How this mortgage calculator works
Enter a purchase price, deposit, interest rate and term and the calculator returns your repayment for each frequency, the total interest over the life of the loan, and an estimate of Lenders Mortgage Insurance if your deposit is under 20%.
The extra repayment field shows how much interest and time you save by paying above the minimum. The latest RBA cash rate is shown alongside as a reference point for where variable rates are heading.
- Enter the purchase price and your deposit percentage.
- Add the interest rate your lender quoted and the loan term.
- Pick a repayment frequency and try an extra repayment amount.
- Open the amortisation schedule to see principal versus interest by year.
Last reviewed by the myCalculator Editorial Team. General information only, not financial or tax advice.
Frequently asked questions
How are mortgage repayments calculated?
Repayments use the standard amortisation formula M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan amount, r is the interest rate per repayment period and n is the total number of repayments. Most of an early repayment is interest; the principal share grows over time.
How much deposit do I need to avoid Lenders Mortgage Insurance?
Most lenders charge Lenders Mortgage Insurance (LMI) when your deposit is under 20% of the purchase price. The calculator adds an LMI estimate to the loan when your deposit is below 20%. Government schemes such as the Home Guarantee Scheme can waive LMI for eligible buyers.
Does paying fortnightly or weekly save money?
Usually a little. Paying half the monthly amount fortnightly gives 26 half-payments a year, which equals 13 monthly payments instead of 12. The extra payment goes to principal, shortening the loan and cutting total interest. Use the extra repayment field to see the exact saving.
Which interest rate should I enter?
Use the rate quoted by your lender or broker, not the RBA cash rate. The calculator shows the latest RBA cash rate for reference. Variable home loan rates usually sit above the cash rate by a margin that depends on the lender and your loan-to-value ratio.
How accurate is this estimate?
It is a general estimate for planning. Lender fees, offset accounts, rate changes and your credit assessment will change the real figures, so confirm with a licensed broker or your lender before you commit.