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Mortgage CalculatorCalculate repayments, total interest, and the impact of offset accounts and extra repayments.
Monthly Repayment
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Total Interest
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Total Amount Paid
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Loan Paid Off In
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Rate Stress Test +3%
P&I repayment at 9.0%
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Extra per month
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Total interest at +3%
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APRA requires lenders to assess your ability to repay at +3% above the loan rate.
Repayment Frequency Comparison
| Frequency | Repayment | Total Interest | Total Paid | Interest Saved | Time Saved |
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Loan Balance Over Time
| Period | Payment | Interest | Principal | Balance |
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A free Australian mortgage calculator that shows your repayment, total interest, and full amortisation schedule. Enter a direct loan amount or switch to Property Purchase mode to derive the loan from your purchase price and deposit — including stamp duty by state, live LVR, and an LMI estimate when your net deposit is below 20%.
Model the impact of an offset account, extra repayments, or a change in frequency (weekly, fortnightly, monthly) on your total interest and payoff date. The Rate Stress Test card shows what your repayments would look like at the current rate plus the APRA 3% serviceability buffer.
All calculations run locally in your browser. No data is sent to any server.
Your repayment uses the standard amortisation formula: P × r × (1+r)ⁿ / ((1+r)ⁿ − 1), where P is the loan balance, r is the per-period interest rate, and n is the total number of periods. For a 30-year loan at 6% paid monthly, r = 0.06/12 = 0.005 and n = 360.
The calculator uses indicative flat rates by state (NSW 3.9%, VIC 5.5%, QLD/WA/TAS/ACT 3.5%, SA 4.0%, NT 4.5%) applied to the purchase price. Real stamp duty uses sliding-scale brackets and varies by property type, first-home buyer concessions, and whether the property is a principal place of residence or investment. Override the field manually if you have a precise figure. Stamp duty is deducted from your deposit to show the net deposit available for the loan — if stamp duty exceeds your deposit, the loan is the full purchase price.
Loan-to-Value Ratio (LVR) is your loan amount divided by the property value, expressed as a percentage. When LVR exceeds 80% — meaning your net deposit (after stamp duty) is less than 20% — most lenders require Lenders Mortgage Insurance (LMI). LMI protects the lender (not you) if you default. The premium is added to your loan and estimated here using indicative rates: 0.65% for 80–85% LVR, 1.27% for 85–90%, 2.43% for 90–95%, and 3.85% above 95%. Actual LMI varies by lender and insurer.
APRA requires lenders to assess whether you can still afford repayments at your interest rate plus a 3% buffer. The stress test card shows what your P&I repayment would be at that higher rate, how much extra that is per period compared to your current payment, and the total interest you'd pay over the life of the loan at that rate. It's a useful guide for your own financial resilience planning, not a lender assessment.
An offset account is a transaction account linked to your mortgage. Its balance reduces the principal on which interest is charged each period — a $500,000 loan with a $50,000 offset pays interest on only $450,000. The loan balance is unchanged; you're reducing the effective amount on which interest accrues. This calculator models 100% offset, which is standard for most Australian variable-rate loans.
Yes — because you make the equivalent of 13 monthly payments a year rather than 12. A fortnightly repayment is half the monthly amount paid 26 times, which equals one extra monthly payment annually. That extra principal reduces the balance sooner, cutting total interest. The frequency comparison table shows exactly how much you save and how many years earlier you pay off.
Interest-only loans are common for investment properties where the investor wants to maximise cash flow or tax deductions in the short term. During the IO period you pay no principal, so the balance doesn't decrease. Once the IO period ends, your P&I repayments are recalculated on the full original balance over the remaining term — meaning they'll be higher than if you'd been repaying principal from day one.
Yes, free with no sign-up required. Your inputs are saved only in your browser's localStorage so the calculator remembers them between visits. Nothing is sent to any server.