Mortgage Repayment Calculator
See what your mortgage repayments would actually look like, per week, per month and per year, and how much faster you could pay it off with extra repayments.
Your details
Your estimated repayment
$3,597
Repayment per week
$830
Repayment per month
$3,597
Total interest over the loan
$695,029
This calculator assumes a fixed interest rate and standard monthly amortization for the full loan term. It does not account for offset accounts, redraw, refinancing, or changes in rate, and is not financial advice.
How to use this calculator
- 1. Enter the amount you're borrowing (or your current loan balance), the interest rate, and the loan term in years.
- 2. If you're planning to pay more than the minimum each month, enter that amount to see the impact on your payoff time and interest.
- 3. The calculator shows your repayment per week, month and year, plus a year-by-year breakdown of principal versus interest.
How your mortgage repayment is actually calculated
Your repayment is calculated so that the same amount, paid every month for the full loan term, pays off both the interest charged and the amount you borrowed by the end of the term. This is called amortization. Early on, most of each repayment goes toward interest because your balance is highest. As the balance shrinks, more of each repayment chips away at the principal instead. On a standard 30-year loan, it's common for well over half your early repayments to be interest rather than principal, which is why the balance can feel like it's barely moving in the first few years even though you're paying on time every month.
Why extra repayments make such a big difference
Because interest is calculated on your outstanding balance, any extra repayment reduces the balance interest gets charged on for every remaining month of the loan, not just the month you paid it. That compounding effect is why even a modest extra amount, paid consistently, can cut years off a 30-year loan and save tens of thousands of dollars in interest. The earlier in the loan you start making extra repayments, the bigger the effect, since there are more remaining months for the reduced balance to keep saving you interest. Most Australian home loans allow extra repayments without penalty, but check your specific loan for any restrictions, some fixed-rate loans cap how much extra you can pay each year.
FAQ
Why is my repayment higher than what my bank advertised?
Advertised rates are often introductory or comparison rates that don't reflect your actual rate, which depends on your deposit size, credit history and whether you choose principal and interest or interest-only. Always check the specific rate on your approved loan.
What's the difference between principal and interest repayments?
A principal and interest (P&I) repayment reduces both what you owe and the interest charged, this is the default for most home loans. An interest-only repayment only covers the interest for a set period, so your balance doesn't reduce, and repayments usually jump once the interest-only period ends.
Does this calculator account for interest rate changes?
No, it assumes a fixed rate for the full loan term. If you're on a variable rate, your actual repayments will change whenever your lender moves their rates, run the calculator again with an updated rate to see the new figures.
How much extra should I pay to make a real difference?
Even $50-$100 extra per month on a typical mortgage can save years off the loan and thousands in interest, since the effect compounds every month it's in the loan. Try a few different amounts in the calculator to see what fits your budget.
Does paying weekly or fortnightly instead of monthly help?
It can, but the benefit usually comes from paying more per year, not from the frequency itself. Paying half your monthly repayment fortnightly means 26 fortnightly payments a year, the equivalent of 13 monthly payments instead of 12, which is effectively an extra repayment. Confirm with your lender exactly how they apply fortnightly payments.
Should I use an offset account or make extra repayments?
Both reduce the interest you're charged in a similar way, but an offset account keeps your money accessible, while extra repayments paid directly onto the loan may be harder to redraw depending on your lender. It's worth comparing both options, our offset account article covers this in more depth.
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Disclaimer
This calculator assumes a fixed interest rate and standard monthly amortization for the full loan term. It doesn't account for offset accounts, redraw, refinancing, rate changes, or lender fees, and repayment frequency conversions are simplified estimates. This tool provides estimates only, is not financial advice, and doesn't replace advice from a mortgage broker or your lender.