FREE Interactive Mortgage Bond Calculator

BondBuster is a Java desktop application. It allows you to monitor your mortgage bond in terms of balance outstanding, monthly payments, and interest paid per month or per day.

Importantly it illustrates the substantial effect interest has on the total amount repaid.

  For example, on a 20 year mortgage you can easily be paying back double the purchase price of the house!


  • Bond details, payments, and interest rates are stored in simple xml files, allowing for easy updating with your favourite editor (eg. Notepad for Windows or gedit for Linux). These files are located in the data sub-folder.
  • Interest rate can be either fixed or variable (relative to prime). Interest is amortised daily based on the rate effective on each day
  • Scenario planning: You can change the values and hit Calculate to see the effects. In particular you can make "ad-hoc" payments and see how dramatically these can reduce the debt and lifetime of the bond.

    So instead of that expensive holiday or new Harley, Stick it in the Bond and Save Big!

  • A bar chart that illustrates the portion of your annual payments allocated to interest versus capital.


Download sites


Installation instructions:

Note: You must have Java (JRE 1.7 or later) installed on your PC to run this application.

Windows Linux

- Download the and save to your PC
- In your Downloads folder Right click on the icon and "Extract all" the contents to a new folder, e.g.
My Documents\BondBuster
- Navigate to that folder and double-click on the run icon

- Download the and save to your PC
- In your Downloads folder (eg. Desktop) open the package and extract to a new folder
- Navigate to that folder and find the file Right click Properties, select Permissions and tick Executable. Then right click and select Run or "Run in Terminal".
If that doesn't work you may need to run from the command line in a terminal window, e.g.
cd ~/BondBuster
./ &

If you can't download, install or run the application, or if you have any comments please Contact here