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 an error and display a friendly message when it appears.

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.

Usage notes

Use the ISNA function to check to check for #N/A errors. Normally, value is supplied as a cell reference. For example, if A1 contains #N/A, the following formula will return TRUE:

=ISNA(A1)

To explicitly force the #N/A error in a formula, you can use the NA function. The following will return true:

=ISNA(NA())

Notes:

ISNA is part of a group of functions called the "IS functions", which are often used to test the result of formulas for errors.
With Excel 2007+, the IFERROR function can provide simpler, less redundant error checking.
With Excel 2013+, the IFNA function can trap and handle #N/A errors specifically.

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