ISERROR Function Examples in Excel, VBA, & Google Sheets

This tutorial demonstrates how to use the ISERROR Function in Excel to test if a cell results in an error.

How to use the ISERROR Function

The ISERROR Function checks if a calculation results in an error.

=ISERROR(A2)

IF ISERROR Replaced by IFERROR

Prior to Excel 2007, the ISERROR Function was commonly used along with the IF Function to output a second calculation if the first calculation resulted in an error.

=IF(ISERROR(C2/B2),"Zero Stock",C2/B2)

However, in Excel 2007, the IFERROR Function was introduced, making the IF / ISERROR combo obsolete.

=IFERROR((C2/B2),"Zero Stock")

ISERR and ISNA

The ISERROR Function returns TRUE if any error occurs.

There are two other error checking “is” functions:

• The ISNA Function returns TRUE only for #N/A errors.
• The ISERR Function returns TRUE for all errors except #N/A errors.

=ISNA(A2)
=ISERR(A2)

Also, in addition to the IFERROR Function, there is the IFNA Function.

These functions are important because many formula errors are a result of bad formulas, but #N/A errors are often valid. For example, if you use the VLOOKUP Function and the lookup value is not found, the formula will return #N/A.

=VLOOKUP(A2,$D$2:$E$7,2,FALSE)

By applying the IFNA Function to the VLOOKUP, you can handle valid #N/A errors, while not handling other formula errors (so you don’t overlook those other errors).

=IFNA(VLOOKUP(A2,$D$2:$E$7,2,FALSE),VLOOKUP(A2,$G$2:$H$7,2,FALSE))

Other Logical Functions

Excel / Google Sheets contain many other logical functions to perform other logical tests. Here is a list:

IF / IS Functions
iferror
iserror
isna
iserr
isblank
isnumber
istext
isnontext
isformula
islogical
isref
iseven
isodd

ISERROR in Google Sheets

The ISERROR Function works exactly the same in Google Sheets as in Excel:

ISERROR Examples in VBA

You can also use ISERROR in VBA:

MsgBox IsError(1/2)

Result: False

MsgBox IsError(CvErr(0))

Result: True

This example shows using ISERROR to test the result of a function.

Function Divide(a As Double, b As Double)
    On Error GoTo error_handler
    Divide = a / b
    Exit Function
error_handler:
    Divide = CVErr(Err.Number)
End Function

Sub IsError_Example2()
    MsgBox "IsError(1/2) is " & IsError(Divide(1, 2))
    MsgBox "IsError(1/0) is " & IsError(Divide(1, 0))
End Sub

Result: IsError(1/2) is False
IsError(1/0) is True

Using IsError, you can check cells on Excel Sheet.

Sub CheckIfError(strRange As String)
    Dim cell As Range
    
    For Each cell In Range(strRange)
        cell.Offset(0, 1) = IsError(cell)
    Next
End Sub

Sub IsError_Example1()
    CheckIfError "C2:C5"
    CheckIfError "B9:B12"
End Sub