Mortgage repayment calculator
Work out your weekly, fortnightly or monthly home loan repayments, the total interest you will pay, and how your balance falls over time.
Rates last checked . See how we calculate.
Your repayment
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Then once the interest-only period ends.
- Total interest
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- Total repaid
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Show yearly repayment schedule
| Year | Principal paid | Interest paid | Balance |
|---|
Quick answer: a $600,000 home loan at 6.50% p.a. over 30 years costs about $3,792 a month, $1,750 a fortnight or $875 a week on principal and interest. Over the full term you would pay around $765,300 in interest, so the total repaid is about $1.37 million.
How mortgage repayments are calculated
Australian lenders use the standard amortisation formula. Each repayment is the same amount, but the split changes over time: early repayments are mostly interest, later ones are mostly principal.
The formula is M = P × r ÷ (1 − (1 + r)−n), where:
- M is the repayment each period
- P is the amount you borrow
- r is the interest rate per period (the annual rate divided by 12, 26 or 52)
- n is the total number of repayments (years × 12, 26 or 52)
Interest is charged on the balance you owe, so as the balance falls, more of each repayment goes to principal. On a $600,000 loan at 6.50%, about $38,800 of the first year's $45,500 in repayments is interest. By year 10, interest has dropped to about $33,500 a year.
Not sure how much to enter? Start with the borrowing power calculator, then add stamp duty to see the full cost of buying.
Repayments on common loan amounts
| Loan amount | Monthly | Fortnightly | Weekly | Total interest |
|---|---|---|---|---|
| $400,000 | $2,528 | $1,166 | $583 | $510,178 |
| $500,000 | $3,160 | $1,458 | $729 | $637,722 |
| $600,000 | $3,792 | $1,750 | $875 | $765,267 |
| $700,000 | $4,424 | $2,041 | $1,020 | $892,811 |
| $800,000 | $5,057 | $2,333 | $1,166 | $1,020,356 |
| $1,000,000 | $6,321 | $2,916 | $1,458 | $1,275,445 |
Weekly, fortnightly or monthly: does it matter?
If your lender calculates a true fortnightly repayment (the formula above with 26 periods), the saving is small. On $600,000 at 6.50% it is less than $1,000 over 30 years.
The real saving comes from paying half your monthly repayment every fortnight. Because there are 26 fortnights in a year, you end up making the equivalent of 13 monthly repayments instead of 12. On the same $600,000 loan, paying $1,896 a fortnight instead of $1,750 clears the loan in about 24 years and saves around $176,000 in interest. Check how your lender sets fortnightly repayments before you switch.
Principal and interest vs interest-only
With an interest-only loan you pay just the interest for a set period, usually 1 to 5 years, so the balance does not fall. On $600,000 at 6.50%, interest-only repayments are $3,250 a month.
The catch comes when the interest-only period ends. You then have to repay the full $600,000 over the remaining 25 years, so repayments jump to about $4,051 a month. Across the whole loan you pay around $810,400 in interest, about $45,100 more than principal and interest from day one. Interest-only rates are also usually higher.
What the rate rise means for repayments
The RBA lifted the cash rate to 4.60% on 29 September 2026. A 0.25 percentage point rise adds about $100 a month to the repayment on a $600,000, 30-year loan (from $3,792 at 6.50% to $3,892 at 6.75%). Use the calculator to test your budget at a rate 1 to 2 points above your current rate. Already have a loan? See whether a lower rate is worth chasing with the refinance calculator.
What this calculator does not include
- Fees such as application, settlement, annual package or monthly account fees
- Rate changes over the life of the loan. It assumes your rate stays the same.
- Lenders mortgage insurance (LMI) added to the loan. Use the LMI calculator for that.
- Offset or redraw balances. Use the extra repayment and offset calculator.
Want to compare actual lender rates? See today's rates on homeloaninterestrates.au.
Frequently asked questions
How much is the monthly repayment on a $500,000 mortgage?
At 6.50% p.a. over 30 years, about $3,160 a month on principal and interest. Over 25 years it rises to about $3,376 a month, but you save over $120,000 in interest.
How much interest will I pay over the life of my loan?
It depends on the rate, term and loan size. At 6.50% over 30 years, total interest is roughly 1.28 times the amount borrowed. A $600,000 loan costs about $765,300 in interest if the rate never changes and you only make minimum repayments.
Is it better to pay my mortgage fortnightly?
Paying half your monthly repayment every fortnight is the version that saves money, because it adds up to one extra monthly repayment each year. On a $600,000 loan at 6.50% that saves around $176,000 and about 6 years.
Does a shorter loan term save money?
Yes. Repayments are higher but you pay interest for fewer years. A $600,000 loan at 6.50% costs $4,051 a month over 25 years compared with $3,792 over 30 years, and saves about $149,900 in interest.
How accurate is this mortgage calculator?
It uses the same amortisation formula lenders use, so the repayment for a given rate and term should match within a few dollars. Real repayments can differ because of fees, rate changes and how your lender rounds or schedules payments.
Sources
- Reserve Bank of Australia, cash rate target and monetary policy decisions
- ASIC Moneysmart, mortgage calculator methodology and interest-only loan guidance
- Our calculation methods