Disclaimer: This calculator is provided for general information only and does not take into account your personal objectives, financial situation or needs. It is not credit advice. You should obtain and consider the relevant Product Disclosure Statement (PDS) and seek independent, professional advice before making any decisions.
Our Australia mortgage calculator uses industry-standard formulas adapted for Australian mortgage practices to provide accurate payment estimates. All calculations follow ASIC guidelines and include proper regulatory compliance features.
1. Principal and Interest Calculation
The core of your mortgage payment uses the standard amortization formula:
Where:
- P = Principal loan amount (property price - deposit)
- r = Periodic interest rate (varies by payment frequency)
- n = Total number of payments (years × payments per year)
Payment Frequency Handling
Our calculator supports multiple payment frequencies with accurate rate conversion:
- Monthly: Annual rate ÷ 12 (nominal rate approach)
- Fortnightly: Annual rate ÷ 26 (nominal rate approach)
- Weekly: Annual rate ÷ 52 (nominal rate approach)
Loan Types
- Principal & Interest: Standard amortization formula
- Interest Only: Periodic payment = Principal × Periodic rate
2. Row-by-Row Rounding (Accounting Best Practice)
For maximum accuracy, our calculator uses row-by-row rounding:
- Each period's interest is rounded to 2 decimal places
- Each period's principal is rounded to 2 decimal places
- Each period's balance is rounded to 2 decimal places
- Total interest and principal are derived from summing the rounded schedule rows
3. Council Rates and Insurance
Annual costs are properly distributed based on your payment frequency:
Examples:
- Monthly: Annual cost ÷ 12
- Fortnightly: Annual cost ÷ 26
- Weekly: Annual cost ÷ 52
4. LMI (Lenders Mortgage Insurance)
LMI is required when your loan-to-value ratio exceeds 80%:
Note: Actual LMI premiums depend on lender, LVR and loan size—contact your lender for a quote.
5. Stamp Duty Calculation
State-specific stamp duty calculation based on property value and state:
Note: State stamp duty varies—this is an estimate only. First home buyer concessions may apply.
6. Application Fees
One-time fees charged by the lender for processing your loan application.
7. Extra Payments
Our calculator handles additional payments to help you pay off your loan faster:
- Extra Periodic Payment: Additional amount paid each period
- One-time Payment: Lump sum payment in the first period
Extra Payment Impact
Extra payments are applied to reduce the principal balance, which:
- Reduces the total interest paid over the loan term
- Shortens the loan duration
- Creates a new amortization schedule
8. Total Cost Calculation
The total cost includes all components:
Where:
- Property Price: Purchase price of the property
- Total Interest: Sum of all interest payments over loan term
- LMI: Lenders Mortgage Insurance (if applicable)
- Stamp Duty: State transfer duty
- Application Fee: Lender processing fee
Australia-Specific Features
Regulatory Compliance
- ASIC RG 87 Compliance: Proper disclaimers and disclosures
- National Credit Code: Comparison rate footnotes
- Key Facts Panel: Indicative-only labeling
- No Credit Advice: Clear informational purpose statements
Comparison Rate
The comparison rate includes most fees and charges to help you compare loans:
Warning: Comparison rate based on a $150,000 loan over 25 years. This comparison rate applies only to the example given.
First Home Buyer Considerations
- Stamp duty concessions in most states
- First Home Owner Grant (FHOG) eligibility
- Reduced LMI premiums for some lenders
9. Amortization Schedule Generation
Our calculator generates a detailed payment-by-payment breakdown:
- Payment Number: Sequential payment identifier
- Payment Amount: Total payment for the period
- Principal: Amount applied to loan balance
- Interest: Interest charged for the period
- Balance: Remaining loan balance
- Extra Payments: Additional amounts applied
10. Export Functionality
Our calculator provides comprehensive export capabilities:
CSV Export Features
- Summary Section: Property details, loan amounts, rates
- Loan Terms: Interest rates, comparison rates
- Periodic Costs: Complete payment breakdown
- Total Costs: Full cost analysis over loan term
- Extra Payment Analysis: Savings and term reduction
- Amortization Schedule: Full payment-by-payment breakdown
- Regulatory Notes: ASIC compliance and disclaimer information
Professional Format
- Excel-compatible CSV format
- Proper currency formatting ($)
- Detailed payment breakdown
- ASIC compliance notes
- Legal disclaimers included
11. Input Validation and Edge Cases
Our calculator handles various edge cases and validates inputs:
- Property Price Range: $50,000 to $10,000,000+
- Interest Rate Range: 1.00% to 15.00%
- Deposit Validation: Minimum 5% for most lenders
- Loan Term Options: 15, 20, 25, or 30 years
- Payment Frequency: Weekly, fortnightly, or monthly
12. Currency and Formatting
All calculations use Australian dollar formatting:
- Currency Symbol: AUD $
- Decimal Places: 2 for currency amounts
- Thousands Separator: Comma (e.g., $1,234.56)
- Rounding: Standard banking rounding rules
13. Performance and Accuracy
Our calculator is designed for:
- Real-time Calculation: Instant results as you type
- High Accuracy: Industry-standard formulas
- Comprehensive Coverage: All major Australian mortgage features
- Mobile Responsive: Works on all devices
Important: This calculator provides estimates for planning purposes only. Actual loan terms, rates, and fees may vary significantly between lenders. Always consult with your lender for exact payment amounts and terms.