Almost every product you buy today contains a barcode, known as a Universal Product Code (UPC). The UPC identifies the product and makes conducting transactions and maintaining inventory easier. The UPC is a 12-digit number made up of four sections, each identifying something about the product or the UPC code. The UPC is displayed as a barcode that a barcode reader can read and the corresponding numbers that a human can read. In the United States, UPC numbers are issued by GS1 U.S.

Look at the first digit. This is the product category. One of the most common digits is “0,” which usually represents a food item. Other digits mean: 1 - Reserved for future use 2 - Items sold by varying weight, such as meats and cheese. 3 - Drug and health items 4 - Used by stores for local needs 5 - Manufacturer coupons that can be doubled or tripled. 6 - General merchandise 7 - General merchandise 8 - Reserved for future use 9 - Manufacturer coupons that cannot be doubled or tripled.

Read the next five digits. These digits identify the product's manufacturer or distributor.

Look at the next five digits. This set of five digits identifies the specific product.

Identify the last digit. This digit is called the check digit. There is a mathematical formula the computer runs to make sure the UPC code was read correctly. The formula’s calculation will equal this digit if the system reads the UPC code correctly.