Finance Calculator — Australia

Your Australian mortgage, broken down to the dollar

Calculate repayments, stamp duty by state, and exactly how much extra repayments save. The most comprehensive free mortgage calculator in Australia.

💡At 6.5% over 30 years, you'll pay $765,267 in interest

Used by 50,000+ users monthly · No sign-up required · Instant results

Mortgage inputs

Property price$750,000

Deposit20%

Interest rate (p.a.)6.5%

Loan term30 years

Annual property tax$3,000

Extra repayment/month$0

State / territory

Monthly repayment

$4,192

P&I + tax + insurance

Principal + interest

$3,792

Loan repayment only

Total interest

$765,267

Over 30 years

Stamp duty

$28,485

NSW estimate

Deposit

$150,000

20% of price

Total upfront

$178,485

Deposit + stamp duty

💡

Adding would save you approximately $240,674 in interest.

Amortisation chart

PrincipalInterest

Monthly payment breakdown

Principal & Interest

$3,792

Property tax (est.)

$250

Insurance (est.)

$150

How Australian mortgage repayments are calculated

Standard Australian home loans use principal and interest (P&I) repayments. Each monthly payment covers both the interest charged for that period and a portion of the loan principal. The formula is:

M = P × [r(1+r)ⁿ] / [(1+r)ⁿ–1]
P = loan amount, r = monthly rate, n = number of payments

Example: $600,000 at 6.5% over 30 years: monthly rate = 6.5%/12 = 0.542%. Monthly repayment = $3,792.

Interest-only loans

Some borrowers (particularly investors) choose interest-only periods of 1–5 years, during which repayments are lower but the principal doesn't reduce. At the end of the IO period, repayments jump significantly as the remaining term is now shorter for the same principal.

The power of extra repayments

Extra repayments are one of the most effective strategies for Australian homeowners. Every dollar paid above the minimum directly reduces your principal — which reduces the interest charged in every subsequent period.

On a $600,000 loan at 6.5% over 30 years, an extra $500/month saves:

Interest saved

$167,000+

Years saved

8 years

Use the Extra repayment/month slider in the calculator above to model your exact savings. The amortisation chart updates in real time to show your accelerated payoff date.

Offset accounts vs extra repayments

An offset account achieves a similar interest reduction but keeps your cash accessible. Extra repayments permanently reduce the principal (unless you have a redraw facility). Both strategies are mathematically equivalent in their interest-reduction effect.

Lenders Mortgage Insurance (LMI) explained

LMI is required when your deposit is less than 20% of the property value (LVR above 80%). Despite the name, LMI protects the lender — not you. It covers the lender's loss if you default and the property sells for less than the outstanding loan amount.

LMI can be substantial — typically 1–4% of the loan amount depending on your LVR. On a $600,000 loan at 90% LVR, expect to pay $10,000–$15,000 in LMI, which is usually capitalised into the loan.

Some professions (doctors, lawyers, accountants) qualify for LMI waivers at up to 90% LVR with certain lenders. The government's First Home Guarantee allows eligible FHBs to borrow up to 95% without LMI. Use our LMI calculator for a detailed estimate.

Australian mortgage rates and APRA's role

The Reserve Bank of Australia (RBA) sets the cash rate, which influences but doesn't directly control mortgage rates. Australian lenders typically price variable mortgages at cash rate + 2–3%, while fixed rates are priced off wholesale funding costs and swap rates.

APRA (Australian Prudential Regulation Authority) requires lenders to assess borrowers at a minimum 3% above the actual loan rate. This serviceability buffer ensures borrowers can withstand rate increases — which is why your borrowing power is significantly lower than what you'd calculate at the current rate alone.

For a complete affordability check on a specific property — including borrowing power, LMI, stamp duty, and an AI verdict — use HomeVerdict.

Frequently asked questions

Australian home loan repayments use the standard amortisation formula: M = P × r(1+r)^n / ((1+r)^n − 1). Here P is the loan amount (property price minus deposit), r is the monthly interest rate (your annual rate divided by 12), and n is the total number of monthly repayments. For a $600,000 loan at 6.5% over 30 years: r = 0.065/12 = 0.005417, n = 360, giving M = $3,792/month. Over the full term you'd pay approximately $765,000 in interest alone — more than the original loan. This is why extra repayments and making fortnightly (instead of monthly) payments can save tens of thousands. Most Australian lenders allow you to choose between principal & interest (P&I) and interest-only (IO) repayments. P&I repayments are shown here — the standard choice that actually pays off your loan. Interest-only periods are common for investment properties, but defer principal reduction.

Stamp duty (also called transfer duty) is a state government tax on property purchases. It varies significantly by state and property value. On a $750,000 property: NSW charges approximately $29,235; VIC approximately $40,070; QLD approximately $24,525; WA approximately $28,390. First home buyers in most states are eligible for stamp duty concessions or exemptions. In NSW, first home buyers pay no stamp duty on properties up to $800,000 (as of 2024). VIC offers similar concessions. Always check your state revenue office for the most current thresholds and your eligibility. Use the state selector in this calculator to see the exact stamp duty for your situation. Note that stamp duty is a large upfront cost on top of your deposit — factor it into your savings plan alongside conveyancing fees, building inspection costs, and lender fees.

The minimum deposit at most Australian lenders is 5–10% of the purchase price, but borrowing more than 80% of the property value (loan-to-value ratio above 80%) triggers Lenders Mortgage Insurance (LMI) — an additional cost that can run $10,000–$30,000 or more on larger loans. A 20% deposit is the standard target that avoids LMI entirely. On a $750,000 property, that's $150,000 in deposit plus stamp duty and other costs — commonly $180,000–$200,000 in total savings required. Government schemes like the First Home Guarantee allow eligible buyers to purchase with just a 5% deposit without paying LMI, with the government guaranteeing up to 15%. Check eligibility on the Australian Government's Housing Australia website.

Fixed rate loans lock your interest rate for 1–5 years, giving payment certainty but usually preventing extra repayments beyond a cap (often $10,000/year). Variable rate loans move with the RBA cash rate and typically allow unlimited extra repayments with no penalty. In the current environment (2025), many borrowers choose a split loan — fixing a portion (e.g. 50–70%) for rate certainty while keeping the rest variable for flexibility and extra repayment capability. This balances predictability against the optionality of paying down debt faster. A 0.5% rate difference on a $600,000 loan over 30 years is approximately $60,000 in total interest — so rate comparison is worth doing carefully. Always compare the comparison rate, not the headline rate, which includes most fees.

Extra repayments on a home loan have a compounding effect because they reduce your principal balance, which lowers the interest calculated each month. On a $600,000 loan at 6.5% over 30 years, adding just $500/month extra saves approximately $190,000 in interest and cuts 9 years off the loan term. Even small extra amounts add up significantly over a 30-year term. An extra $200/month saves around $85,000 and cuts 4 years. The earlier you start making extra repayments, the greater the impact — because you're reducing the principal when it's at its highest. Fixed rate loans often cap extra repayments at $10,000–$20,000/year. Variable rate loans typically allow unlimited extra repayments. If your fixed loan allows it, maximising extra repayments within the cap during the fixed period is usually worthwhile.

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