A compound interest widget


Compoundeeyo is an OSX Dashboard Widget that calculates compound interest from a savings and investment perspective. Compoundeeyo helps you detemine how much an initial investment will be worth in a specified amount of time. It is very flexible in that it allows for different investment lifetimes, different compounding periods, periodic withdrawals or deposits, and different rates of return. In addition to determining the total accumulated amount of your investment, the Compoundeeyo widget also provides an inflation adjusted amount. It also itemizes the interest earned vs. the total amounts deposited. For a complete description of the widget, please see the documentation section below. You can also look at the screenshot.

Download (Version 0.19)

Version History

0.19 (Latest)

  • Fixed problem where decimals not allowed in duration
  • Fixed issue where long investment periods were too slow by using
  • Fix performance problem if large number of months was specified for duration
  • Added check-for-updates support
  • Version in UI is now set from program variable
  • Enabled Makefile to deploy widget without Dashcode
  • Added Version History section to web-page and automated its creation
Full list of changes


Mac OS X 10.4.3 or later is required.

Install on Leopard (10.5.x)

If the above file does not open automatically after downloading, then open it. It will open your Dashboard with the Compoundeeyo widget selected. Choose Keep to add Compoundeeyo to your Dashboard.

Install on Tiger (10.4.x)

If you're using Safari, click the download link. When the widget download is complete, Show Dashboard, click the Plus sign to display the Widget Bar and click the widget's icon in the Widget Bar to open it. If you're using a browser other than Safari, click the download link. When the widget download is complete, unarchive it and place it in /Library/Widgets/ in your home folder. Show Dashboard, click the Plus sign to display the Widget Bar and click the widget's icon in the Widget Bar to open it.

Support & Feedback

Please send all support requests or any other feedback to We are interested in hearing from anyone who finds this tool useful.

User Documentation

Input Fields

The following fields are inputs to the compound interest calculation. All of the numeric inputs can be specified as formatted numbers that include commas and dollar signs to allow for easier input of larger numbers.
  • Principal - The amount of the initial investment.

  • Rate - The annual interest rate the investment will earn.

  • Compound - How frequently the interest will be compounded. This can be daily, months, quarterly, semi-annually, or annually

  • Duration - The length of time the investment will last. This can be specified in days, months, or years.

  • Deposits - The amount of money that will be periodically deposited into the account. If money is to be periodically withdrawn instead, use a negative number here. You can specify how often these deposits or withdrawals occur by using the pull-down menu to the right of the input field. Allowable deposit periods are daily, monthly, quarterly, semi-annually, and anually.


By clicking the i in the lower right corner of the widget, you can flip the widget over to see the preferences. There are 2 preferences which play a roll in the compound interest calculation. The description of these prefereces follows.


  • Inflation Rate - This is the constant average anual rate that is to be used for calculating the inflation adjusted total. It is defaulted to 3.2%, but you can set it to any value in order to test how different inflation rates will affect your savings.

  • Deposits Made At - This preference allows you to specify whether the periodic deposits are made at the beginning of the deposit period or the end of the period. This is important when determining how the deposits should be added to the total and what portion of them should be compounded.

  • Check for Updates - If this is checked, the widget will automatically check for updates. If an update is available, a link will appear that can be clicked on to download the new version. Follow the installation instructions above to install the new version along with an additional step of confirming the replacement of the older version of the widget.


After the Calculate button is clicked, results will be calculated and displayed in the fields on the bottom portion of the widget. The meanings of these various results are described below.
  • Amount - The total accumulated amount of the investment including all of the deposits and compounded interest, as calculated using the specified inputs and preferences.

  • Inflation Adjusted - The amount as specified above, but also adjusted for inflations using the annual inflation rate specified in the preferences on the back of the widget.

  • Interest - The total interest earned over the lifetime of the investment. This is the interest portion of the total accumulated amount.

  • Additions - The total amount deposited earned over the lifetime of the investment. This is the total of all of the periodic deposits as per the parameters specified.

  • Dates -These are the beginning and ending dates that the compound interest calculation is run over.

Known Issues, Bugs and Caveats

  • Day counting standards are not used. Compounding daily will lead to slightly different results than some other calculators

  • The widget uses the first day of current year as the starting time. It would be better if tomorrow, the next business day, or an input field were used.

  • Compoundeeyo uses an iterative method for it's calculations. For investment periods of longer than 100 years, 'time value of money' formulas are used for performance reasons.

  • There inflation adjusted amount when using the the formulas is incorrect when the deposit frequency is less often than the compounding frequency. This is still being investigated. Until it is fixed, the formulas will only be used for the rare 100 year and longer calculations.

More Documentation

Other Savings Calculators


Compoundeeyo is made available in the hopes that it may be useful. It is provided "AS IS" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Compoundeeyo is made available as a self-help tool for informational and educational purposes only. It does not constitute investment advice. The results are approximations. Do not make financial decisions based on the results from this widget.