If you're researching a home loan and want a fast estimate of repayments, this Commonwealth Bank mortgage calculator replica can help. Enter your property price, deposit, interest rate, and term to estimate your repayments and total loan cost. You can also test extra repayments to see how much interest you may save over time.
What this mortgage calculator shows
This calculator is designed for principal-and-interest repayments and provides a practical snapshot of:
- Your estimated loan amount after deposit
- Loan-to-value ratio (LVR)
- Repayment amount by frequency (monthly, fortnightly, or weekly)
- Total interest over the full term
- Impact of extra repayments on loan duration and interest cost
How repayments are calculated
1) Standard amortisation formula
For most Australian home loans with principal and interest repayments, each repayment includes: a portion of interest and a portion of principal. Over time, the interest component decreases while the principal component increases.
The base repayment is calculated from loan amount, periodic interest rate, and number of repayments. This is the same general method used in most mortgage repayment calculators.
2) Extra repayment simulation
Extra repayments are simulated period-by-period. If you add an extra amount to each repayment, the balance falls faster, and less interest accrues. This often shortens the loan by years.
How to use this Commonwealth Bank mortgage calculator replica
- Enter the purchase price of the property.
- Enter your deposit amount.
- Set an annual interest rate.
- Choose your loan term (for example, 25 or 30 years).
- Select monthly, fortnightly, or weekly repayments.
- Add any extra amount you plan to pay regularly.
- Click Calculate Mortgage to view results.
Example scenario
| Input | Example Value | Why it matters |
|---|---|---|
| Property Price | $800,000 | Sets your borrowing target |
| Deposit | $160,000 (20%) | Reduces loan amount and LVR |
| Interest Rate | 6.29% p.a. | Major driver of repayment size |
| Loan Term | 30 years | Longer term lowers repayments but increases total interest |
| Extra Repayments | $100 per period | Can significantly cut total interest and term |
Ways to improve your borrowing position
Build a larger deposit
A bigger deposit lowers your loan amount and LVR. In many cases this can improve your rate options and reduce lender's mortgage insurance risk.
Compare variable and fixed-rate structures
Fixed rates give payment certainty for a period, while variable rates can move with market conditions. Some borrowers prefer split loans to balance certainty and flexibility.
Use extra repayments strategically
Even small recurring extra repayments can produce a meaningful long-term impact. Run multiple scenarios in this calculator to compare conservative and aggressive repayment plans.
Costs this calculator does not include
Mortgage repayments are only one part of total ownership cost. Consider additional expenses such as:
- Stamp duty and transfer fees
- Conveyancing/legal fees
- Building and pest inspections
- Council rates, strata fees, and insurance
- Maintenance and ongoing property costs
Frequently asked questions
Is this an official Commonwealth Bank calculator?
No. This page is an educational replica and is not affiliated with Commonwealth Bank. Always confirm final figures with your lender or broker.
Why are my results different from a bank quote?
Bank quotes may include rate discounts, fees, package pricing, offset account effects, and product-specific terms. This calculator provides an estimate only.
Should I choose weekly, fortnightly, or monthly repayments?
The best option depends on your cash flow pattern and lender setup. Many borrowers align repayments with salary frequency to make budgeting easier.