XL: How to Calculate Compound Interest

For a Microsoft Excel 98 version of this article, see 191017 .


Compound interest is the amount that a dollar invested now will be worth in a given number of periods at a given compounded interest rate per period.

Although Microsoft Excel does not include a function for determining compound interest, you can use the following formula for this calculation
where PV is present value, R is the interest rate, and N is the number of investment periods.

More Information

Suppose you have $1,000.00 in an investment account. The account pays 8 percent interest and this interest is compounded annually. How much will the investment be worth at the end of three years? There are two ways to find the amount:
  • Use a Fixed Formula
  • Create a Function Macro to Determine Compound Interest

Use a Fixed Formula

The following formula typed into a cell on a worksheet, returns the correct value of $1,259.71:
However, all of the information is 'hard-coded' into the formula and you must manually change the formula any time the figures change.

Create a Function Macro to Determine Compound Interest

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A custom function is more flexible because none of the actual raw data is 'hard-coded' into the function; the user just types the data for the calculation instead of the actual calculation. To create this custom function, follow these steps:

  1. Start Microsoft Excel.
  2. Press ALT+F11 to start the Visual Basic Editor.
  3. On the Insert menu, click Module.
  4. Type the following code in the new module:
    Function Yearly_Rate(PV As Double, R As Double, N As Double) As Double

    Yearly_Rate = PV*(1+R)^N 'Performs computation

    End Function
To use the custom function, follow these steps:

  1. Type the following values in your worksheet:

    Cell Value
    A1 1000.00
    A2 .08
    A3 3.00
    These values represent the following:

    • A1: Present value of the investment
    • A2: Interest rate
    • A3: Number of investment periods
  2. In any blank cell, type the following formula
    where A1, A2, and A3 are the cells that contain the present value, interest rate, and number of investment periods respectively.
The cell in which you typed the formula displays $1,259.71. This is the amount your original investment of $1000.00 is worth after three investment periods at 8 percent compound interest.


"Cost Accounting-A Managerial Approach," Charles T. Horgren, Prentice- Hall,Inc., Fourth Edition, pages 906-907