The ISNUMBER function in Google Sheets **is used to determine if a value is a number.**

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This function is useful because it helps you see if a value in a certain cell contains a number. This is especially helpful when you are trying to catch an entry that is not formatted to the style of a number. Remember that some text that looks like numbers or even a date can actually be formatted differently. This will lead to some broken formulas and mismatched information in your spreadsheets at the end of the day, and you will run into some difficulties with your overall data in the long run.

Let’s look at an example.

You have a spreadsheet that details the information on your students. They are expected to check their quizzes amongst themselves and submit their individual scores in an online system or platform. Perhaps their entries are not formatted correctly, but some values are not available to be read and used in different calculations.

**How should we go about this problem?**

The `ISNUMBER`

function takes in the text input to determine if it contains a number or not. Instead of scanning the entire document, using this function can be helpful.

## The Anatomy of ISNUMBER Function in Google Sheets

The syntax of the `ISNUMBER`

function is as follows:

=ISNUMBER(value)

Let’s have a look at each part of the function to understand what is going on here:

`=`

is the equals sign that starts off any function in Google Sheets.`ISNUMBER`

is the name of our function.`value`

is the value to be verified as a number.

Note that this function is typically used with conditional formatting rules, which we will illustrate in the example below.

Also, when you type something in the formula with quotation marks, then the data inside those question marks is considered a string, much like a word as a set of letters. For example, the function will return `FALSE`

if you try to type in **=ISNUMBER(“101”)**, where 101 will be considered a string.

## A Real Example of Using ISNUMBER Function

Let’s look at the example below to see how to use the `ISNUMBER`

function in Google Sheets.

#### Determining Number Validity in Google Sheets

This is a simple problem. We want to know if a value is a valid number or not.

The function takes just one argument. So in the equation, it will look like:

=ISNUMBER(D3)

As a result, we get **TRUE**.

This simple problem can be practiced to perfection. Use the link below to get a copy of this problem set:

## How to Use ISNUMBER Function in Google Sheets

In this section, we will show you a step-by-step process on how to use the `ISNUMBER`

function in Google Sheets.

In this problem, we will look through the values in a spreadsheet column. To make the search easier, will use the function alongside Conditional Formatting.

#### Determining Number Validity in Google Sheets with Conditional Formatting

- To begin, prepare your spreadsheet with the websites you want to check.

- Highlight the cells that you want to know are numbers or not.

- From the Menu Bar, choose Format. Scroll to the bottom of the list and choose “
**Conditional formatting.**“

- This will open in the Conditional Formatting menu.

- It’s time to create a Format rule. From the dropdown list under “
**Format cells if…**” scroll all the way to the bottom and choose “**Custom formula is**“

- Next, we will use the
`ISNUMBER`

function to highlight the correct cells. Insert`=ISNUMBER(C3)`

, with Cell**C3**being the first cell in the list.

- Click done, and you will see the new conditional format rule that you created.

- Now, you can see which items are numbers. That’s it – you are now done!

The `ISNUMBER`

function can help tidy up your spreadsheet and point out any missing information or mistakes. This should definitely help you avoid mistakes in your spreadsheets in the future, too.

And there you have it – you can now use the `ISNUMBER`

function in Google Sheets together with the **other numerous Google Sheets formulas** to create even more effective formulas.