ReferenceExcel FormulasSupported FormulasISNUMBEROn this pageISNUMBER The ISNUMBER function checks if a value is a number. Syntax =ISNUMBER(value) Parameters value: The value to test Examples =ISNUMBER(123) // Returns TRUE=ISNUMBER("123") // Returns FALSE (text)=ISNUMBER(TRUE) // Returns FALSE (boolean)