The Check Digit is calculated by a modulo-10 algorithm from all the other digits in the number. This method of calculating the check digit is applicable to GTIN-13, GTIN-8, GTIN-12 or zero suppressed GTIN-12 and Interleaved Two-of-Five (ITF) bar code symbology which depicts 14 digits that are built up from the GTIN-13 digits.