IS functions
This article describes the formula syntax and usage of the IS functions in Microsoft Office Excel.
Description
Each of these functions, referred to collectively as the IS functions, checks the specified value and returns TRUE or FALSE depending on the outcome. For example, the ISBLANK function returns the logical value TRUE if the value argument is a reference to an empty cell; otherwise it returns FALSE.
You can use an IS function to get information about a value before performing a calculation or other action with it. For example, you can use the ISERROR function in conjunction with the IF function to perform a different action if an error occurs:
=IF(ISERROR(A1), "An error occurred.", A1 * 2)
This formula checks to see if an error condition exists in A1. If so, the IF function returns the message "An error occurred." If no error exists, the IF function performs the calculation A1*2.
Syntax
ISBLANK(value)
ISERR(value)
ISERROR(value)
ISLOGICAL(value)
ISNA(value)
ISNONTEXT(value)
ISNUMBER(value)
ISREF(value)
ISTEXT(value)
The IS function syntax has the following argument:

value Required. The value that you want tested. The value argument can be a blank (empty cell), error, logical value, text, number, or reference value, or a name referring to any of these.
Function 
Returns TRUE if 
ISBLANK 
Value refers to an empty cell. 
ISERR 
Value refers to any error value except #N/A. 
ISERROR 
Value refers to any error value (#N/A, #VALUE!, #REF!, #DIV/0!, #NUM!, #NAME?, or #NULL!). 
ISLOGICAL 
Value refers to a logical value. 
ISNA 
Value refers to the #N/A (value not available) error value. 
ISNONTEXT 
Value refers to any item that is not text. (Note that this function returns TRUE if the value refers to a blank cell.) 
ISNUMBER 
Value refers to a number. 
ISREF 
Value refers to a reference. 
ISTEXT 
Value refers to text. 
Remarks

The value arguments of the IS functions are not converted. Any numeric values that are enclosed in double quotation marks are treated as text. For example, in most other functions where a number is required, the text value "19" is converted to the number 19. However, in the formula ISNUMBER("19"), "19" is not converted from a text value to a number value, and the ISNUMBER function returns FALSE.

The IS functions are useful in formulas for testing the outcome of a calculation. When combined with the IF function, these functions provide a method for locating errors in formulas (see the following examples).
Example 1
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?

Select the example in this article.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In Excel, create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.


Example 2
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?

Select the example in this article.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In Excel, create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

