Mortgage Calculator Guide
How to use mortgage calculators effectively for planning
In this guide
Why Use Mortgage Calculators?
Mortgage calculators help you understand your borrowing capacity, compare options, and plan your finances before applying for a loan. They're essential tools for making informed decisions.
Types of Calculators
Planning Calculators
- • Borrowing power calculator
- • Deposit savings calculator
- • Rent vs buy calculator
- • First home buyer eligibility
Loan Calculators
- • Repayment calculator
- • Extra repayment calculator
- • Refinance calculator
- • Split loan calculator
Cost Calculators
- • Stamp duty calculator
- • LMI calculator
- • Upfront costs calculator
- • Break cost calculator
Comparison Tools
- • Loan comparison calculator
- • Fixed vs variable calculator
- • Interest only vs P&I
- • Investment property calculator
Borrowing Power Calculator
This calculator estimates how much you can borrow based on your income, expenses, and existing debts.
What You'll Need
- ✓ Annual income (before tax)
- ✓ Other income sources
- ✓ Living expenses
- ✓ Existing loan repayments
- ✓ Credit card limits
- ✓ Number of dependents
Understanding Results
Important Notes:
- • Results are estimates only
- • Actual borrowing may be 10-20% different
- • Each lender has different criteria
- • Doesn't include upfront costs
Pro Tips
- Include all income sources (rental, investments, bonuses)
- Be realistic with expenses - lenders use benchmarks
- Credit card limits count as debt even if paid off
- Consider closing unused credit cards before applying
- Factor in rate rises - can you afford 2-3% higher?
Repayment Calculator
Calculate your regular loan repayments based on loan amount, interest rate, and loan term.
Key Inputs
Basic Inputs
- • Loan amount
- • Interest rate
- • Loan term (years)
- • Repayment frequency
Advanced Options
- • Extra repayments
- • Offset account balance
- • Interest only period
- • Fees and charges
Example Scenarios
| Loan Details | Monthly Payment | Total Interest |
|---|---|---|
| $400k @ 6% for 30 years | $2,398 | $463,353 |
| $400k @ 6% for 25 years | $2,578 | $373,376 |
| $400k @ 5.5% for 30 years | $2,271 | $417,625 |
Impact of Extra Repayments
Adding just $100/month extra to a $400,000 loan at 6%:
- • Saves $51,874 in interest
- • Reduces loan term by 3 years 8 months
- • Total savings increase with larger extra payments
Comparison Calculator
Compare different loan options side-by-side to find the best deal.
What to Compare
Rate Features
- Interest rate vs comparison rate
- Fixed vs variable options
- Introductory rates vs ongoing
- Professional package discounts
Costs & Features
- Application and ongoing fees
- Offset account availability
- Redraw facility
- Extra repayment options
Comparison Example
Comparing two $500,000 loans:
Option A: Lower Rate
- Rate: 5.8%
- Fees: $395/year
- No offset account
- Total cost over 5 years: $143,245
Option B: More Features
- Rate: 5.95%
- Fees: $0 (package)
- 100% offset account
- Total cost over 5 years: $145,123*
*Could be lower with offset account usage
Stamp Duty Calculator
Calculate the government stamp duty payable on your property purchase.
Key Factors
- State/Territory: Each has different rates and thresholds
- Property value: Higher values = higher rates
- Property type: Investment properties often higher
- Buyer type: First home buyers may get concessions
- Property use: Primary residence vs investment
State Variations Example ($600,000 property)
| State | Owner Occupied | First Home Buyer |
|---|---|---|
| NSW | $22,490 | $0* |
| VIC | $31,070 | $15,535 |
| QLD | $15,925 | $0* |
*Subject to eligibility criteria
Calculator Tips
Getting Accurate Results
- Use current interest rates, not advertised rates
- Include all fees in comparisons
- Factor in your actual tax rate for investment properties
- Update inputs as your situation changes
- Consider multiple scenarios (rate rises, income changes)
Common Calculator Mistakes
- ❌ Using gross income instead of net
- ❌ Forgetting about ongoing costs
- ❌ Not including all debts
- ❌ Ignoring lender-specific policies
- ❌ Assuming calculator results = approval
Advanced Strategies
- 📊 Create spreadsheets with multiple scenarios
- 📊 Model the impact of offset accounts
- 📊 Calculate break-even points for refinancing
- 📊 Compare total cost over expected ownership period
- 📊 Factor in opportunity cost of deposits
Find Your Perfect Mortgage in Minutes
Our RateReviewGuide Assistant analyzes your financial situation and instantly matches you with the best home loan options from Australia's top lenders.
No commitment required • Free to use • Results in seconds
Calculator Checklist
Before House Hunting
- ✓ Borrowing power calculator
- ✓ Stamp duty calculator
- ✓ Upfront costs calculator
Before Applying
- ✓ Repayment calculator
- ✓ Comparison calculator
- ✓ LMI calculator (if needed)
Disclaimer: Calculator results are estimates only and should not be relied upon as accurate. Actual loan amounts, repayments, and costs will vary based on lender policies and individual circumstances. Always seek professional financial advice.