This guide covers everything you need to know about the Google Sheets ISNUMBER function, including its definition, syntax, use cases, and how to use it.

## What is the ISNUMBER Function? How Does It Work?

The ISNUMBER function in Google Sheets returns a Boolean value, either TRUE or FALSE, after evaluating whether a particular value is a number. Its primary purpose is to verify and differentiate numeric values from text, references, errors, or blanks in the data set.

In operation, the ISNUMBER function evaluates a specified value. If this value is a number or a reference to a cell containing a numeric value, the function will return TRUE. In contrast, the function will return FALSE if the value under evaluation is text, a cell reference containing non-numeric data, an error, or a blank.

It’s important to note that the ISNUMBER function recognizes numerical data distinctly from numerical values within a text string. For example, if you apply ISNUMBER to a number enclosed in a string, such as ISNUMBER(“123”), the function will return FALSE despite “123” being a number because it considers the entire value as text.

## ISNUMBER Syntax

The syntax and arguments for the function are as follows:

**ISNUMBER(value)**

**value**: This is the value you want to verify as a number. It can be a number, a reference to a cell containing a numeric value, or a formula that results in a numeric value.

Here are some important notes regarding the syntax and arguments:

- The ISNUMBER function is case-insensitive. This means that it treats lowercase and uppercase characters as the same.
- If the value argument is an error value or a reference to a cell containing an error value, the ISNUMBER function will return FALSE.
- The ISNUMBER function does not consider logical values (TRUE and FALSE) as numeric values. Therefore, ISNUMBER(TRUE) and ISNUMBER(FALSE) will both return FALSE.

## Examples of How to Use the ISNUMBER Function

Here are some practical examples of how to use the ISNUMBER function in Google Sheets:

### Example #1: Basic Use of ISNUMBER

The most straightforward use of ISNUMBER is to determine if a cell contains a number. For instance, if you have the number 5 in cell A1, you can use the formula =ISNUMBER(A1). Google Sheets will return TRUE, indicating that cell A1 contains a number.

### Example #2: Using ISNUMBER with Text

ISNUMBER can also identify if a cell contains a number within a text string. For instance, if you have the text “123 Main Street” in cell B2, you can use the formula =ISNUMBER(B2). Google Sheets will return FALSE because even though the cell contains numbers, it is not recognized as a number because it is part of a text string.

### Example #3: Using ISNUMBER with Non-Numeric Characters

If a cell contains a number and non-numeric characters, ISNUMBER will return FALSE. For example, if you have “50%” in cell C3 and use the formula =ISNUMBER(C3), Google Sheets will return FALSE because “%” is not recognized as part of a number.

### Example #4: Using ISNUMBER in Combination with SEARCH Function

The ISNUMBER function is especially handy when used alongside other functions like SEARCH. To illustrate, if you want to find out whether the number 60 appears in the text “The car speed is 60 mph” located in cell D4, you can use the formula =ISNUMBER(SEARCH(“60”, D4)). If Google Sheets returns TRUE, it means that the number 60 is indeed part of the text string in that cell.

### Example #5: Using ISNUMBER to Validate Data Entry

ISNUMBER can be used to validate data entry. For instance, if you want to ensure that a cell contains only a number, you can use ISNUMBER in data validation. If you want to ensure that only numbers are entered in cell E5, you could set up a data validation rule with the formula =ISNUMBER(E5). Users who try to enter anything other than a number in cell E5 will receive an error message.

These examples highlight the versatility of the ISNUMBER function in Google Sheets. Whether you’re validating data, searching for numbers within text, or simply identifying numeric cells, ISNUMBER can be a powerful tool in your spreadsheet toolbox.

## ISNUMBER: Common Mistakes & Problems

When using the ISNUMBER function in Google Sheets, there are a few common mistakes and problems that users frequently encounter. Understanding these potential pitfalls can help you avoid them and use the function more effectively.

**Incorrect Syntax**: This is one of the most common errors users make. The ISNUMBER function requires a specific syntax to work correctly. The function will not return the expected result if the syntax is incorrect. For instance, instead of typing =ISNUMBER(A1), some users might type =ISNUMBER A1 or =ISNUMBER “A1”, both of which are incorrect.**Using ISNUMBER with Non-Numeric Data**: If you use ISNUMBER on a cell that contains non-numeric data, such as text or a date, the function will return FALSE. This is not a mistake per se, but it might lead to confusion if you’re not aware of it.**Forgetting About Decimal Numbers**: ISNUMBER will return TRUE for decimal numbers. Some users assume it only works with whole numbers, but this is not true.**Confusion with Other Functions**: Some users confuse ISNUMBER with other similar functions, such as ISNUM or ISTEXT. These functions have different purposes, and using them interchangeably can lead to errors.**Ignoring Locale and Formatting Settings**: The way numbers are formatted can vary depending on your locale settings. For example, in some regions, a comma is used as the decimal separator, while a period is used in others. If your spreadsheet uses a different setting than what you’re used to, ISNUMBER might not work as expected.

## Why Is ISNUMBER Not Working? Troubleshooting Common Errors

If you’re utilizing the ISNUMBER function in Google Sheets and find it’s not working as expected, you may encounter one of several common errors. Each error has a specific cause and a straightforward solution. Let’s delve into these errors, their causes, and how to solve them.

### #VALUE! Error

**Cause**: The #VALUE! error occurs when the ISNUMBER function is used with a value that is not recognized as a number. This could be text, a date, or a Boolean value.

**Solution**: To resolve the #VALUE! error, ensure that the value you’re using with the ISNUMBER function is a number or a cell reference that contains a number. If you’re not sure whether a cell contains a number, you can use the ISTEXT function to check if the cell contains text and the ISDATE function to check if it contains a date.

### #REF! Error

**Cause**: The #REF! error typically occurs when the cell reference provided to the ISNUMBER function is invalid. This could be because the referenced cell has been deleted or moved.

**Solution**: To solve the #REF! error, ensure the cell you’re referencing in your ISNUMBER function still exists in your spreadsheet. If it doesn’t, correct the cell reference in your formula.

### #NAME? Error

**Cause**: The #NAME? error is displayed when Google Sheets doesn’t recognize the text in the formula. This could be due to a typo in the ISNUMBER function name or the cell reference.

**Solution**: To fix the #NAME? error, check your spelling and syntax. Make sure you’ve typed “ISNUMBER” correctly and that your cell references are correct. Use a comma to separate function arguments.

### #DIV/0! Error

**Cause**: The #DIV/0! error is not directly related to the ISNUMBER function, but it may appear in your spreadsheet if you’re using ISNUMBER in combination with a division operation. This error is displayed when a number is divided by zero, which is not possible in mathematics.

**Solution**: To fix the #DIV/0! error, ensure that your formula isn’t trying to divide a number by zero. You could use the IF function to check if the denominator is zero before performing the division operation.

### #N/A Error

**Cause**: The #N/A error is typically displayed when the ISNUMBER function is combined with a lookup function (like VLOOKUP or HLOOKUP), and the lookup value is not found.

**Solution**: To resolve the #N/A error, ensure that your lookup value exists in the lookup range. If you’re not sure whether a value exists, you can use the MATCH function to check. If MATCH returns an error, the lookup value doesn’t exist in the lookup range.

## Using ISNUMBER With Other Google Sheets Functions

Combining ISNUMBER with other Google Sheets functions can result in a more powerful tool for data analysis. This section will detail how ISNUMBER can be used with other functions, such as IF, SUM, and ARRAYFORMULA.

### With IF

The IF function in Google Sheets is used to perform logical tests and return different values based on the results of these tests. By combining it with ISNUMBER, you can check if a certain cell contains a number and return a specific result based on that.

**Example**:

**=IF(ISNUMBER(A1), “This is a Number”, “This is not a Number”)**

In this example, if cell A1 contains a number, the formula will return “This is a Number”. If cell A1 doesn’t contain a number, it will return “This is not a Number”.

### With SUM

The SUM function is used to add up values in Google Sheets. When combined with ISNUMBER, it can be used to add up only the cells that contain numbers.

**Example**:

**=SUM(IF(ISNUMBER(A1:A10), A1:A10, 0))**

In this example, the formula will add up all the numbers in the range A1 to A10. If a cell in this range does not contain a number, it will be treated as 0.

### With ARRAYFORMULA

The ARRAYFORMULA function allows you to apply a formula to an entire range of cells. When used with ISNUMBER, you can check a whole range of cells to see if they contain numbers.

**Example**:

**=ARRAYFORMULA(IF(ISNUMBER(A1:A10), “Number”, “Not a Number”))**

In this example, the formula will check each cell in A1:A10. If a cell contains a number, it will return “Number”. If a cell does not contain a number, it will return “Not a Number”.

For more details on the ISNUMBER function, check out the official documentation at the Google Docs Editors Help Center.