For example a UPC-E barcode with the number 654321 would expand to the UPC-A 065100004327 or 165100004324, depending on the parity pattern of the encoded digits, as described next.
UPC-E check digits are calculated using this expanded string in the same way as used by UPC-A. The resulting check digit is not added to the barcode, however, but is encoded by manipulating the parity of the six digits which are present in the UPC-E - as shown in the following tables: