The Excel ISLOGICAL function returns TRUE when a cell contains the logical values TRUE or FALSE, and returns FALSE for cells that contain any other value, including empty cells.

Test if a value is logical

A logical value (TRUE or FALSE)

=ISLOGICAL (value)

**value**- The value to test as logical.

Use the ISLOGICAL function to check if a value is logical. ISLOGICAL will return TRUE when a value is TRUE or FALSE.

For example, =ISERROR(A1) will return TRUE if A1 contains either TRUE or FALSE.

Note that 1 and 0 (zero) are not evaluated as TRUE and FALSE. However, you can use the AND function to evaluate 1 and 0 and TRUE and FALSE.

Normally, **value** is supplied as a cell address.

ISLOGICAL is part of a group of functions called the IS functions, which are often used to test the result of formulas for errors.