ISERROR Function
Tests whether a value is any error.
Syntax
Parameters
| Parameter | Description | Required |
|---|---|---|
| value | The value, cell reference, or formula result to test. | Required |
Basic Example
Catch a divide-by-zero error
=ISERROR(1/0)1/0 produces #DIV/0!, which ISERROR detects.
Advanced Examples
Example 1: Test a cell that holds an error
A1 contains #N/A from a failed lookup.Detect any error in a cell
=ISERROR(A1)Example 2: Branch on error safely
Show a fallback when a calculation fails.Combine with IF to replace errors
=IF(ISERROR(A1/B1), "check input", A1/B1)How ISERROR Works
ISERROR returns TRUE when the value is any of the seven Excel error values, and FALSE for normal values. It is broader than ISNA (which catches only #N/A) and ISERR (which catches all errors except #N/A). To learn which error occurred, use ERROR.TYPE.
Important Notes & Limitations
Catches all errors including #N/A; use ISNA if #N/A is meaningful and should be left alone.
Does not identify which error occurred; use ERROR.TYPE for that.
Returns FALSE for ordinary values (not an error).
Common Errors & Fixes
Swallowing meaningful #N/AISERROR treats #N/A like any other error.Fix: Use ISNA or IFNA when #N/A should be handled differently.
Double computationIF(ISERROR(x),...,x) evaluates x twice.Fix: Use IFERROR, which evaluates the expression once.
Download Practice File
ISERROR
iserrorPractice ISERROR with Real Data
Download a sample CSV file with pre-populated data and practice exercises for the ISERROR function. Works in both Excel and Google Sheets.
File format: CSV (comma-separated values) - opens in Excel, Google Sheets, and all spreadsheet apps