How repayments are worked out
Repayment = loan × r ÷ (1 − (1 + r)^−number of repayments)
Monthly repayments over 30 years
| Loan | 5.5% | 6.0% | 6.5% |
|---|---|---|---|
| $400,000 | $2,271.16 | $2,398.20 | $2,528.27 |
| $500,000 | $2,838.95 | $2,997.75 | $3,160.34 |
| $600,000 | $3,406.73 | $3,597.30 | $3,792.41 |
| $800,000 | $4,542.31 | $4,796.40 | $5,056.54 |
| $1,000,000 | $5,677.89 | $5,995.51 | $6,320.68 |
Worked example
A $600,000 loan at 6% over 30 years costs $3,597.30 a month, or $1,659.50 a fortnight. Over the full term you pay about $695,029 in interest if the rate never changes.
Paying an extra $200 a month clears it in about 26 years and saves about $106,912 in interest. Paying half the monthly amount every fortnight ($1,798.65) works like one extra monthly repayment a year and clears the loan in about 24.5 years.
Buying soon? Check the stamp duty calculator too.
Frequently asked questions
What are the repayments on a $600,000 mortgage?
At 6% over 30 years, about $3,597 a month or $1,660 a fortnight on principal and interest, or $3,000 a month interest only.
Is it better to pay fortnightly or monthly?
Paying half your monthly repayment every fortnight means 26 half payments, or 13 monthly payments a year, which pays the loan off years sooner.
How much do extra repayments save?
On $600,000 at 6% over 30 years, an extra $200 a month saves about $106,900 in interest and about 4 years.
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Last updated October 2026.