Compoundee User Guide


Quick Tips

  • Tap Return or swipe down on the results to dismiss the keyboard.
  • Swipe from right-to-left to view amortization.
  • Use the Compose button at the top right to email results.
  • Use the Recents button alongside the text fields for recent entries.
  • For Withdrawals, enter a negative number into the Deposits field.

Choosing the variable

After launch, and at the bottom of the screen are 5 buttons that allow you to select the variable that you would like to solve. Tapping on one of these controls will alter the rest of the display such that the appropriate input fields are available that correspond to the chosen calculation. Also updated is the results window so that the appropriate results are displayed. The available variables to solve for are:

  • Total(fv) - Tapping on this will allow you to solve for the total accumulation of your investment. This value is displayed in the results window along with some other interesting numbers. These include the amount after taxes and expenses along with what happens after inflation is applied to the after tax and expense value. This last value is what the total is in today's dollars. This number provides meaning to the larger number, because it more accurately reflects how much you will be able to purchase with the total at the end of your investment. Also shown when solving for Total(fv) are the total interest earned and the total contributions. Finally, at the top left corner of the Results Window is an Information button. Tapping that button will provide further details about the calculation.
  • Rate - Tapping on this tab will allow you to calculate the necessary average annual rate of return for your investment in order to achieve your goals as set according to the input fields. The default rate type is a nominal APR. Below this result is an amount a rate that takes taxes and expenses int account, along with appear a tax and inflation adjusted rate. This is the nominal APR that would be needed to accumulate the desired Total after tax and inflation effects are accounted for. You can choose to solve for a different type of rate by tapping on the rate type button at the bottom right of the results window. This will present a menu that allows you to solve for a periodic rate or an APY.
  • Duration - Tapping on this tab will allow you to solve for the necessary lifetime of the investment in order to achieve your goals as set according to the input fields. The tax and inflation adjusted results shows the duration necessary to achieve those goals if the effects of taxes and inflation are counted. To change the units the duration is displayed in, tap on the Duration Unit button below the results.
  • Deposits - Tapping on this tab will allow you to solve for the amount of periodic deposits you will need in order to achieve your investment goals. The tax & inflation adjusted results shows the amount of periodic deposits necessary if the effects of taxes and inflation are counted. To solve for a different deposit frequency, tap on the Frequency button displayed below the result.
  • Principal - Tapping this control will solve for the initial investment you will need to make in order to achieve your goals as set by the other input fields. The tax & inflation adjusted results shows the amount of initial investment necessary if the effects of taxes and inflation are counted.

Basic Input Fields

The following fields are used as inputs to the calculator. The specific input that are displayed are dependent on the variable to be solved, as described above. It should be noted that all of the numeric inputs can include commas and currency symbols to allow for easier reading of larger numbers. Including these separators or the percent symbols is not required, however.

The other attempt to make input easier is a history facility for each field. Tapping on this will bring up a menu of the past several entries for that field.

This list of input fields follows:

  • Principal - The amount of the initial investment.
  • Total - The future value of the investment. This is the total accumulation of the investment at the end of the specified duration.
  • Rate - The interest rate the investment will earn. The default rate type is a simple annual interest rate (a nominal APR). You can change the rate type to a periodic rate or and APY by tapping the Rate Type button on the right.
  • Duration - The length of time the investment will last. This can be specified in days, weeks,months, quarters, or years. To change units, tap on the Duration Unit button to the right, after entering the numeric portion of the duration into the textfield.
    Whe the actual/actual day counter is used, this row will be replaced by two buttons that allow you to choose the beginning and ending date of the investmenr. replaced by a label showing the beginning and ending date of the investment. Tap on this row to change these dates.
  • 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. You can specify how often these deposits or withdrawals occur using the button to the right of this text field.
    Tapping on the button to the right of the deposits field allows you to change the frequency of the deposits. Deposits can be made on a daily,monthly,quarterly,semi-annual, or yearly basis.
  • Compounding Frequency - Tap this to change how interest will be compounded. This can be daily, months, quarterly, semi-annually, or annually. Tap the desired choice on the subsequent menu to choose.

Advanced Input Fields

  • 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.
  • Tax Rate - This is the average annual combined tax rate you expect to pay on these earnings.
  • Expense Rate - This is the rate of expenses as compared with total value of the investment. It is usually meant to be used for the expense ratio of a mutual fund.
  • Deposit Time - This specifies whether the periodic & deposits will be made at the beginning of the period or at the end of the deposit period.
  • Exra Deposits - This allows for extra annual deposits to be included in the calculation. This can be useful to account for savings of christmas bonuses and other types of annual savings in addition to the periodic deposits.


The results are automatically updated whenever the input parameters change. Sometimes, the results are hidden by the keyboard while input is enterred into the text fields. To dismiss the keyboard, hit the return key on the on-screen keyboard. Alternatively you can dismiss the keyboard by tapping almost anywhere on the screen outside of the text input field.

Add bookmark

You can save all of the input parameters by tapping the Action button at the top left corner of the screen and choosing 'Add bookmark'. This will bring you to a screen where you can enter a name and description for the current set of inputs. Once saved, you can quickly restore this set of inputs using the Bookmarks screen described further down.


You can navigate to the amortization section either by swiping from right to left or by tapping the Action button at the top left corner of the screen and choosing 'Amortization'.

The amortization section shows the investment growth broken down by the smaller of the compounding frequency and the duration units. Each row in this table shows a period, the interest earned during that period, the cumulative interest, and the total accrual at that time of the investment. This table always shows these numbers and does not change with the variable being solved.

Emailing the Results

You can save various calculations by emailing them. Tap the Compose button at the top right of the screen to bring up a mail composer pre-filled in with the inputs and results of the calculation. Select a recipient, and click send at the top right of the mail window to send the email.

Clear Inputs

To reset all of the numeric inputs to 0, tap the Action button at the top left of the screen. Then confirm by tapping the 'Clear Inputs' button that appears.


The button second from the left at the top of the screen is the Bookmarks button. Tapping that button will bring up a screen that displays the previously saved bookmarks. Subsequently tapping on the name or description of one of those bookmarks will load the input parameters previously stored for the tapped bookmark. The bookmarks screen will be dismissed once a bookmark is selected. To the right of each bookmark on the bookmarks screen is a blue detail disclosure indicator button. Tapping on that button will bring up a screen that allows you to edit the name and/or description of the bookmark to the left.

At the top right of the Bookmarks screen is an Edit button. Tapping that button will place the screen into edit mode. To the left of each bookmark there will be a red button. Tapping on that button will display another button that allows you to delete the bookmark. To the right of each book mark while in edit mode is a control that allows you to reorder the bookmarks. Tap on that control and drag the bookmark to the desired position. Tap the Done button at the top right to confirm the new bookmark positions once they are all in the dessired order.

Known Issues, Bugs and Caveats

  • Compoundee sometimes attempts to give a reasonable answer even in the face of impossible parameters. This can occasionally result in approximated results for rate-of-return or durations. Often, the result for an impossible equation will be 'N/A'. A better way to handle all of this would probably be to validate input and alert users of the problem immediately.
  • Compoundee offfers the use of the 30/360 day counting standard or the Actual/Actual (AFB) day counting standard. This can cause some differences can occur when comparing results to other calculators that use different day counting standards. This would most often occuring when using daily and weekly frequencies and durations. To learn more about various day-counting conventions and the conventions that are used for different investment types, please visit: Day count convention at WikiPedia.
  • When the duration does not divide evenly by the deposit period, deposits are pro-rated according to the fractional duration. In other words, if deposits are being made monthly and the duration is 45 days, the deposits will be included one and half times. This behavior is only true for the main results screen. The amortization calculation uses an interative calculation that properly distributes deposits most of the time. The exception to this is when Actual/Actual daycounting method is used.
  • The main results can differ from the amortization results. This is due to the fact that the main result use a formulaic calculation and the amortization results use an iterative method.
  • The details screen when accessed through the main screen does not accurately represent the taxes & expenses associated with the calculation. Instead, it shows the effect of those fees on the result. In other words, it includes the lost interest as a result of those expenses. When the details screen is accessed through the amortization screen, it will correctly show the interest, expenses, & taxes.
  • Email results will only show a maximum of 500 amortization periods
  • There is no capability to increase the deposits to account for inflation.
  • The tax rate is overly simplistic in that it is a combined federal and local tax rate. These should be separated so that the local taxes can be deducted from the amount the federal tax is calculated on.


Compoundee 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. Compoundee not constitute investment advice. The results are approximations. Do not make financial decisions based on the results from this calculator. Please consult with a ceritifed financial planner for investment advice.