Mortgage Repayment Calculator Australia

Enter the amount you plan to borrow in Australian dollars.

Use the advertised or expected annual rate.

Enter the term in years.

Choose how often repayments will be made.

Estimated repayments of the loan amount plus interest

Monthly repayment
$0.00
Total interest payable
$0.00
Total repayment amount
$0.00

Estimate assumes the rate and repayment frequency stay unchanged for the full term.

What is a mortgage repayment calculator?

This mortgage repayment calculator Australia tool estimates regular principal-and-interest repayments on an Australian home loan. Enter the amount borrowed, annual interest rate, loan term and repayment frequency to see the payment for each period, the total interest paid over the loan and the total amount repaid.

It is useful when setting a home-buying budget, comparing loan rates or checking how a shorter term changes the long-run cost. The calculator gives a consistent estimate before lender fees, offset balances, extra repayments and rate changes. It can therefore help narrow down realistic options, but it is not a loan offer or borrowing-power assessment.

How to use the home loan repayment calculator

  1. Enter the loan amount. Use the amount you expect to borrow, not the property purchase price. Subtract your deposit from the purchase price and add any costs that will be financed.
  2. Add the annual interest rate. Enter the comparison rate only if you deliberately want to model it; otherwise use the advertised annual rate for a basic repayment estimate.
  3. Choose the loan term. Australian home loans commonly run for 25 or 30 years, but a shorter term can reduce total interest while increasing each repayment.
  4. Select monthly, fortnightly or weekly. The calculator converts the annual rate into the matching periodic rate and uses the corresponding number of payments.
  5. Review the full result. Compare the repayment with your budget, then look at total interest and total repayments to understand the long-term cost.

Try changing one input at a time. For example, reduce the rate by 0.25 percentage points, shorten the term by five years or compare monthly and fortnightly schedules. A useful home loan repayment calculator is most informative when it is used for side-by-side scenarios rather than a single number.

Mortgage repayment formula explained

The calculator uses the standard amortisation formula for a principal-and-interest loan:

M = P × r(1+r)n ÷ ((1+r)n − 1)

M is the repayment per period, P is the starting loan principal, r is the interest rate for each repayment period, and n is the total number of repayments. For monthly repayments, r is the annual rate divided by 12 and n is the number of years multiplied by 12. Fortnightly uses 26 periods per year and weekly uses 52.

Each repayment contains interest and principal. Early in the loan, more of the payment generally goes toward interest because the outstanding balance is larger. As the principal falls, the interest portion usually declines and more of the same repayment reduces the balance.

Worked example: $500,000 mortgage at 6% for 30 years

For a $500,000 loan with a 6% annual interest rate and monthly repayments over 30 years, the periodic rate is 0.06 ÷ 12, or 0.005. The number of payments is 30 × 12, or 360.

Applying the formula gives an estimated monthly repayment of $2,997.75, usually rounded to about $2,998 per month. If the rate stayed at 6% for all 360 payments, the borrower would repay about $1,079,191 in total, including approximately $579,191 in interest. Real home loans can differ because rates change, interest may be calculated daily, fees may apply, and borrowers may use an offset account or make extra repayments.

Benefits of comparing mortgage repayments

  • Set a more realistic buying budget. A property price becomes easier to assess when it is translated into a regular repayment.
  • Compare interest rates. A small rate difference can materially change total interest across a long loan term.
  • Test the effect of the loan term. A longer term usually lowers each repayment but can increase the total interest paid.
  • Stress-test affordability. Recalculate at a higher rate to see whether the repayment would still fit your budget if variable rates rose.
  • Understand the lifetime cost. The total repayment amount shows why the interest rate and term matter beyond the first monthly payment.

Important: this mortgage calculator Australia estimate is general information only. It assumes a constant interest rate, equal repayments and no fees, offset balance, redraw, extra repayments or interest-only period. Lenders may calculate interest daily and use different rounding. Confirm actual repayments and loan terms with the lender before making a financial decision.

Frequently asked questions

Are fortnightly repayments cheaper than monthly repayments?

Not automatically when both schedules are calculated as exact equivalents from the same annual rate and term. A common saving occurs when a borrower pays half the monthly amount every fortnight: 26 half-payments equal 13 monthly payments each year, so one extra monthly repayment is made. This calculator instead calculates the scheduled payment directly for the selected frequency.

How do extra repayments affect a mortgage?

Extra repayments reduce the principal earlier. That can lower future interest and shorten the loan term, subject to the loan’s rules and any fixed-rate limits or fees. This calculator shows the standard scheduled loan only and does not yet model extra payments.

What does an offset account do?

An eligible offset account reduces the balance used to calculate interest. For example, a $30,000 offset linked to a $500,000 mortgage may cause interest to be calculated on $470,000 while the money remains available in the account. The benefit depends on the loan, offset percentage, fees and balance maintained.

What happens when the interest rate changes?

On a variable-rate loan, a rate rise usually increases the required repayment or extends the time needed to repay the loan if repayments do not adjust. A rate fall can reduce repayments. Re-enter the new annual rate to estimate the payment under the changed scenario.

Does this calculator include lender fees or Lenders Mortgage Insurance?

No. Application, package, valuation, annual and discharge fees are excluded. Lenders Mortgage Insurance is also excluded unless it has already been added to the loan amount you enter.

Is this the same as a borrowing power calculator?

No. A repayment calculator starts with a loan amount and estimates its payment. Borrowing power also considers income, living expenses, other debts, dependants, lender serviceability buffers and credit policy.

Plan the repayment, not just the purchase price

A mortgage can run for decades, so the regular payment and total interest deserve as much attention as the property price. Use this calculator to compare realistic loan amounts, rates, terms and payment frequencies, then stress-test a higher rate before committing. For a complete buying budget, add the relevant stamp duty and other upfront costs, and confirm the final repayment with the lender.