ISERR function

The ISERR function in Excel checks whether a value or expression results in any error except #N/A. It returns TRUE if the value is an error (e.g., #DIV/0!, #VALUE!, etc.) and FALSE otherwise.

Syntax:

ISERR(value)

Arguments:

• value: The cell reference, value, or expression you want to check for an error.

Error Types Caught by ISERR:

• #DIV/0! (Division by zero)
• #VALUE! (Invalid value)
• #REF! (Invalid cell reference)
• #NAME? (Invalid function or name)
• #NUM! (Invalid numeric value)
• #NULL! (Null intersection)

Note: ISERR does not catch the #N/A error. Use ISERROR to catch all error types.

Examples:

Example 1: Division by zero

• Formula:

  =ISERR(1/0)
  

• Result: TRUE (since 1/0 results in a #DIV/0! error).

Example 2: Valid number

• Formula:

  =ISERR(100)
  

• Result: FALSE (since 100 is not an error).

Example 3: #N/A error

• Formula:

  =ISERR(NA())
  

• Result: FALSE (since #N/A is not caught by ISERR).

Use Cases:

1. Error Handling: Use in formulas to trap and manage specific errors:

   =IF(ISERR(A1/B1), "Error Detected", A1/B1)
   

   This avoids Excel’s default error messages and displays custom text instead.

2. Condition Checks: Test whether a formula or value results in an error other than #N/A.

Key Points:

1. ISERR vs. ISERROR:
   • ISERR excludes #N/A errors.
   • ISERROR includes all error types.
2. Error Trapping: For broader error management, consider IFERROR, which provides an easier way to handle errors:

   =IFERROR(A1/B1, "Error")