Mortgage Repayment Calculator
Calculate your Australian home loan repayments. Compare principal & interest vs interest-only payments.
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How Mortgage Repayments Work in Australia
Australian home loans are typically repaid over 25–30 years. Your repayment amount depends on three factors: the loan amount, the interest rate, and the loan term. Most borrowers choose principal and interest (P&I) repayments, where each payment covers both the interest owing and reduces the loan balance.
Principal & Interest vs Interest Only
Principal & Interest (P&I): Each repayment covers the interest charged that period plus a portion of the original loan amount. Early in the loan, most of your repayment goes to interest. Over time, a larger proportion goes to reducing the principal. This is the standard and most cost-effective repayment method.
Interest Only (IO): You only pay the interest charged — the loan balance doesn't reduce. This results in lower repayments short-term but costs significantly more over the life of the loan. Interest-only periods are typically limited to 5 years for owner-occupiers and 10 years for investors. When an interest-only period ends, the interest-only vs principal and interest calculator shows how much your repayments rise once you start paying off the balance.
A worked example
$700,000 over 30 years at 6.5%, principal and interest, is $4,424 a month. Total interest over the full term is $892,811 — 128% on top of what was borrowed, which is the number most repayment tables leave out.
Already have a loan? See whether a lower rate pays for the switch with the refinancing calculator, and if you're on a fixed rate, check the break cost calculator before you move.
Fortnightly vs Monthly Repayments
Switching from monthly to fortnightly repayments (paying half the monthly amount every two weeks) is one of the simplest ways to save on your mortgage. Because there are 26 fortnights in a year, you effectively make 13 monthly payments instead of 12 — paying off your loan years earlier and saving thousands in interest. If you've got a lump sum rather than spare cash each month, compare the two with the lump sum vs extra repayments calculator.
Current Interest Rates
As of August 2026, the average rate on new owner-occupier principal-and-interest loans was 6.15% a year, on a Reserve Bank series that mixes variable and fixed loans. The cash rate target is 4.60%, effective 30 September 2026. A 0.25 percentage point move in a loan rate — the size of a standard cash-rate step — is priced on three loan sizes in the 3 November guide. The decision is announced at 2.30pm Sydney time that day. The guide does not guess it. Sources: RBA lenders' interest rates, August 2026 and RBA cash rate target.