This function, Is Error of Any Kind, tests whether a value, an expression, or contents of a referenced cell has an error of any kind.
ISERROR(cellreference)
ISERROR(value)
ISERROR(expression)
Specify a cell reference, a numeric or text value, or an expression for the argument.
Use this function to test the contents of a cell, a numeric or text value directly, or a function or expression.
This function returns TRUE if the value refers to an empty cell or to no data.
Accepts any data type for an argument. Returns Boolean (TRUE or FALSE) data.
ISERROR(B12)
ISERROR(R12C2)
ISERROR(#N/A) gives the result TRUE
ISERROR(#REF!) gives the result TRUE
ISERROR(C14) gives the result TRUE if C14 contains a #NUM! error.