ISERROR Function in Excel
The ISERROR function checks if a value or formula results in any Excel error and returns TRUE or FALSE. Master error detection and handling.
Excel
Google SheetsExcelGoogle Sheets=ISERROR(value)Quick Answer
ISERROR function ISERROR function tests if a value or formula returns any error in Excel and Google Sheets, returning TRUE for all error types and FALSE otherwise. Syntax: `=ISERROR(value)`.
=ISERROR(value)- Saves 75% time vs manually checking multiple error types
Practical Examples
Basic Error Detection
Check if a division operation produces an error
Custom Error Message for VLOOKUP
Replace #N/A errors with user-friendly messages
Validate Multiple Calculations
Check if any calculation in a row contains errors
Conditional Formatting with Error Detection
Highlight cells containing formula errors
Count Errors in a Range
Determine how many cells in a range contain errors
Nested Error Checking with Multiple Criteria
Build complex error handling with multiple fallback options
Common Errors and Solutions
ISERROR function not recognized
Function name is misspelled or Excel doesn't recognize it
1. Verify the spelling is exactly 'ISERROR' (all capitals or lowercase) 2. Check there are no extra spaces before or after the function name 3. Ensure you're using a version of Excel that supports this function (Excel 2003 or later) 4. Try entering the formula in a different cell to rule out cell-specific corruption
Use Excel's autocomplete feature by typing =ISER and pressing Tab when ISERROR appears in the suggestion list
Example:
ISERROR returns FALSE when you expect TRUE
The value being tested is not actually an error, or the error is being caught by another function first
1. Check if the cell reference or formula you're testing actually contains an error 2. Verify that functions like IFERROR aren't suppressing the error before ISERROR can detect it 3. Test the value directly to see what it returns: try entering just the formula without ISERROR 4. Use Excel's formula auditing tools (Trace Precedents) to verify what value is being passed to ISERROR
Always test your base formula first before wrapping it in ISERROR to ensure errors are occurring as expected
Example:
ISERROR requires exactly 1 argument
The required 'value' parameter is missing from the function
1. Add a cell reference, value, or formula inside the parentheses 2. Check for missing commas if you intended to test multiple values (use separate ISERROR functions) 3. Verify the formula isn't incomplete due to a typing error 4. Remember that ISERROR takes exactly one argument - use OR/AND to test multiple values
Always provide a value, cell reference, or formula to test: =ISERROR(A1) or =ISERROR(VLOOKUP(...))
Example:
Formula creates a circular reference
The formula refers back to its own cell, creating an infinite loop
1. Move the ISERROR formula to a different cell than the one being tested 2. Use helper columns to break the circular logic into separate steps 3. Review your formula structure to eliminate self-references 4. If intentional, enable iterative calculations in Excel Options (not recommended for most cases)
Never test a cell's own value with ISERROR in the same cell. Use a separate cell to test another cell's result.
Example:
Best Practices and Advanced Tips
Prefer IFERROR for Cleaner Code
While ISERROR is powerful, modern Excel offers IFERROR which combines error detection and replacement in one function. Instead of =IF(ISERROR(formula),"fallback",formula), simply use =IFERROR(formula,"fallback"). This reduces formula length by 50% and improves readability while maintaining the same functionality. However, use ISERROR when you need to detect errors without immediately replacing them, such as in conditional formatting or data validation rules.
Combine with Specific Error Functions
For more precise error handling, combine ISERROR with specific error type functions like ISERR (excludes #N/A), ISNA (only #N/A), or error-specific logic. This allows different responses to different error types. For example, #N/A might mean "not found" (recoverable), while #REF! indicates a broken formula (needs immediate fixing). Use nested IF statements with multiple IS functions for granular error handling.
Use in Array Formulas for Bulk Validation
Apply ISERROR to entire ranges using array formulas to validate multiple cells simultaneously. In Excel 365 or Google Sheets, =ISERROR(A1:A100) creates an array of TRUE/FALSE values corresponding to each cell. Combine with SUM, COUNTA, or conditional formatting to analyze error patterns across large datasets. This is especially useful for identifying data quality issues in imported files or user-entered data before running complex calculations.
Don't Suppress Errors During Development
While ISERROR helps create user-friendly spreadsheets, avoid using it during formula development and debugging. Visible errors like #REF!, #DIV/0!, and #N/A provide crucial information about formula problems. First, build and test your formulas until they work correctly, then add ISERROR-based error handling as a final polish. Premature error suppression can hide bugs and make debugging significantly harder.
Create Smart Data Validation Rules
Use ISERROR in custom data validation formulas to create sophisticated input rules. For example, =NOT(ISERROR(VLOOKUP(A1,ValidCodes,1,FALSE))) only allows values that exist in a lookup table. Or =NOT(ISERROR(A1/B1)) ensures both cells contain numbers compatible with division. This prevents errors before they occur by rejecting invalid input at the source, maintaining data integrity proactively.
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Example Excel formula:
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