Syntax
ISERROR(value)
| Parameter | Description |
|---|---|
| value | Parameter of the ISERROR function. |
Examples
Check for any error
Formula
=ISERROR(A1/B1)
Returns TRUE if the division fails (e.g., B1 is 0 giving #DIV/0!, or either cell has an error). FALSE if the division succeeds.
Safe lookup
Formula
=IF(ISERROR(VLOOKUP(A1, D:E, 2, FALSE)), "Not found", VLOOKUP(A1, D:E, 2, FALSE))
Returns "Not found" if the VLOOKUP fails, otherwise returns the lookup result. Note: IFERROR is a cleaner alternative.
Error flagging column
Formula
=IF(ISERROR(C2), "Check this row", "OK")
Creates a validation column that flags rows where column C contains any error, helping with data quality audits.
Common Errors
#VALUE!
ISERROR itself never errors — it always returns TRUE or FALSE. That's the whole point of the function.
Tips
Prefer IFERROR
Instead of =IF(ISERROR(expr), fallback, expr) which evaluates the expression twice, use =IFERROR(expr, fallback) which is cleaner and faster.
Too broad sometimes
ISERROR catches ALL errors including #N/A. If you only want to handle #N/A (e.g., from a lookup miss), use ISNA instead to avoid masking real errors.
Debugging tip
Temporarily remove ISERROR wrappers when debugging. They can hide the actual error type — seeing #REF! vs #VALUE! vs #N/A tells you very different things.
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