ReferenceExcel FormulasSupported FormulasISNAOn this pageISNA The ISNA function checks if a value is the #N/A error value. Syntax =ISNA(value) Parameters value: The value to test Examples =ISNA(NA()) // Returns TRUE=ISNA(1/0) // Returns FALSE (different error)=ISNA("N/A") // Returns FALSE (text, not error)