## Purpose

## Return value

## Syntax

`=ISNA(value)`

*value*- The value to check if #N/A.

## How to use

The ISNA function returns TRUE when a cell contains the #N/A error and FALSE for any other value, or any other error type. The ISNA function takes one argument,* value*, which is typically a cell reference.

### Examples

If A1 contains the #N/A error, ISNA returns TRUE:

```
=ISNA(A1) // returns TRUE
```

ISNA returns FALSE for other values and errors:

```
=ISNA(100) // returns FALSE
=ISNA(5/0) // returns FALSE
```

You can use the ISNA function with the IF function test for #N/A and display a friendly message if the error occurs. For example, to display a message if A1 contains #N/A and the value of A1 if not:

```
=IF(ISNA(A1),"message",A1)
```

The IFNA function is a more efficient way to trap the #N/A error. See VLOOKUP without NA error for an example.

### Return #N/A

To explicitly return the #N/A error in a formula, you can use the NA function:

```
=NA() // returns #N/A error
```

The following will return true:

```
=ISNA(NA()) // returns TRUE
```

### Count #N/A errors

To count cells in a range that contain #N/A errors, you can use the SUMPRODUCT function like this:

```
=SUMPRODUCT(--ISNA(range))
```

The double negative coerces the TRUE and FALSE results from ISNA into 1s and 0s and SUMPRODUCT sums the result.

### Notes

- The IFNA function is a more efficient way to trap and handle the #N/A error.