In Microsoft Excel, the ISLOGICAL function is generally used to check whether a given argument contains a boolean value (**TRUE** or **FALSE**) or not. In this article, you’ll get to learn how you can use this ISLOGICAL function efficiently in Excel with appropriate illustrations.

The above screenshot is an overview of the article, representing a few applications of the **ISLOGICAL** function in Excel. You’ll learn more about the methods along with the other functions to use the **ISLOGICAL** function with ease in the following sections of this article.

**Table of Contents**hide

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**Introduction to the ISLOGICAL Function**

**Function Objective:**

**The ISLOGICAL function is used to check if a cell contains any boolean or logical values (TRUE or FALSE) or not.**

**Syntax:**

**=ISLOGICAL(value)**

**Argument Explanation:**

Argument | Required/Optional | Explanation |
---|---|---|

value |
Required |
Any value or a cell reference or a range of cells. |

**Return Parameter:**

**A boolean value: TRUE if the function finds a logical value (TRUE or FALSE) in its argument or cell reference, otherwise returns FALSE.**

**4 Suitable Examples of Using ISLOGICAL Function in Excel**

**1. Basic Use of ISLOGICAL Function in Excel**

In the picture below, a number of data is lying in **Column B**. We’ll find out which values are logical or boolean ones by applying the **ISLOGICAL** function in **Column D**.

For example, the first output in **Cell D5** comes with the following formula:

`=ISLOGICAL(TRUE)`

And the function returns **TRUE** which means **TRUE** in **Cell B5** is a logical function. If it was not a logical function then the function would return **FALSE** as shown for the second value in **Cell B6**.

Please don’t forget to use **Double-Quotes(“ “)** while inputting text data as the argument. For a boolean or a numeric value, you don’t need to use **Double-Quotes**.

**2. Use of ISLOGICAL Function with Cell Reference in Excel**

**ISLOGICAL **function accepts a cell reference too. We’ll now determine the outputs for all the data shown in the previous section by referring to their cell references.

In the output **Cell D5**, the required formula will be:

`=ISLOGICAL(B5)`

After pressing **Enter** and auto-filling the rest of the cells in **Column D** with **Fill Handle**, you’ll get a similar output as found in the previous example.

**3. Combining IF and ISLOGICAL Functions in Excel**

We can incorporate **IF **and** ISLOGICAL** functions together to display defined messages. For the values in **Column B**, the combined formula will return **‘Logical’** for a boolean value and **‘Not Logical’** for a non-boolean value.

For example, the output in **Cell D5** will be:

`=IF(ISLOGICAL(B5),"Logical", "Not Logical")`

And the formula will return **‘Logical’** as **TRUE** is a proper logical or boolean value. Similarly, you can extract the resultant values for all other inputs with their relative cell references.

**4. ISLOGICAL Function with Data Validation in Excel**

In this section, we’ll see how data validation works with the **ISLOGICAL** function. In the screenshot below, we have to input **TRUE or FALSE** based on the statements in **Column B**. If you type any other text or value then an error message will be displayed.

**📌**** Step 1:**

➤ Under the **Data** ribbon, select the **Data Validation** command from the Data Tools drop-down.

A dialogue box named **‘Data Validation’** will open up.

**📌**** Step 2:**

➤ Select the **Custom** option from the **Allow** list for **Validation Criteria.**

➤ In the formula box, type:

`=ISLOGICAL(C5)`

➤ Go to the **Input Message** tab.

**📌**** Step 3:**

➤ Type** “Input Data”** for Title.

➤ For the** Input** message, insert the following text or similar instruction you prefer:

**“Type TRUE or FALSE”**

➤ Open **Error Alert** tab.

**📌**** Step 4:**

➤ In the title box, type **‘Error!’**

➤ Insert the following text as the **Error** message:

**“Type a boolean value- TRUE or FALSE only.”**

➤ Press **OK**.

Now tap on your output cell and you’ll be shown an input message.

**📌**** Step 5:**

➤ Type a text, such as **“It’s True”** in **Cell C5** for the statement present in **Cell B5**. An error message will be displayed with the defined texts.

➤ Press **Cancel** and the message box will disappear.

**📌**** Step 6:**

➤ Now input **TRUE** only in the output **Cell C5** and this time no error message will come up.

**💡**** Things to Keep in Mind**

🔺 ISLOGICAL function is a member of **IS** group of functions. They are critical in the development of dashboard interfaces and are heavily used with the **IF** function.

🔺 To input text data you have to use **Double-Quotes(“ “)** around the argument of the ISLOGICAL function.

🔺 ISLOGICAL function doesn’t return any error no matter what you input as the argument. If it doesn’t recognize a boolean value, it’ll always return **FALSE**.

**Concluding Words**

I hope all of the suitable methods mentioned above to use the** ISLOGICAL **function will now inspire you to apply them in your Excel spreadsheets with more productivity. If you have any questions or feedback, please let me know in the comment section. Or you can check out our other articles related to Excel functions on this website.

**Further Readings**

- How to Use ISTEXT Function in Excel (3 Examples)
- How to use ISNA function in Excel (4 Examples)
- How to Use ISEVEN Function in Excel (2 Examples)
- How to Use ISODD Function in Excel (With 4 Examples)
- How to Use ISNUMBER Function in Excel (7 Examples)
- How to Use ISBLANK Function in Excel (2 Examples)
- How to Use ISERROR Function in Excel (With 5 Examples)