Skip to main content

ISERROR

Checks whether a value is an error and returns TRUE or FALSE.

Quick Example​

=ISERROR(A1/B1)

Returns TRUE if the division results in an error, FALSE otherwise.

Syntax​

=ISERROR(value)

Arguments​

  • value (required): The value to check for an error

Examples​

=ISERROR(A1)                         // TRUE if A1 contains an error
=ISERROR(1/0)                        // TRUE (#DIV/0! error)
=ISERROR("text")                     // FALSE (not an error)
=IF(ISERROR(A1), "Error", A1)        // Display "Error" or value

Error Types Detected​

  • #DIV/0! (division by zero)
  • #VALUE! (wrong type)
  • #REF! (invalid reference)
  • #NAME? (unrecognized name)
  • #NUM! (invalid number)
  • #N/A (value not available)
  • #NULL! (null intersection)

How It Works​

Returns TRUE For​

  • Any error value
  • Formula result that is an error

Returns FALSE For​

  • Numbers
  • Text
  • Blank cells
  • Logical values (TRUE/FALSE)
  • Dates

Does Not Propagate Errors​

Unlike most functions, ISERROR does NOT return the error itself:

=ISERROR(#DIV/0!)  // Returns TRUE (not #DIV/0!)

Common Use Cases​

  • Error checking: =IF(ISERROR(Formula), "Check input", Formula)
  • Conditional calculations: =IF(ISERROR(A1/B1), 0, A1/B1)
  • Data validation: =COUNTIF(A1:A10, ISERROR(A1:A10))
  • Clean displays: =IF(ISERROR(VLOOKUP(...)), "", VLOOKUP(...))

Comparison: ISERROR vs IFERROR​

Using ISERROR (Older Method)​

=IF(ISERROR(A1/B1), 0, A1/B1)

Evaluates formula twice.

=IFERROR(A1/B1, 0)

More efficient, evaluates once.

  • IFERROR - Return value if error (recommended)
  • IF - Conditional logic
  • ISBLANK - Check if blank
  • ISNUMBER - Check if number