Mortgage Repayment Calculator | Free Tool

Loan details

Loan amount

Interest rate6.2%

Loan term30 years

Repayment type

Extra monthly repayment

Monthly repayment

Principal & interest

Monthly

Fortnightly

Weekly

Loan summary

Total repaid over term$0

Total interest paid$0

Interest as % of loan0%

Principal

Interest

Year-by-year breakdown

Year	Balance	Principal paid	Interest paid

Want a better rate?

We compare 50+ lenders to find the lowest rate for your situation. For example, refinancing a $700,000 loan from 6.5% to 5.9% saves around $270 per month, roughly $3,270 a year in repayments.

How this calculator works

This calculator uses the standard amortisation (annuity) formula that Australian lenders use for principal and interest loans. Your annual interest rate is divided by 12 to get a monthly rate, and the repayment is the fixed monthly amount that fully repays the loan over the selected term. For interest-only repayments, the calculator multiplies the loan balance by the monthly rate, since no principal is repaid during an interest-only period.

Total interest is the difference between all repayments over the term and the original loan amount. The year-by-year table simulates each month of the loan, splitting every repayment into its principal and interest components as the balance falls. When you enter an extra monthly repayment, the calculator re-runs this month-by-month simulation to show how many years earlier the loan finishes and how much interest is saved.

Key assumptions used by the calculator:

Principal and interest repayments use the standard amortisation formula with monthly compounding.
Interest-only repayments equal the loan balance multiplied by the monthly interest rate.
Fortnightly figures are the monthly repayment divided by 2, and weekly figures are the monthly repayment multiplied by 12 and divided by 52. These show the same annual total, not an accelerated repayment strategy.
The interest rate is assumed to stay constant for the whole term.
Fees, offset account balances, redraw, and rate changes are not included.

This is a general estimate only, not credit advice or a loan offer. Actual repayments depend on your lender's rate, fees, and loan structure.

Repayment FAQ

How are mortgage repayments calculated?

Lenders use an amortisation formula: the annual rate is divided by 12, and the repayment is set so the loan is fully repaid over the term. Early repayments are mostly interest; later repayments are mostly principal. On a $750,000 loan at 6.2% over 30 years, the monthly repayment is roughly $4,594, and total interest over the term can approach the original loan amount.

Do fortnightly repayments pay off my loan faster?

Only if you pay half the monthly amount every fortnight. Because there are 26 fortnights in a year, that approach makes the equivalent of 13 monthly repayments instead of 12, which can cut years off a 30-year loan. If your lender simply splits the monthly amount into true fortnightly instalments, the annual total is the same and there is no shortcut.

How much can extra repayments save?

Even modest extra repayments can save a large amount of interest because they reduce the balance that interest is charged on every month. As a guide, an extra $500 per month on a $750,000 loan at 6.2% over 30 years can save well over $100,000 in interest and shorten the loan by several years. Check whether your loan allows unlimited extra repayments; some fixed loans cap them.