UPC and EAN barcodes are used around the world in point-of-sale scanning environments for item identification. They are remarkably similar. UPCs are commonly on US & Canadian branded products and EANs are used for product identification for all other countries. Both UPCs and EANs are under the GS1 standards umbrella and encode GTIN numeric data. The most immediate visual difference between UPC and EAN barcodes is the number of digits encoded within each. A UPC encodes 12 digits (GTIN-12) and an EAN encodes 13 digits (GTIN-13).
Even though UPC barcodes display 12 numeric digits in the human-readable text below the symbol, there is an additional zero encoded within the bar/space pattern. In fact, the GTIN encoded in a UPC can technically be displayed in an EAN barcode and the bar/space pattern would be identical. As shown below, each image shows the representation of GTIN 0037000000013 and both barcodes have 30 total bars in the same pattern.
There is really NEVER a reason to encode a UPC (GTIN-12) as an EAN. In fact, many online companies offering "discounted UPCs" are so unaware of the standards that they provide their clients with both versions of the codes they are trying to resell. It is usually a telltale sign that companies should stay away.
The beginning segment of UPC (US & Canada) and EAN barcodes are comprised of an assigned Company Prefix from the local GS1 numbering office of each country. The prefix assignments by each local country office begin with a specific 3-digit prefix (Country Code).
It is important to note that companies license prefixes based on where their primary offices are located and NOT where products are manufactured. A company such as Levi's, manufactures shoes and clothes from various factories around the world but their products are normally marked with UPC barcodes.
The first point-of-sale barcode scanned was a pack of Wrigley's gum at a Marsh Supermarket in Ohio on June 26, 1974. The barcode was a UPC, which stands for universal product code and contained the common 12 digits. By definition, a UPC can be scanned universally around the globe.
At the time, the standards organization was called the UCC (Uniform Code Council). Their role consisted of creating standards for US product identification and barcode. At the same time around the globe, there were individual EAN (European Article Number) offices working off of similar constructs. The key difference was that EANs encoded 13 digits and UPCs encoded 12 digits. As global commerce expanded, manufacturers outside of the US were challenged with separately identifying their products with both UPC and EAN barcodes. Although the products from US companies marked with UPC barcodes could be scanned around the world, the EAN barcodes from other countries could not be scanned in the US. The scanners in the US were originally programmed to only read 12 digits and the 13-digit EAN barcode caused problems.
As other non-grocery industries adopted UPC/EAN barcodes, multinational companies were also challenged with minor differences between the varying barcode standards from different countries. Consequently, the Uniform Code Council and all of the EAN offices combined into a single entity called GS1 with individual country offices. There is one global standard that all of the offices contribute towards and market. At the same time, they established the 2005 Sunrise Date which addressed the acceptance of 13-digit barcodes at US retail scanners. After this period, each company only needed to mark their products with a single type of barcode that was scannable worldwide.