even a modest extra repayment every period, the loan can close years earlier and save a significant amount of interest. The calculator above shows this instantly by comparing your base schedule versus your adjusted schedule.

Frequently asked questions

Does repaying fortnightly actually help?

It can, especially if the fortnightly amount results in a higher annual repayment than the monthly equivalent. Even small payment frequency effects plus consistent extra repayments can compound meaningfully.

Is offset better than redraw?

Both can be useful. Offset reduces daily interest calculation, while redraw gives access to extra repayments you've made. The best choice depends on fees, access rules, and your spending discipline.

Can this calculator replace lender assessment?

No. Lenders use serviceability formulas, buffers, living expense models, and policy checks that differ from a simple calculator. Use this as a planning tool, then confirm with a broker or lender.

Final thoughts

A mortgage is usually the largest financial commitment most Australians make. Taking 10 minutes to model scenarios can prevent years of financial stress. Use this calculator to test realistic rates, include true upfront costs, and build a repayment strategy that fits your lifestyle—not just your borrowing limit.