About the Australia Home Loan Calculator
This Australian home loan calculator works out your principal-and-interest repayments on a variable or fixed-rate mortgage in Australian dollars. Choose monthly, fortnightly or weekly repayments to match your pay cycle, and see the total interest over the life of the loan and how long it will take to pay off.
Australian borrowers can often cut years off their loan with extra repayments or an offset account — a transaction account linked to the loan whose balance is subtracted before interest is charged. Enter an extra amount per repayment and your average offset balance to see the time and interest you would save. It suits first home buyers, refinancers and investors comparing lenders.
Repayments here are true weekly or fortnightly amounts calculated for that frequency. Some lenders instead set fortnightly repayments at half the monthly amount, which pays the loan off faster — you can model that by adding the difference as an extra repayment. The rate is assumed constant; variable rates will change over time.
With the default inputs, the required repayment is A$3,674.81. Change any value above to recalculate instantly.
How to use the australia home loan calculator
- 1Enter the amount you plan to borrow and the interest rate from your lender.
- 2Set the loan term — 30 years is standard in Australia.
- 3Choose monthly, fortnightly or weekly repayments to match your pay.
- 4Optionally add an extra amount per repayment and an offset account balance.
- 5Compare total interest and payoff time with and without the extras.
Formula and method
The repayment R uses the standard amortisation formula with a periodic rate i (annual rate divided by 12, 26 or 52) and N repayments in total. Interest is charged each period on the outstanding balance, and the rest of the repayment reduces the principal.
With an offset account, interest is charged only on the balance minus the offset amount, while the repayment stays the same — so more of each repayment goes to principal. Extra repayments are added to every scheduled repayment. The calculator simulates the loan period by period to find the new payoff time and the interest saved compared with standard repayments.
- R
- Repayment per period
- P
- Loan amount
- i
- Interest rate per repayment period
- N
- Total number of repayments
Worked examples
A$600,000 at 6.2% over 30 years, monthly
Borrowing A$600,000 at 6.2% p.a. over 30 years costs A$3,674.81 a month. Over the full term you would pay about A$722,933 in interest — more than the original loan.
Same loan with fortnightly repayments
True fortnightly repayments are A$1,695.26. Because interest is calculated slightly more often on a falling balance, total interest is about A$722,303 — only marginally less than monthly.
A$500 extra per month plus a A$50,000 offset
Keeping A$50,000 in an offset account and paying A$500 extra each month clears the loan in 19 years 6 months instead of 30. Total interest falls to about A$374,770, saving roughly A$348,163.
Frequently asked questions
Are fortnightly repayments better than monthly?+
If your lender sets fortnightly repayments at half the monthly amount, you make the equivalent of 13 monthly repayments a year and pay the loan off years sooner. True fortnightly repayments calculated for 26 periods save only a little interest.
How does an offset account work?+
An offset account is a transaction account linked to your home loan. Its balance is subtracted from the loan balance before interest is calculated, so A$20,000 in offset on a A$500,000 loan means you pay interest on A$480,000, while your money stays accessible.
Is an offset account better than extra repayments?+
Both reduce interest by the same amount per dollar. Offset keeps the money easily accessible and, on investment loans, can preserve tax deductibility. Extra repayments may go into a redraw facility, which lenders can restrict.
How much can I borrow for a home loan in Australia?+
Lenders assess your income, expenses and debts and must test whether you could still repay if rates rose — APRA expects a serviceability buffer of at least 3 percentage points above the loan rate.
What is the difference between principal and interest and interest-only?+
Principal-and-interest repayments pay down the loan every period. Interest-only repayments cover just the interest for a set period (often 1–5 years), so the balance does not fall and repayments jump when the period ends.
Should I choose a fixed or variable rate?+
Fixed rates give certainty for 1–5 years but often limit extra repayments and offset. Variable rates can rise or fall but usually allow unlimited extras and a full offset. Many borrowers split the loan between both.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.
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