Make the most of spare cash: Lump Sum Calculator

What can you do with a lump sum calculator? Find out how you could pay off your home loan faster and pay less interest, with our Canstar Lump Sum Calculator.

A lump sum is a type of extra repayment made after the establishment of the loan, and is paid at the same time as you continue to make your regular monthly repayments.

You can do any number of calculations about lump sum repayments you could make on a home loan with the Canstar Lump Sum Calculator. Read on to find out how your loan term and the interest you pay are affected by making lump sum repayments of different sizes.

Find out how you can pay less interest and pay off your home loan faster with Canstar’s Home Loan Lump Sum Calculator.

How we made our calculations

The calculations we’ve made are based on inputting the following data into our calculator, except where we have specified otherwise.

  • Loan Amount: $350,000
  • Repayment Frequency: Monthly
  • Interest Rate: 89% (average standard variable interest rate on our database at time of writing)
  • Loan Term: 25 years
  • Lump sum: $1,000

According to Canstar’s comprehensive research database, the majority of Australians (60%) are looking for a loan amount of between $350,000 and $749,000 – so we’ve based our home loan calculations for this article on a loan of $350,000. You can enter the specific loan amount you are looking for in our home loan calculators and our comparison of home loans on the market.

Make sure you check whether the features of a home loan include the facility to make lump sum repayments, before signing up for the long haul.


How much you can afford to pay towards your loan is dependent on your personal financial situation, which will differ from the figures we have used in this calculation. You should carefully consider your own income and expenses when entering lump sum repayments into our calculator.

Canstar makes no guarantees that your financial institution of choice will allow you to make lump sum repayments of a certain amount, and you should speak with a financial adviser before making any decisions.

When to make a lump sum repayment

The short answer is that making a lump sum repayment as early as possible into the life of your loan will make the greatest difference to reducing the interest you pay on your loan.

The longer answer is that it is most helpful to make a lump sum repayment when you can afford to without injuring your emergency savings, and when your financial institution will not charge you a fee to do so.

The following table uses a lump sum of $1,000. Making a lump sum payment 5 years into your loan could save you $5,000 more in interest than making a lump sum payment after 10 years. Please note that this assumes that you continue making the same monthly repayment!

Home loan calculators to help you work out your financial position

Use CANSTAR’s home loan calculators when you’re doing your sums about how much you can afford to borrow in a home loan:

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