GTIN-8, GTIN-12, GTIN-13 and GTIN-14 identify trade items at different packaging levels.
Meaning and formats
GS1 manages the global identification system.
EAN and UPC
EAN-13 and UPC-A are members of the GTIN family.
Lengths
Valid structures contain 8, 12, 13 or 14 digits.
Barcode use
The bars are the machine-readable representation.