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A to Z of Excel Functions: the ISLOGICAL Function

31 May 2021

Welcome back to our regular A to Z of Excel Functions blog.  Today we look at the ISLOGICAL function.

 

The ISLOGICAL function

At the time of writing, there are 12 IS functions, i.e. functions that give rise to a TRUE or FALSE value depending upon whether a certain condition is met:

  1. ISBLANK(reference): checks whether the reference is to an empty cell
  2. ISERR(value): checks whether the value is an error (e.g. #REF!, #DIV/0!, #NULL!).  This check specifically excludes #N/A
  3. ISERROR(value): checks whether the value is an error (e.g. #REF!, #DIV/0!, #NULL!).  This is probably the most commonly used of these functions in financial modelling
  4. ISEVEN(number): checks to see if the number is even
  5. ISFORMULA(reference): checks to see whether the reference is to a cell containing a formula
  6. ISLOGICAL(value): checks to see whether the value is a logical (TRUE or FALSE) value
  7. ISNA(value): checks to see whether the value is #N/A.  This gives us the rather crude identity ISERR + ISNA = ISERROR
  8. ISNONTEXT(value):  checks whether the value is not text (N.B. blank cells are not text)
  9. ISNUMBER(value): checks whether the value is a number
  10. ISODD(number): checks to see if the number is odd.  Personally, I find the number 46 very odd, but Excel doesn’t
  11. ISREF(value): checks whether the value is a reference
  12. ISTEXT(value): checks whether the value is text.

As stated above, the ISLOGICAL function checks whether the value is logical (i.e. TRUE or FALSE).  It has the following syntax:

ISLOGICAL(value)


The ISLOGICAL function has the following argument:

  • value: this is required and represents the value for which you wish to determine whether it contains a logical (TRUE or FALSE) reference. 

It should be further noted that:

  • if value refers to more than one cell, the formula the result will be FALSE
  • if value is not a valid data type, such as a defined name that is not a reference, ISLOGICAL returns the #VALUE! error value.

Please see my example below: 

We’ll continue our A to Z of Excel Functions soon.  Keep checking back – there’s a new blog post every business day.

A full page of the function articles can be found here

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