Microsoft Office

Part IV
Using Advanced Excel Features
Formulas returning an error
A formula may return any of the following error values:
n #DIV/0!
n #N/A
n #NAME?
n #NULL!
n #NUM!
n #REF!
n #VALUE!
The following sections summarize possible problems that may cause these errors.
TIP
Excel allows you to choose how error values are printed. To access this feature, display the
Page Setup dialog box and click the Sheet tab. You can choose to print error values as displayed
(the default), or as blank cells, dashes, or #N/A. To display the Page Setup dialog box, click the dialog
box launcher on the Page Layout ➪ Page Setup group.
#DIV/0! errors
Division by zero is not a valid operation. If you create a formula that attempts to divide by zero, Excel displays
its familiar #DIV/0! error value.
Because Excel considers a blank cell to be zero, you also get this error if your formula divides by a missing
value. This problem is common when you create formulas for data that you haven’t entered yet, as shown in
Figure 32.1. The formula in cell D2, which was copied to the cells below it, is
=(C2-B2)/C2
This formula calculates the percent change between the values in columns B and C. Data isn’t available for
months beyond May, so the formula returns a #DIV/0! error.
To avoid the error display, you can use an IF function to check for a blank cell in column C:
= IF(C2=0,””,(C2-B2)/C2)
This formula displays an empty string if cell C2 is blank or contains 0; otherwise, it displays the calculated
value.
Another approach is to use an IFERROR function to check for any error condition. The following formula,
for example, displays an empty string if the formula results in any type of error.
=IFERROR((C2-B2)/C2,””)
Tracing Error Values
O
ften, an error in one cell is the result of an error in a precedent cell. For help in identifying the cell that
is causing an error value to appear, activate the cell that contains the error and then use Formulas ➪
Formula Auditing ➪ Error Checking ➪ Trace Error. Excel draws arrows to indicate which cell is the source of
the error. When you’ve identified the error, use Formulas ➪ Formula Auditing ➪ Error Checking ➪ Remove
Errors to get rid of the arrow display.
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