Summary

ISERR returns TRUE for Excel errors except #N/A. That means it catches problems like #DIV/0!, #VALUE!, and #REF!, but it leaves missing-lookup results alone.

This makes ISERR useful when #N/A is expected and meaningful, but everything else should be treated as a real problem. It sits in the middle between ISNA, which is very specific, and ISERROR, which catches everything.

Syntax

=ISERR(value)

You can test a cell reference, formula result, or direct expression. Like the other IS functions, ISERR returns only TRUE or FALSE based on the result it receives.

Arguments

• value - [required] The value, reference, or formula result you want to test.

ISERR vs Other Functions

Using ISERR

Use ISERR when you want to keep lookup misses visible but still trap broken formulas. That is the real difference between ISERR and ISERROR. If a missing lookup is part of normal flow, ISERR is often the better fit because it does not treat #N/A as the same kind of problem.

This makes ISERR helpful in audit sheets and data pipelines where "not found" is acceptable, but calculation errors and broken references are not. Instead of lumping everything together, you can react only to the errors that suggest the workbook needs repair or review.

A common pattern is to combine ISERR with IF and show a clean label when a formula is broken. That way, users see something readable instead of a raw Excel error code, while still letting #N/A pass through as its own separate signal.

Example 1 - Catch a Divide-by-Zero Error

This is a classic case for ISERR.

=ISERR(1/0)

Because 1/0 returns #DIV/0!, ISERR returns TRUE. This shows how the function reacts to a real formula problem that is not related to a missing lookup.

Example 2 - Ignore #N/A

This is what makes ISERR different from ISERROR.

=ISERR(B2)

If B2 contains #N/A, ISERR returns FALSE. That behavior is useful when #N/A is a normal "not found" result and should not be grouped with broken formulas.

Example 3 - Flag a Broken Formula

A real formula problem can be turned into a clearer status label.

=IF(ISERR(C3),"Broken Link","OK")

If C3 contains an error such as #REF! or #VALUE!, the formula returns "Broken Link". This helps separate actual workbook issues from ordinary lookup misses.

Example 4 - Catch a Type Mismatch

Text used in math often creates a non-#N/A error.

=ISERR("Text"*1)

This returns TRUE because the expression produces a calculation error rather than a missing-data error. It is a good example of the kind of problem ISERR is designed to catch.

Conclusion Recap

• Main job: ISERR catches errors except #N/A.
• Best use: Keep missing lookups separate from real formula problems.
• Common pair: Use it with IF for readable status labels.
• Important distinction: #N/A returns FALSE here on purpose.
• Use ISERROR instead: If you want to catch every error type, including #N/A.