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Lump Sum Repayment Calculator

Rates and Fees verified correct on January 19th, 2017

Find out how much a lump sum payment will save you in interest

When you make a regular payment on a home loan, some goes towards the interest component and some goes towards the loan amount still owing, so your gradually pay off your home loan in the term you agree to. When you make a lump sum payment, sometimes you can get ahead on your repayments by months or even years, as a much large payment goes towards your home loan rather than interest. Using the calculator below you can see just how much of an impact these payments can have.

A lump sum calculator can help you figure out how paying a lump sum on your mortgage can affect the overall loan. The calculator is simple to use and can help you better manage your current loan or help you figure out your repayment options when looking for a new loan.

Lump sum calculators are a great tool to have if you happen to come into extra money during the year, like an unexpected bonus/raise or a tax return and you want to see how much they could reduce your home loan interest. As long as you know the size of your loan, the term, the repayment schedule and your interest rate you can figure out how different lump sum payments will affect your mortgage.

How to use the lump sum calculator


In order to use a lump sum calculator you’ll need certain details regarding your loan and the payment you’re looking to make. You’ll first need your original loan amount, the term of the loan, the interest rate you’re paying on the loan and how often you make repayments on the loan. You’ll also need the total amount of money you’re looking to pay towards your mortgage and the starts after date (in years).

Once you input all of the necessary information into the calculator you’ll be able to see the results right away and figure out if putting a lump sum toward your mortgage will be worth it in terms of savings. Usually a lump sum payment will go toward your principal more so than interest, which will help you pay down your loan faster than just making general repayments.

  • Your loan amount. This is the amount of money you originally borrowed.
  • The loan term. This refers to the length of time the loan is for.
  • The interest rate. This is the agreed upon amount of interest that is attached to your mortgage, expressed as a percentage.
  • The repayment frequency. This is how often you make scheduled repayments toward the mortgage. This can be weekly, fortnightly, or monthly, depending upon your agreement with your lender.

Case study

Susan just inherited some money unexpectedly. Since she is looking for a responsible way to use her new-found money she decides to take some of it and pay a lump sum toward her mortgage. She knows that by doing this she’ll save some money on the interest rate of her loan and take some time off her loan term. In order to figure out exactly what a lump sum will do for her mortgage she uses a lump sum calculator.

After she gathers all of her information and opens the loan calculator and then enters in her information into the designated fields. Susan inputs her original loan amount, $300,000. She then inputs her interest rate (5.5%), her loan term (20 years) and her repayment frequency (monthly).

Susan then has to input her lump sum information. She is looking to put down $10,000 and has had her mortgage for two years. According to the calculator, Susan has been making monthly payments of $2,063.66 a month and has a remaining balance of $282,571 after two years. If she were to put a lump sum of $10,000 toward her loan she’ll save $16,141 on interest and take a year off her loan.

Frequently asked questions

What information will I need to use the calculator?

When using any calculator you won’t need any personal details like your name, date of birth, or address. All you need for the lump sum calculator is the original amount of money you borrowed, the loan term, the agreed upon interest rate, your repayment frequency, the amount of the lump sum you’re looking to pay, and finally how long you’ve had the mortgage (the start after date).

How do lump sum payments work?

Lump sum payments are large payments that you make toward your loan. This is in addition to your scheduled repayments. They are a way to pay your loan down faster as they go toward your principal instead of your interest. Since this payment will lower your principal it will cause your interest to go down as well since that rate is based on the size of the principal amount.

How accurate is the calculator?

The calculator uses all of the information you put into it to create an accurate result. There is no guessing involved, and it works purely by calculations.

What should I look for when making a lump sum payment?

Always check the terms of your loan before making a lump sum payment toward your mortgage as you may be charged a fee for paying an additional repayment. If these penalties are built into the loan it might not be worth it to make this payment. You should also to check out other options that may be more beneficial, like putting the money into a 100% offset account.

Lump sum calculators can help take the guess work out of loan repayments and allow you to see what affects a lump sum payment will have on your overall loan. If you’re looking to make a lump sum payment toward your mortgage or would like to see if this kind of payment is worth doing, try out a lump sum calculator. You only need a handful of details regarding your current loan and the size of the payment you’d like to make and the calculator will do the work for you. For more detailed advice regarding your mortgage compare and talk to the available mortgage brokers in your area.

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2 Responses to Lump Sum Repayment Calculator

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    gareth | July 8, 2013

    hi, we are about to receive a 100k lump sum we have two home loans on the one property 213k at 5.45% and 129k at 5.69% also a 7k personnel loan at 16.4%. into which loan(s) should we place the money

      Shirley | July 9, 2013

      Hi Gareth,

      Thanks for your comment.

      Since is a comparison website we’re not licensed to give any personalised financial advice. You may want to consider speaking to a financial advisor.


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