Calculate Your Repayments
Estimate your regular home loan repayment, total interest, and potential savings from extra repayments.
What this home loan repayment calculator does
This calculator helps you estimate how much your home loan repayments may be and how much interest you are likely to pay over the life of the loan. It also shows what happens if you add extra repayments each period, which can reduce both your payoff time and total interest cost.
It is designed for quick planning. You can test different loan amounts, rates, terms, and repayment frequencies to see how sensitive your mortgage is to small changes.
How repayment calculations work
Core inputs
- Loan amount: The total principal borrowed.
- Interest rate: Annual percentage rate used for the estimate.
- Loan term: Number of years over which the loan is scheduled.
- Repayment frequency: Monthly, fortnightly, or weekly repayments.
The repayment formula
Standard home loan calculations use an amortization formula. Each repayment includes:
- An interest portion (cost of borrowing), and
- A principal portion (reducing what you owe).
Early in the loan, more of your repayment goes to interest. Later, more goes to principal. This is why extra repayments made early can have an outsized impact.
Why extra repayments matter
Even small additional amounts can make a meaningful difference. If you pay just a little extra every month, you reduce the balance faster. A lower balance means less interest charged next period, which accelerates your progress.
- Potentially save thousands in interest.
- May shorten the loan by months or years.
- Improves flexibility if rates rise in future.
Practical tips when using the calculator
1) Stress-test your budget
Try an interest rate 1% to 2% higher than current offers. If repayment remains manageable, your plan is more resilient.
2) Compare terms carefully
A longer term lowers each regular repayment but usually increases total interest. A shorter term does the opposite. Use the calculator to compare trade-offs clearly.
3) Review repayment frequency
Weekly or fortnightly schedules can align better with pay cycles. In some cases, they may also improve repayment discipline.
Common mistakes to avoid
- Ignoring additional homeownership costs (insurance, taxes, maintenance, strata/HOA fees).
- Using a teaser interest rate instead of a realistic long-term rate.
- Not checking whether your loan allows fee-free extra repayments.
- Assuming every lender calculates interest and fees exactly the same way.
Final thoughts
A home loan repayment calculator is one of the easiest ways to make informed borrowing decisions. It turns a complex financial commitment into numbers you can plan around.
Use this estimate as a planning tool, then verify exact figures with your lender or mortgage broker. Product fees, offset accounts, redraw rules, and changing rates can all affect real-world outcomes.