# How to use the ISLOGICAL function

**What is the ISLOGICAL function?**

The ISLOGICAL function returns TRUE if value is boolean.

**What is a Boolean value?**

A Boolean value in Excel is a value that can only be TRUE or FALSE. It represents binary logic and is the result of a logical expression using logical operators or a result of a few Excel functions that I'll discuss below.

Mastering Boolean logic and logical expressions is key to manipulating data and controlling workflow in Excel.

**What is binary logic?**

Binary logic refers to values having one of two states, TRUE or FALSE. This allows Boolean algebra in Excel using logical operators.

**What is a logical expression?**

A logical expression is a statement that evaluates to TRUE or FALSE. For example:

=A1<4

These expressions use comparison operators to evaluate a condition and produce a Boolean result.

**What are the comparison operators?**

= - equal sign

< - less than sign

> - greater than sign

These operators let you build more operators like this:

<> - not equal to

<= - less than or equal to

>= - greater than or equal to

These comparison operators let you create logical expressions like: A2<>5 meaning if the value in cell A2 is not equal to 5, the result is either TRUE or FALSE.

**What are the logical operators?**

The main logical operators in Excel are:

- AND - Returns TRUE if all conditions are true
- OR - Returns TRUE if any condition is true
- NOT - Negates a logical expression
- XOR - Returns TRUE if only one condition is true

**Other IS functions**

Excel Function | Description |
---|---|

ISBLANK(value) | Returns TRUE if the value is empty, FALSE otherwise |

ISERR(value) | Returns TRUE if the value is any error value except #N/A, FALSE otherwise |

ISERROR(value) | Returns TRUE if the value is any error value, FALSE otherwise |

ISEVEN(value) | Returns TRUE if the value is an even number, FALSE for odd numbers |

ISFORMULA(reference) | Returns TRUE if the cell contains a formula, FALSE otherwise |

ISLOGICAL(value) | Returns TRUE if the value is a logical value (TRUE/FALSE), FALSE otherwise |

ISNA(value) | Returns TRUE if the value is the #N/A error, FALSE otherwise |

ISNONTEXT(value) | Returns TRUE if the value is not text, FALSE if it is text |

ISNUMBER(value) | Returns TRUE if the value is a number, FALSE otherwise |

ISODD(value) | Returns TRUE if the value is an odd number, FALSE for even numbers |

### ISLOGICAL function Syntax

ISLOGICAL(*value*)

### ISLOGICAL function Arguments

value |
Required. The value you want to check for a boolean value. |

**What is a cell reference?**

A cell reference lets you "fetch" and use values in other cells in a formula.

There are two types of cell references:

- A1-style reference
- R1C1 reference

The A1-style reference is the default style in Excel, it names columns by letters from A to Z. After Z it starts over with AA, AB, and so on until XFD. Rows are numbered from 1 to 1048576, older Excel versions use less row numbers.

The R1C1-style uses row number and column number like: R1C1, R2C5 and R10C15. Rows are labeled R1, R2, R3 and so on, columns are labeled C1, C2, C3 etc.

The A1-style reference notation is the most common one, here are some examples:

A1 - single cell reference on the same worksheet

A1:D5 - reference to a cell range on the same worksheet

Budget!Z3 - a single cell reference to worksheet Budget

'Budget 2050'!A3 - a single cell reference to a worksheet containing a space character

There are two types of cell references:

- Relative cell references
- Absolute cell references

The examples above are all relative cell references, they change accordingly if a cell is copied and pasted to another cell which absolute cell references do not.

The $ dollar character lets you an absolute cell reference meaning you can lock a cell reference horizontally, vertically or both. Here is one example:

A$1 has a relative column reference but an absolute row reference, this means that the column letter may change if the cell is copied and pasted to cells in another column than A.

### ISLOGICAL function example

Formula in cell C3:

Note that Excel interprets a number not equalÂ to 0 (zero) as TRUE and 0 (zero) as FALSE, for example, in a IF function. However, the ISLOGICAL function does not.

The ISLOGICAL function is very useful to identify error values in arrays. Most Excel functions return the same error value, however, this function returns FALSE if it encounters an error.

### Functions in 'Information' category

The ISLOGICAL function function is one of 19 functions in the 'Information' category.

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