The ISERROR function is an information function which will return either TRUE or FALSE if the selected cell or values evaluate to any form of error code or if it evaluates to a valid value.

This is the format of the ISERROR function:

=ISERROR(REFERENCE OR FORMULA)

Here is an example of the ISERROR function:

=ISERROR(1/0) = TRUE

This function is valuable when calculating statistics or other equations which can easily find themselves resolving in error messages such as dividing by zero. Using ISERROR to circumvent these messages from appearing in your work.

An example of a functional implementation of this would be calculating trend in sales units. When the previous period encountered zero units sold, the current period will resolve to an error message unless these calculations can be avoided using ISERROR.

=IF(ISERROR(C2/C3), 0, C2/C3)