To calculate mortgage repayments in Australia, you will need to know the following information:

- The amount of the loan: This is the total amount you are borrowing from the lender.
- The interest rate: This is the percentage of the loan amount that you will have to pay in addition to the principal amount.
- The loan term: This is the length of time over which you will be paying back the loan, usually expressed in years.
- The frequency of payments: This is how often you will be making payments towards the loan, usually monthly or fortnightly.

Once you have this information, you can use the following formula to calculate your mortgage repayments:

Monthly repayment = (Loan amount x Interest rate) / (1 – (1 + Interest rate)^(-Loan term x 12))

Where:

- Loan amount is the total amount you are borrowing
- Interest rate is the annual interest rate on the loan, expressed as a decimal
- Loan term is the length of the loan in years
- 12 is the number of months in a year

For example, if you were borrowing $300,000 at a 4.5% interest rate over a 30-year loan term and making monthly payments, your monthly repayment would be:

Monthly repayment = (300,000 x 0.045) / (1 – (1 + 0.045)^(-30 x 12)) = $1,480.06

Note that this is just an estimate and does not include any additional fees or charges that may be applicable. It’s always a good idea to discuss your mortgage options and get a detailed loan quote from a lender before making any decisions.