## Definition

Diving straight in, ISNUMBER is an Excel formula that checks if a cell contains a numeric value.

## Purpose

In the grand scheme of things, the ISNUMBER formula is utilized to determine if the value in a specific cell is a number. By doing this, it aids in separating numerical data from non-numerical data in your spreadsheets.

## Syntax

The syntax for the ISNUMBER formula is as straightforward as it gets:

`=ISNUMBER(value)`

## Parameters

ISNUMBER takes a single parameter: ‘value’. This can be a cell reference, a number you wish to verify, or even the result of another formula.

## Returns

Quite simply, ISNUMBER returns TRUE if the ‘value’ parameter is a number, and FALSE if it is not.

## Usage notes

The ISNUMBER formula is versatile and can be used in numerous scenarios where you need to validate the type of data. Do remember, however, that it also returns TRUE for dates, since Excel stores dates as numbers.

## Availability

Excel users will be pleased to know that the ISNUMBER formula is available in all Excel versions.

## Example #1

Let’s begin with a simple illustration. If cell A1 contains the number 10, the formula would be:

`=ISNUMBER(A1)`

This will return TRUE since A1 contains a number.

## Example #2

For our second example, let’s consider cell B2 contains the text ‘Excel’. In this case, the ISNUMBER formula:

`=ISNUMBER(B2)`

Will return FALSE because B2 contains text, not a number.

## Example #3

Now, let’s suppose cell C3 is empty. Applying the ISNUMBER formula:

`=ISNUMBER(C3)`

This will return FALSE since an empty cell does not contain a number.

## Example #4

In this example, let’s say cell D4 contains a date. If we apply the formula:

`=ISNUMBER(D4)`

This will return TRUE because Excel recognizes dates as numbers.

## Example #5

In our final example, let’s find out how many cells in a range (E1:E10) contain numeric data. Here’s how we do it:

`=SUMPRODUCT(--ISNUMBER(E1:E10))`

## Tips and tricks

To enhance your productivity, try combining ISNUMBER with other functions like IF and SUMPRODUCT to build more complex formulas.

## Limitations

The ISNUMBER function doesn’t differentiate between different types of numerical data, such as integers, decimals, and dates.

## Common errors and solutions

A common mistake is not realizing that ISNUMBER returns TRUE for dates because Excel treats dates as numbers. To avoid including dates, consider combining ISNUMBER with the ISTEXT and ISNONTEXT functions.

## Best Practices

For optimal results, always ensure you’re clear on the type of data you’re working with and the specific needs of your task. Mixing ISNUMBER with other functions can be very helpful.

## List of Related functions

Related functions to ISNUMBER include ISTEXT, ISNONTEXT, ISLOGICAL, ISERROR, ISNA, and ISBLANK.

## Frequently Used with the formulas

ISNUMBER often teams up with functions like IF, SEARCH, and SUMPRODUCT to create more advanced formulas.

## Frequently Asked Questions

### Q. Can the ISNUMBER function work on an array?

Yes, you can use the ISNUMBER function on an array.

### Q. How can I exclude dates when using ISNUMBER?

You can exclude dates by combining ISNUMBER with ISTEXT and ISNONTEXT functions.

### Q. Does ISNUMBER recognize error values?

No, ISNUMBER will return FALSE for cells containing error values.

By the end of this tutorial, you should be proficient in the use of the ISNUMBER formula. It’s an essential formula to know, particularly for anyone working with large sets of data in Excel.