AU Finance Tools

Australian Home Loan Calculator with Offset

Model your mortgage repayments in Australia with dynamic loan amount, interest rate, term, offset balance and extra repayments. See how much interest you save and how principal reduces over time.

How to use

Tap any field to select it and type your own number. Add an offset balance or extra repayment to see interest saved and years shaved off your loan.

$
% p.a.
yr
$

Money in your linked offset account reduces the balance interest is charged on.

$

Repayment (monthly)

$3,981.05

Total interest

$783,177

Total repaid

$1,433,177

Principal vs Interest

Loan balance over time

Estimates only. Actual repayments depend on your lender's calculation method, fees and interest rate changes.

How Australian home loan repayments work

A standard Australian home loan — also called a mortgage — is an amortising loan. That means each repayment covers both interest for the period and a portion of the principal. Interest is calculated daily on the outstanding balance and charged monthly. Over a typical 25 or 30 year term, most of your early repayments go to interest, and the split gradually shifts toward paying down principal. A good home loan calculator Australia borrowers can rely on shows you exactly when that crossover happens.

What is an offset account and why does it matter?

An offset account is a everyday transaction account linked to your home loan. The balance in it is subtracted from your loan balance each day before interest is calculated. So $50,000 sitting in an offset against a $500,000 loan means you're only charged interest as if you owed $450,000 — while still having full access to the cash. Offsets are one of the most powerful features of modern Australian mortgages because they cut interest without locking your money away.

Extra repayments: small changes, big savings

Because interest compounds on the outstanding principal, even modest extra repayments can save tens of thousands of dollars over the life of a loan and shave years off the term. Switching from monthly to fortnightly repayments effectively gives you a 13th monthly repayment each year, all of which goes straight to principal. Use the offset and extra repayment fields above to see the impact in your own numbers.

Fixed vs variable interest rates in Australia

Variable rate loans move with the market and the Reserve Bank of Australia's cash rate, so your repayments can go up or down. Fixed rate loans lock in a rate for a set period (commonly 1–5 years) giving certainty but usually with restrictions on extra repayments and offsets. Many Australians choose a split loan to get the best of both worlds.

How to use this home loan calculator

  1. Enter the loan amount you plan to borrow (or your current balance).
  2. Set the interest rate and loan term — use the sliders for quick what-ifs.
  3. Choose your repayment frequency: monthly, fortnightly or weekly.
  4. Add your offset balance and any extra repayments you plan to make each period.
  5. Review your repayment, total interest, principal vs interest split, and how your balance falls over time in the chart.

Frequently asked questions

+How does an offset account reduce interest?

Interest on a home loan is calculated daily on the outstanding balance. An offset account is a transaction account linked to your loan — the balance sitting in it is subtracted from the loan balance each day before interest is charged. So $50,000 in an offset on a $500,000 loan means interest is only charged on $450,000, without you needing to make an extra repayment.

+Is fortnightly or monthly better for a mortgage?

Paying fortnightly (using half the monthly amount every two weeks) means you make 26 payments a year — the equivalent of 13 monthly repayments instead of 12. That extra payment goes straight to the principal and can shorten your loan by several years and save tens of thousands in interest.

+How much can I borrow in Australia?

Lenders typically assess borrowing capacity using your income, existing debts, living expenses and a serviceability buffer (currently 3% above the loan rate under APRA guidance). A rough guide is 5–6× gross annual household income, but this varies significantly by lender and personal circumstances.

+What is the difference between principal and interest?

Principal is the amount you borrowed. Interest is what the lender charges you for borrowing it, calculated on the outstanding principal. Early in a loan, most of each repayment goes to interest; as the principal shrinks, more of each repayment goes to reducing principal.

+Do extra repayments really make a difference?

Yes — even small extra repayments have a large impact because they reduce the principal that future interest is charged on. On a typical 30-year loan, an extra $200/month can shave several years off the term and save tens of thousands in interest.