Mortgage Calculator Australia — Estimate Your Monthly Repayments
This article provides general information only and does not constitute financial advice. For advice tailored to your situation, consult a licensed financial adviser. Learn more.
Contents
Enter your loan amount, interest rate and loan term to calculate your estimated monthly, fortnightly and weekly mortgage repayments in Australia.
Mortgage Repayment Calculator
How to Use This Calculator
Enter three values:
- Loan amount — the amount you plan to borrow (not the purchase price). If you’re buying a $750,000 home with a $150,000 deposit, enter $600,000.
- Interest rate — enter the advertised rate for the loan you’re considering. Consider using the comparison rate for a more realistic estimate (see below).
- Loan term — most Australian home loans are 25 or 30 years. Shorter terms mean higher repayments but significantly less interest paid overall.
The calculator assumes principal-and-interest (P&I) repayments, which is how most owner-occupier home loans in Australia work. If you’re looking at interest-only repayments (common for investors), your monthly payment will be lower upfront — but you won’t be reducing your loan balance during the interest-only period.
Understanding Your Results
Monthly Repayment
This is the amount you pay each month to the bank. It covers both interest (the cost of borrowing) and principal (reducing your loan balance).
In the early years of your loan, most of your repayment goes towards interest. As you pay down principal, the interest portion shrinks and more of each payment chips away at your debt — this is called amortisation.
Fortnightly vs Monthly Repayments
Paying fortnightly rather than monthly is one of the simplest ways to reduce your loan term and save on interest. The reason: there are 26 fortnights in a year but only 12 months. Paying half your monthly repayment every fortnight results in 13 full monthly repayments per year rather than 12 — effectively one extra payment annually.
On a $600,000 loan at 6.00% over 30 years, switching from monthly to fortnightly repayments can reduce your loan term by approximately 3 to 4 years and save tens of thousands in interest. See our fortnightly vs monthly repayments guide for more detail.
Total Interest Paid
The total interest figure is often confronting. On a $600,000 loan at 6.00% over 30 years, total interest exceeds $690,000 — more than the loan itself. This underscores why:
- Paying extra even occasionally has a dramatic compound effect
- Refinancing to a lower rate can save hundreds of thousands over a loan’s life
- Shorter loan terms reduce total interest significantly
Repayment Tables by Loan Amount
The table below shows estimated monthly repayments at common loan sizes and interest rates on a 30-year principal-and-interest loan.
| Loan Amount | 5.50% p.a. | 6.00% p.a. | 6.50% p.a. | 7.00% p.a. |
|---|---|---|---|---|
| $300,000 | $1,703 | $1,799 | $1,896 | $1,996 |
| $400,000 | $2,271 | $2,398 | $2,528 | $2,661 |
| $500,000 | $2,839 | $2,998 | $3,160 | $3,327 |
| $600,000 | $3,407 | $3,597 | $3,792 | $3,992 |
| $700,000 | $3,975 | $4,197 | $4,424 | $4,657 |
| $800,000 | $4,542 | $4,796 | $5,056 | $5,322 |
| $900,000 | $5,110 | $5,396 | $5,688 | $5,987 |
| $1,000,000 | $5,678 | $5,996 | $6,321 | $6,653 |
Principal-and-interest, 30-year term, monthly repayments.
What Affects Your Mortgage Repayment?
1. Interest Rate
Your interest rate is the biggest driver of your repayment amount. A 1% difference in rate on a $600,000 loan changes monthly repayments by approximately $360–400 — and tens of thousands in total interest over 30 years.
Australian home loan rates are heavily influenced by the RBA cash rate. When the RBA raises or cuts the cash rate, variable home loan rates typically move within weeks. Fixed rates are set by individual lenders based on their funding costs and expectations of future rate movements.
As of publication, average variable owner-occupier rates sit in the 6.00–7.00% p.a. range. Always use the comparison rate (not the advertised rate) to compare loans — the comparison rate incorporates most ongoing fees.
2. Loan Term
Stretching your loan from 25 to 30 years reduces monthly repayments by around 10%, but dramatically increases total interest paid. Conversely, choosing a 25-year term increases repayments modestly but saves significantly overall.
| Term | Monthly repayment (6%, $600k) | Total interest |
|---|---|---|
| 20 years | $4,301 | $432,240 |
| 25 years | $3,866 | $559,800 |
| 30 years | $3,597 | $694,920 |
3. Loan Type — P&I vs Interest-Only
Principal and interest (P&I) loans require you to repay both interest and principal simultaneously. Your loan balance reduces over time and you build equity.
Interest-only (IO) loans require you to pay only the interest for a set period (typically 1–5 years for investors). Repayments are lower upfront, but your loan balance doesn’t reduce during the IO period. After the IO period ends, repayments jump as you revert to P&I over the remaining (shorter) term.
IO loans are common for investors but generally not suitable for owner-occupiers because you pay more total interest and build equity more slowly.
4. Repayment Frequency
As noted above, switching to fortnightly repayments delivers meaningful interest savings. Weekly repayments deliver a similar (slightly smaller) benefit.
How to Reduce Your Mortgage Repayments
There are several legitimate ways to lower what you pay:
1. Refinance to a lower rate — if your rate is above the market average, refinancing to a competitive lender could save hundreds per month. Use our refinancing savings calculator to see the potential saving.
2. Extend your loan term — refinancing to a longer remaining term reduces repayments but increases total interest. Use this carefully.
3. Switch to interest-only — only suitable for investors with a clear strategy. Not recommended for owner-occupiers.
4. Apply for hardship assistance — if you’re struggling, speak to your lender about hardship provisions. Lenders are required to consider genuine hardship applications.
How to Pay Your Mortgage Off Faster
Conversely, several strategies can shorten your loan and save interest:
- Extra repayments — even $200/month extra on a $600,000 loan at 6% can save over $70,000 in interest and cut 3+ years off your loan. Use our extra repayments calculator to model the saving.
- Offset account — keep your savings in an offset account linked to your mortgage. Every dollar in offset reduces the interest calculated on your loan. See our offset account calculator.
- Fortnightly repayments — as described above, adds the equivalent of one extra monthly payment per year.
- Lump sum payments — tax refunds, bonuses and windfalls applied directly to your loan can shave years off the term.
What Is a Comparison Rate?
The comparison rate is a single annual percentage rate that combines the advertised interest rate with most loan fees (application fee, annual fee, monthly account fee). It gives a more accurate picture of the true cost of a loan.
Example: A loan advertised at 5.75% p.a. might have a comparison rate of 6.12% p.a. after accounting for a $395/year annual fee.
Lenders are required by law (under the National Consumer Credit Protection Act 2009) to display comparison rates whenever they advertise a rate. Always compare using comparison rates, not advertised rates. For more, see our guide on comparison rates explained.
How Accurate Is This Calculator?
This calculator provides estimates based on a constant interest rate over the full loan term. In practice:
- Variable rates change when the RBA adjusts the cash rate
- Fixed rates revert to variable after the fixed period ends
- Lenders may change their standard variable rate (SVR) outside of RBA movements
- Fees, charges and redraw activity can affect your actual repayment
For a precise repayment schedule including amortisation, use your lender’s official calculator or ask your mortgage broker to run the numbers through their software.
FAQ — Mortgage Repayments Australia
What is the average mortgage repayment in Australia?
The average Australian home loan is approximately $600,000–620,000 (based on ABS housing finance data). At a 6.00% p.a. variable rate over 30 years, repayments are roughly $3,600–3,720 per month. See our average mortgage repayment guide for current figures.
Can I afford a $600,000 mortgage?
As a rough guide, lenders typically allow no more than 30–35% of gross income to service debt repayments. At 6.00% over 30 years, a $600,000 mortgage costs around $3,600/month ($43,200/year). You’d generally need gross income of at least $120,000–130,000 to comfortably service this — though lender servicing assessments use a 3% buffer above the actual rate (APRA’s serviceability buffer). Use our borrowing power calculator for a more detailed estimate.
How are mortgage repayments calculated?
Australian mortgage repayments are calculated using the standard loan amortisation formula: $M = P \times \dfrac{r(1+r)^n}{(1+r)^n - 1}$ where $P$ = principal, $r$ = monthly interest rate (annual rate ÷ 12), and $n$ = total number of monthly repayments (years × 12).
What happens to my repayments if interest rates rise?
If you are on a variable rate loan, your lender will typically increase your repayments within weeks of an RBA cash rate rise. On a $600,000 loan, each 0.25% rate increase adds approximately $90–95 per month. On a fixed rate loan, your repayments stay the same until your fixed period ends.
Can I make extra repayments on a fixed rate loan?
Yes, but most fixed rate loans cap additional repayments at $10,000–$20,000 per year. Exceeding this may incur break costs. Variable and split loans generally allow unlimited extra repayments.
Results are estimates only. Assumes a constant interest rate and principal-and-interest repayments. Actual repayments will vary. For advice tailored to your situation, speak with a licensed mortgage broker or financial adviser. You can find one through the ASIC financial advisers register or MoneySmart.