Understanding Functions

You already know that Excel allows you to create formulas in the cells that make up your worksheets. To make your formulas even more powerful, Excel provides well over 200 functions you can use. These functions facilitate everything from simple summation to complex financial and mathematical models. The basic functions can loosely be divided into categories such as database, date and time, financial, information, logical, lookup and reference, math and trig, statistical, and text. When you use add-ins with Excel, the number of available functions can increase even more.

As an example of how functions are used, suppose you need a formula that returns the sum of the cells in C7 through C19. Rather than put together a formula that uses the plus sign for each of the cells in the range, you can use the following formula:

=SUM(C7:C19)

The name of the function used here is SUM, and it uses the arguments indicated between the parentheses. In this case, the cell range C7 through C19 serve as the argument for the function. (The colon between the cell references indicates a range. It tells Excel that it should include everything between the two cells.)

While SUM is a rather simple function, Excel includes many others that provide a multitude of capabilities. For instance, suppose you want to determine how much money you would have in the bank after 20 years if you participated in a semi-monthly payroll deduction program. If the program paid a fixed interest rate of 5.75% and you had $125 deducted every pay period, you could use the following formula:

=FV(5.75%/24,20*24,-125)

The result of the function in this formula is $112,374.89. If you wanted to play "what-if" scenarios, you could set up the formula to use cell references. Because the formula relies on the values in the cells referenced, any changes to the basic values in those cells results in an automatically recomputed future value.