Home Loan Repayment Calculator — Australia
Australian home loan repayments monthly, fortnightly or weekly, interest-only periods, offset and extra-repayment savings, total interest, payoff date and the repayment at the APRA 3% assessment buffer.
| Monthly equivalent | — |
|---|---|
| Interest-only period | — |
| Total interest over the loan | — |
| Total repaid | — |
| Effect of offset & extra repayments | — |
| Loan paid off | — |
| If rates rise 1% / 2% | — |
| Fortnightly vs monthly | — |
In short
A $650,000 Australian home loan at 5.89% over 30 years costs $3,851 a month and $736,442 of interest; paying half that amount fortnightly (26 payments a year) clears it about 5 years 5 months earlier and saves roughly $155,000, a $50,000 offset balance saves about $198,000, and lenders assess affordability at the rate plus a 3-percentage-point buffer — $5,179 a month at 8.89%.
Who this is for: Australian borrowers comparing monthly and fortnightly repayments, interest-only investors, and owners weighing an offset account or extra repayments.
How Australian home-loan repayments work
Australian lenders calculate interest daily on the outstanding balance and charge it monthly, so the principal-and-interest repayment is the standard amortised instalment over the term — 30 years on most loans. Paying fortnightly as half the monthly amount makes 26 half-payments, the equivalent of 13 monthly payments a year, which is why it clears the loan years earlier. An offset account reduces the balance on which interest is calculated every day, and extra repayments go straight to principal; the calculator shows the interest and time both save.
Interest-only periods (common for investors, usually 5 years) keep the payment low but leave the balance untouched, so the later P&I payment is higher because it amortises over fewer years. The stress row shows the payment at +1% and +2% and at the 3-percentage-point APRA buffer lenders must use to assess whether you can afford the loan.
See also: Rent vs Buy Calculator — Australia, LMI Calculator — Lenders Mortgage Insurance Australia, Stamp Duty Calculator — NSW, VIC & QLD 2026–27.
Assumptions
- Principal-and-interest repayment amortised over the term; fortnightly = half the monthly amount 26 times a year, weekly = a quarter 52 times.
- Interest accrued per period at the annual rate divided by the number of periods; offset balance deducted before interest.
- Interest-only period charges interest on the full balance, then P&I over the remaining term.
- Fees, LMI, rate changes and lender rounding excluded.
Worked example
Repayment $3,851 a month ($46,212 a year); total interest $736,442 over 30 years. Fortnightly at $1,926 clears the loan about 5 years 5 months earlier and saves roughly $155,000. A $50,000 offset balance held throughout saves about $198,000 and 4 years 3 months. At +2% the repayment would be $5,179; at +1% $4,720; the lender assesses you at 8.89% — $5,179 a month.
Frequently asked questions
How is interest calculated on an Australian mortgage?
Daily on the balance owing (balance × rate ÷ 365), added to the loan monthly — which is why offset balances and early extra payments save so much.
Is fortnightly really cheaper?
Only if you pay half the monthly amount every fortnight (26 payments = 13 months of repayments a year). A true fortnightly amount recalculated over the term saves nothing.
What is the comparison rate?
A rate that folds the lender's upfront and ongoing fees into the interest rate on a $150,000 25-year loan for comparison; on larger loans the fee effect is smaller than it suggests.
Offset or redraw?
Offset keeps the money in your account and saves interest daily; redraw puts extra repayments in the loan and lets you take them back, usually with limits. Offset is more flexible, redraw often cheaper.
Can I make extra repayments on a fixed loan?
Usually capped (e.g. $10,000–$30,000 a year) with break costs beyond that; variable loans allow unlimited extras.
What rate will the bank assess me at?
Your rate plus a 3 percentage point buffer (APRA), or the lender's floor rate if higher — see the borrowing power calculator.
What is the difference between a redraw and an offset?
Redraw holds extra repayments inside the loan; offset holds them in a linked account. Both cut interest daily; offset keeps the cash accessible without lender limits.
Why does my bank’s repayment differ by a few dollars?
Lenders accrue interest daily on actual calendar days and round repayments up; this calculator uses equal monthly periods.
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