The "UPC-A barcode" is by far the most common and well-known symbology, at least in the United States. An UPC-A barcode is the barcode you will find on virtually every consumer good on the shelves of your local supermarket, as well as books, magazines, and newspapers.

UPC-A encodes 11 digits of numeric (0 through 9) message data along with a trailing check digit, for a total of 12 digits of barcode data. An example of a typical UPC-A barcode is:

EAN-13 - Article Numbering System (EAN) in Europe

EAN-13, based upon the UPC-A standard, was implemented by the International Article Numbering System (EAN) in Europe. This standard was implemented mostly because the UPC-A standard was not well designed for international use, but probably partly because no-one likes the U.S. to be in charge of anything-especially the Europeans. :)

EAN-13 is a superset of UPC-A. This means that any software or hardware capable of reading an EAN-13 symbol will automatically be able to read an UPC-A symbol. The only difference between EAN-13 and UPC-A is that the number system code in UPC-A is a single digit from 0 through 9 whereas an EAN-13 number system code consists of two digits ranging from 00 through 99, which is essentially a country code. Each country has a numbering authority which assigns manufacturer codes to companies within its jurisdiction. The manufacturer code is still five digits long, as is the product code, and the check digit is calculated in exactly the same way.

Number System: The number system consists of two digits (sometimes three digits) which identify the country (or economic region) numbering authority which assigned the manufacturer code. Any number system which starts with the digit 0 is a UPC-A barcode. The valid number system codes are presented in the following table: