Mortgage Repayment Calculator With Extra Repayments

A mortgage repayment calculator with extra repayments lets you see how paying more than the minimum on your home loan can reduce the amount of interest costs and your loan term. Instead of just showing your standard repayment, it models extra repayments, lump sums and offset account balances so you can compare different strategies side by side, before you commit.

Many Australian banks and lenders now provide extra repayment tools or combined home loan repayment and offset calculators that estimate how extra contributions change your total interest and years on the loan.

A well-designed mortgage repayment calculator with offset account and extra payments goes a step further by showing you the impact of:

• Regular weekly, fortnightly or monthly extra repayments

• One-off lump sum payments

• Different balances sitting in your offset account

• Changes to your interest rate or loan term

This gives you a clearer picture of how to pay off your mortgage sooner without guessing.

How a mortgage calculator with offset and extra repayments works

Most mortgage calculators with extra repayments use a few key inputs:

• Loan amount – how much you owe (or plan to borrow)

• Interest rate – fixed, variable or a blended rate

• Loan term – usually 25–30 years in Australia

• Repayment frequency – weekly, fortnightly or monthly

• Extra repayments – how much extra you’ll pay and from what year

• Offset account balance – how much you’ll usually keep in your offset account

Behind the scenes, the loan repayment calculator runs an amortisation schedule, just like many lender and comparison site tools do. It shows you:

• Standard minimum repayment

• New repayment or term once extra repayments or offset are applied

• Total interest paid to reduce the life of the loan

• Interest saved and time saved compared to doing nothing

A mortgage extra repayment calculator with offset combines these ideas so you can see whether putting spare cash into the loan, into your offset, or a mix of both gives you the best outcome.

While the calculator uses standard amortisation formulas, it does not assess individual lender lending criteria such as income verification, credit history, loan type restrictions or repayment limits, which can vary between Australian banks and lenders.

Why make extra repayments on your home loan?

Extra repayments can dramatically change the long-term cost of your mortgage. Even small amounts, especially in the first years of the loan, can shave years off and save thousands in interest.

Using a mortgage repayment calculator with extra payments helps you:

• Visualise the impact of paying an extra $20, $50 or $200 a week

• See how much sooner you could be debt-free

• Understand how much of your repayment is going to interest vs principal

• Decide whether to keep cash in savings, offset or pay it straight off the loan

Once you see the potential savings, it’s easier to decide if it’s worth refinancing to a sharper rate, switching to a loan with better features, or setting up a new offset account. Many Australian lenders highlight these benefits alongside their extra repayment calculators.

Here is an example of how much you can save on your home loan

Below we have a home loan of $400,000, with an additional repayment of $500 per month, on top of the minimum required repayment of $2,207 per month. Making an additional payment of $500 per month, will save  you 10 years and 2 months of the 30 year loan term, as well as $150K in interest, so it pays to make any additional repayments you can afford to repay into the loan.

You can use our free additional repayment calculator at the bottom of this page to estimate how much you can save on your home loan.

Offset account vs extra repayments: what’s the difference?

A home loan offset account is a transaction or savings account linked to your mortgage. The money in this account is “offset” against your loan balance, so you only pay interest on the difference.

• Extra repayments permanently reduce your loan balance

• Money in an offset account reduces interest while it sits there, but can still be withdrawn if needed

A mortgage calculator with offset and extra repayments helps you compare:

• Putting spare cash directly onto the loan

• Parking your money in an offset account

• Using a mix of extra repayments plus a consistent offset balance

For example, some Australian calculators show how a $400,000 loan with $50,000 in offset only charges interest on $350,000, helping you pay the loan down faster without losing access to your cash.

Which strategy is best depends on:

• Whether your loan has redraw and any redraw fees

• Your need for access to funds (for emergencies, renovations, investing)

• Any limits or penalties on extra repayments, especially for fixed-rate loans

How to use a mortgage repayment calculator with extra repayments

Use this simple process to get the most from your calculator:

1. Enter your current loan details
   Loan amount, interest rate, remaining term and repayment frequency.

2. Check your baseline
   Note your standard repayment, total interest and estimated end date.

3. Add regular extra repayments
   Try adding an extra weekly or fortnightly amount. A good mortgage repayment calculator with extra repayments will instantly show you the new total interest and loan term.

4. Layer in lump sums
   Add a tax refund, bonus or inheritance as a one-off payment and see how much more interest and time you can save.

5. Include your offset account
   If you have (or plan to have) an offset account, enter an average balance. A mortgage repayment calculator with offset account and extra payments will show how combining both strategies improves your results.

6. Compare scenarios
   Run a few versions:

   • Extra repayments only

   • Offset only

   • Offset + extra repayments

   • Refinancing to a lower rate with the same extras

7. Talk to a broker or lender
   Once you know what’s possible, a broker can confirm which loan products let you make unlimited extra repayments, access a 100% offset account, or refinance to a sharper rate that fits your goals.

When should you use a mortgage calculator with extra repayments?

A mortgage repayment calculator with extra repayments or mortgage repayment calculator with offset account and extra payments is especially useful if:

• You’re planning to refinance and want to see the benefit of a better rate plus extras

• Your income has increased and you can now pay more each month

• You receive regular bonuses, commissions or overtime

• You’re deciding between opening an offset account or just increasing repayments

• You’re a property investor modelling different repayment strategies on multiple loans

Because extra repayments in the early years of a loan have the biggest impact on interest, the sooner you start modelling scenarios, the more savings you can unlock.

If you’re not sure how much extra you can afford to pay, or whether offset, redraw or lump sums will work best for you, a calculator is only the first step. A home loan specialist or mortgage broker can look at your personal circumstances and review your income, living expenses, tax position and goals, then recommend a loan and repayment strategy tailored to you.

Use the calculator to explore your options, then reach out for personalised advice before you make changes to your loan.