IS Functions

Description: This section describes the eight functions used for testing the type of a value or reference.

ISBLANK
ISERR
ISERROR
ISLOGICAL
ISNONTEXT
ISNUMBER
ISREF
ISTEXT

Each of these functions, referred to collectively as the IS functions, checks the type of value and returns TRUE or FALSE depending on the outcome. For example, the ISBLANK function returns the logical value TRUE if the tested value is a reference to an empty cell; otherwise it returns FALSE.

Syntax: ISxxxx(Value)

Value is the value you want tested. Value can be a blank (empty cell), error, logical, 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.
ISNONTEXT	Value refers to any item that is not text. (Note that this function returns TRUE if 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 to the IS functions are not converted. 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, 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, they provide a method for locating errors in formulas (see the following examples).

Example:

ISLOGICAL(TRUE) = TRUE
ISLOGICAL("TRUE") = FALSE
ISNUMBER(4) = TRUE

Suppose C1:C5 on a worksheet of gold prices in different regions shows the following text values, number values, and error values: "Gold", "Region1", #REF!, $330.92, #N/A, respectively.

ISBLANK(C1) = FALSE
ISERROR(C3) = TRUE
ISERR(C5) = FALSE
ISNUMBER(C4) = TRUE [if the $330.92 was entered as a number and not as text]
ISREF(Region1) = TRUE [if Region1 is defined as a range name]