
Buying a home is one of the biggest financial decisions most Australians make.  
Before signing up for a loan, it helps to know what your repayments will look like — and how small tweaks can make a big difference over time.

That’s where a **mortgage repayment calculator** comes in. It lets you estimate your repayments, total interest, and potential savings from extra payments — all before you apply.

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## Table of contents
1. [What you’ll need](#what-youll-need)
2. [Step-by-step guide](#step-by-step-guide)
3. [Understanding your results](#understanding-your-results)
4. [Common mistakes to avoid](#common-mistakes-to-avoid)
5. [Smart ways to save](#smart-ways-to-save)
6. [The bottom line](#the-bottom-line)

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## What you’ll need

To get started, gather a few key details:

- **Loan amount** – for example, $650,000  
- **Interest rate** – fixed or variable  
- **Loan term** – typically 25–30 years  
- **Repayment frequency** – weekly, fortnightly, or monthly  
- Optional: **extra repayments** or an **offset balance**

These inputs form the basis for your loan projection.

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## Step-by-step guide

1. Open the **[Mortgage Calculator](/calculators/mortgage)**.  
2. Enter your loan amount, interest rate, and term.  
3. Choose between **principal & interest** or **interest-only**.  
4. Switch repayment **frequency** to compare how totals change.  
5. Add **extra repayments** to see how much time and interest you can save.

> **Tip:** Paying fortnightly can effectively add one extra month’s worth of repayments each year, helping you pay off the loan faster — without feeling the difference.

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## Understanding your results

The calculator shows more than just your repayment amount. You’ll see:

- **Repayment amount** – what you’ll pay each period  
- **Total interest** – how much you’ll pay over the life of the loan  
- **Loan end date** – when you’ll be mortgage-free  
- **Amortisation schedule** – how much of each payment goes to principal vs interest  

This breakdown helps you see where your money goes — and how even small extra repayments can save thousands.

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## Common mistakes to avoid

A calculator gives estimates, not approvals. Avoid these common pitfalls:

- Forgetting to include **fees** or **Lenders Mortgage Insurance (LMI)**  
- Comparing **fixed vs variable** without checking **break costs**  
- Assuming an **introductory rate** lasts for the entire term  

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## Smart ways to save

Once you understand your baseline, try running a few scenarios:

- Add **$50 extra per week** to see how quickly the term shortens  
- Reduce the **loan term** for faster equity growth  
- Use an **offset account** to lower interest without locking away savings  
- Model a **0.50% rate rise** to test your budget resilience  

> Even small changes — like rounding repayments up to the nearest $10 — can shave years off your mortgage.

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## The bottom line

A mortgage calculator won’t replace financial advice, but it’s an excellent way to take control.  
It helps you plan, test scenarios, and prepare for different interest rate environments before meeting with a lender or broker.

**Ready to run the numbers?**  
Try the [Mortgage Calculator](/calculators/mortgage) and see how adjusting your repayments, frequency, or extra payments could save you thousands over the life of your loan.

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A step-by-step guide to estimating home loan repayments in Australia — including repayment frequency, extra payments, and the difference between interest-only and principal & interest loans.

#home loan

How to Use a Mortgage Repayment Calculator (Australia 2025 Guide)