UPC Code is a 12-digit number assigned to a trade item with a barcode to identify products sold in stores. The UPC is used to identify the brands and also allow POS sytems to scan the item for easier checkout. It is also used to keep track of inventory within the POS system and stores. The UPC code is maintained by the Global Standards Organization (GS1), and each vendor can apply to obtain a 6-digit manufacturer identification number (MIN).

The MIN becomes first 6-digits of the UPC Code, the next 5-digits are arbitrarily assigned to products by the manufacturer as the item number, and the final digit is used as a checksum to validate the UPC code. The item number must be unique with the manufacturer, and the checksum is generated by modulating the sum of each digits.

The GTIN is a larger part of trade item identifaction number, which is used interantionally. There are 3 main family of GTIN Numbers.

• GTIN-12 (UPC-A): This is a 12-digit UPC code primarily used within North America.
• GTIN-8 (EAN/UCC-8): This is a 8-digit used outside of North America.
• GTIN-13 (EAN/UCC-13): This is a 13-digit used outside of North America.