Mortgage Repayment Calculator
Calculate your estimated weekly, fortnightly or monthly mortgage repayments for Australian home loans. See the impact of extra repayments on your loan term and total interest paid.
Loan Details
Formula Used
Principal & Interest:
P = r(1+r)ⁿ / ((1+r)ⁿ − 1) × Loan
Where:
r = Annual rate ÷ periods per year
n = Years × periods per year
52 periods/yr = Weekly
26 periods/yr = Fortnightly
12 periods/yr = Monthly
Enter Your Details
Fill in the loan details on the left and click "Calculate Repayments" to see your results.
About This Mortgage Repayment Calculator
This free Australian mortgage repayment calculator estimates your weekly, fortnightly and monthly home loan repayments using the standard loan amortisation formula. Enter your loan amount, annual interest rate and loan term to see how much each repayment will be under a principal and interest or interest-only structure.
Weekly and fortnightly repayments are calculated using 52 and 26 payment periods per year respectively — not by dividing the monthly figure, which would understate the true repayment. This follows the same method used by most Australian lenders.
You can also enter an optional extra repayment amount to see how much time and interest you could save over the life of your loan. All results are estimates only. Actual repayments will depend on your lender's product, fees and rate. Always confirm with your lender before making a financial decision.
Worked Example
Loan Details
- Loan Amount$500,000
- Interest Rate6.00% p.a.
- Loan Term30 years
- Repayment TypeP&I
Results
- Monthly Repayment$2,997.75
- Fortnightly Repayment$1,384.41
- Weekly Repayment$692.11
- Total Interest$579,190.76
Note: Weekly and fortnightly figures use 52 and 26 payment periods per year respectively, calculated using the standard loan amortisation formula. They are not derived by dividing the monthly figure.
How to Use This Calculator
- 1Enter your Loan Amount — this is the amount you intend to borrow, not the property price. If you are buying a $750,000 property with a $150,000 deposit, your loan amount is $600,000.
- 2Enter the Annual Interest Rate as a percentage (for example, enter 6.25 for 6.25% p.a.). Use your lender's advertised rate, or the comparison rate if you want to include some fees.
- 3Enter the Loan Term in years (commonly 30). Most Australian home loans are written over 25 to 30 years, but shorter terms are available.
- 4Choose a Repayment Frequency — Weekly, Fortnightly or Monthly. The calculator uses 52, 26 and 12 payment periods per year respectively, the same method most Australian lenders use.
- 5Choose a Repayment Type — Principal & Interest (your loan balance reduces over time) or Interest Only (your balance stays the same during the interest-only period).
- 6Optionally add an Extra Repayment per period to see how much time and interest you could save by paying more than the minimum.
- 7Click Calculate Repayments. Use Print Results or Copy Results to keep your estimate.
What the Results Mean
Each figure the calculator returns is an estimate based only on the loan amount, interest rate and term you enter. Here is what each one represents:
- Selected repayment
- The amount you would pay each period (weekly, fortnightly or monthly) under the inputs you entered.
- Repayment summary (all frequencies)
- The equivalent repayment at every frequency for the same loan, so you can compare. Weekly and fortnightly figures use the correct periodic interest rate — they are not the monthly figure divided by 4 or 2.
- Total interest
- An estimate of the total interest you would pay over the full loan term if the rate never changed. It does not include fees.
- Total repaid
- The principal (loan amount) plus total interest — the estimated total amount you would repay over the term.
- Extra repayment savings
- If you added an extra repayment, this shows the shortened loan term, the time saved and the interest saved versus making only the minimum repayment.
Three Realistic Australian Scenarios
Example 1 — A typical $500,000 loan
A borrower takes out a $500,000 principal & interest loan over 30 years at 6.00% p.a.
- Monthly repayment$2,997.75
- Fortnightly repayment$1,382.92
- Weekly repayment$691.32
- Total repaid$1,079,190.95
- Total interest$579,190.95
Over 30 years this borrower repays more than the loan itself in interest — almost $579,000 on a $500,000 loan.
Example 2 — $750,000 at three interest rates
Same $750,000 loan over 30 years, principal & interest, compared at 5.50%, 6.25% and 7.00% p.a.
- Monthly @ 5.50%$4,258.42
- Monthly @ 6.25%$4,617.88
- Monthly @ 7.00%$4,989.77
- Interest @ 5.50%$783,030
- Interest @ 7.00%$1,046,317
A 1.5% rate rise (5.50% to 7.00%) adds about $731 to the monthly repayment and around $263,000 in total interest over the life of the loan.
Example 3 — Monthly vs fortnightly
A $600,000 loan over 30 years at 6.00% p.a. Compare true-equivalent fortnightly repayments with paying half the monthly amount each fortnight.
- Monthly repayment$3,597.30
- True-equivalent fortnightly$1,659.50
- Half-monthly each fortnight$1,798.65
- Extra paid per year$3,597.30
- Loan paid off in~24.5 years
- Interest saved~$148,870
Paying half the monthly amount every fortnight makes 26 payments a year — one extra monthly repayment — shortening the loan by about 5.5 years and saving nearly $149,000 in interest.
Common Mistakes to Avoid
- Using the property price instead of the loan amount. The calculator works on how much you borrow, not the purchase price.
- Dividing the monthly repayment by 4 to get a weekly figure. There are 52 weeks (not 48) in a year, so this understates the true repayment.
- Assuming the interest rate will never change. Most loans are variable; if your rate rises, your repayment and total interest will rise too.
- Forgetting lender fees. Establishment fees, monthly account-keeping fees and Lenders Mortgage Insurance are not included in this estimate.
- Treating the estimate as a quote or offer. Real repayments depend on your lender, product, fees, rate type and assessment — always confirm with your lender.
- Ignoring the effect of compounding. Because interest is charged on the remaining balance, small extra repayments early in the loan save far more than the same amount paid years later.
Frequently Asked Questions
Related PurchaseWise Guides
Estimates only — not advice. All figures from this calculator are estimates based on the inputs you provide and a constant interest rate. They do not include fees, charges or Lenders Mortgage Insurance, and actual repayments will vary. This calculator does not constitute financial, legal, tax or credit advice. Always confirm figures with your lender or a licensed financial adviser before making a decision. See our Financial Disclaimer.
Related Calculator
Property Purchase Calculator
Calculate your deposit, LVR and estimated loan amount.