The barcode symbol has two parts:

1) The machine-readable bar code (The bars)

2) The human-readable number   (the numbers below)

In this picture, the manufacturer identification number is the first six digits of the UPC number – (0)753182 in the image above. The next five digits — 95342 — are the item number.  The GS1 supplies 7, 8 and 9 digit manufacturer numbers as well.  The last number, 7, is the check digit.

The person that coordinates which barcode goes with which product is called a UPC coordinator. This person is responsible for assigning item numbers to products, making sure the same code is not used on more than one product, retiring codes as products are removed from the product line, etc.

Typically, every item that a manufacturer sells, in addition to every variation of the item requires a different item code. Since the barcode is also used to track inventory, it is important to have a different barcode for each of these variations. Using shoes as an example, a man’s oxford shoe may come in Black, Brown, and Cordovan, each in sizes, 9, 10, 11, 12, 13 and 14. Each of these variations (3 colors x 6 sizes = 18 different products)

 0:        Standard UPC number
1:         Reserved
2:         Random weight items (fruits, meat, vegetables, etc.
3:         Pharmaceuticals
4:         In store marketing for retailers (a store can set up unique barcodes for themselves, but no other store will be able to read them)
5:         Coupons
6, 7,8  Standard UPC number
9:         Reserved