Your loan. Your numbers.Loan Repayment Calculator

What does this calculator do?

Estimate your home loan repayments and compare two scenarios side by side. See how the loan amount, interest rate, term, repayment frequency and extra payments affect your estimated costs and payoff date.

You can use it for a proposed loan or an existing mortgage. For an existing loan, enter the outstanding balance and remaining term. It estimates repayments; it does not assess borrowing capacity or confirm loan approval.

How to use the calculator

1. Set up Scenario A. Enter your loan amount, annual interest rate, term and start date. The starting figures are $750,000, 5.95% and 30 years; these are editable assumptions, not a loan offer.
2. Choose your repayment settings. Select principal and interest or an interest-only period of one to five years. Choose the repayment frequency available for that type.
3. Add fees and extra repayments. Enter a fee and its timing, then any extra amount you plan to pay each selected period.
4. Set up Scenario B. Select the Scenario B tab and change the details you want to compare. Valid changes update the results automatically.
5. Compare the results. Review both the regular payment and total costs. Check the estimated payoff dates and savings before deciding what to discuss with your broker.

Comparing Scenario A and Scenario B

For a clear comparison, start with the same amount, term and start date in both scenarios. Then change one setting in Scenario B—for example, the interest rate, repayment frequency or extra payment.

If you change the loan amount or term as well, the total-payment difference reflects those changes too. It should not be read as a saving caused solely by a lower rate.

Understanding your results

Monthly, fortnightly and weekly repayments

With Our Strategy principal-and-interest loans, this calculator first works out the monthly repayment. It divides that amount by two for fortnightly repayments or four for weekly repayments, then rounds the result up to the next whole dollar. Monthly repayments are also rounded up.

With 26 fortnightly or 52 weekly payments each modelled year, this approach pays approximately 13 monthly amounts annually, before extras. That is why changing frequency can reduce the estimated loan term and interest.

Standard Repayment: the monthly repayment is multiplied by 12 and divided by 26 for fortnightly or 52 for weekly. This spreads the annual repayment amount across the selected frequency rather than paying approximately 13 monthly amounts each year. Interest is calculated per payment period using the unrounded repayment.

Principal and interest or interest only

Principal-and-interest repayments cover interest and reduce the loan balance. An interest-only period initially covers interest without scheduled principal reduction. When that period ends, the remaining balance must be repaid over the remaining loan term, which can increase repayments. Read Moneysmart’s interest-only guide.

This calculator offers interest-only periods of one to five years, shorter than the total loan term. Interest-only scenarios use monthly repayments and then switch to principal and interest. The result shows the subsequent payment separately. Any extra repayments entered are applied to reduce the balance in this model.

Extra repayments and loan fees

The extra amount applies each selected payment period: an extra $100 monthly is different from an extra $100 weekly. It is added to the scheduled repayment until the balance is cleared, with the final payment reduced where needed.

Fees are paid separately rather than added to the loan balance. A one-off fee is included at the start; annual fees are included at the end of each completed modelled loan year; per-repayment fees apply to each payment. Only the fees you enter are included.

Check your loan’s conditions before making extra payments, including any limits or charges. This calculator does not model break costs, offset accounts, redraw withdrawals or changing interest rates.

Payoff dates and calculation assumptions

The rate stays constant throughout the projection. For Our Strategy principal-and-interest loans, interest accrues daily using the annual rate divided by 365, and is rounded to cents when posted at month end. Scheduled payments are rounded up to whole dollars; total interest is rounded up to whole dollars. The Our Strategy reference model excludes unposted interest in a final partial month. Standard Repayment estimates instead use equal payment periods, retain unrounded repayment amounts internally, and round displayed payments and interest totals up to whole dollars. Both approaches use a separate periodic estimate for interest-only scenarios.

The Our Strategy principal-and-interest model uses a reference calendar starting on 1 January of the entered start year, including leap years. Monthly payments fall at month end; weekly and fortnightly payments occur every seven or 14 days. Standard Repayment estimates round the repayment duration up to a whole month. The displayed payoff date in either approach adds the estimated whole-month duration to your entered start date. It is an indicative date, not a daily settlement quote.

Totals represent principal plus modelled interest and entered fees; they are not simply the displayed regular payment multiplied by the payment count. Actual lender figures can differ because of daily interest, rounding, payment dates, fees and product terms. See Moneysmart’s mortgage calculator for further general information.

Frequently asked questions