How to use the Excel ISNA function

Summary

The Excel ISNA function returns TRUE when a cell contains the #N/A error and FALSE for any other value, or any other error type. You can use the ISNA function with the IF function test for #N/A and display a friendly message if the error occurs.

Purpose

Test for the #N/A error

Return value

A logical value (TRUE or FALSE)

Syntax

=ISNA (value)

Arguments

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

Version

Excel 2003

Usage notes

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.

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