An item number is used to identify, differentiate, categorize, and uniquely identify commercial items. It is only assigned once for a specific item or a specific variant of the corresponding item. This uniqueness and unambiguity refers to the respective underlying system. This can be the company’s own product range, its own warehouse or a globally valid standard. Such systems are also called item coding systems and can be created both individually and across companies. In the former case, companies have developed and established their own item numbers, while international standards are used in the latter. There are different ways to compose and display an item number or item code. The best-known form of presentation is the bar code, also known as a barcode. In the EAN system or the GTIN system, the item number usually consists of four segments with a total of 13 digits, which have different levels of significance and are arranged as follows:

• digits 1-3 identify the country
• digits 4-7 identify the company
• digits 8-12 identify the article
• Digit 13 is used only as a check digit

Every item is subject to this numbering. In addition, there are the correspondingly different thin and thick lines in the barcode, which are read by scanners.

The most common international item numbers include EAN, GTIN, UPC and ISBN. An example of an item number that is known across companies but only used within companies is Amazon’s ASIN (Amazon Standard Identification Number). The ASINs are relevant for managing the product catalog on Amazon. The ASIN makes it possible to present the most appropriate search result possible to the buyer’s search, making it easier for buyers to find products. In addition, ASINs help protect products from counterfeiting.

The International Standard Book Number (ISBN) is a unique item number assigned to books and other stand-alone publications that include editorial content. This may also include software or multimedia products. Originally 10 digits long, it now has 13 digits, which is due to the fact that, on the one hand, the number range has been greatly increased and, on the other hand, compatibility with the EAN system has been achieved. This means that a 13-digit ISBN is identical to the corresponding EAN.

The EAN code (European Article Number) is the most widely used item number and was renamed GTIN in 2005. Both are accompanied by a corresponding barcode.

The GS1 standard and its advantages

When it was introduced in 1976, the aim was to ensure that the EAN was a Europe-wide unique identifier for items. After only a few years, the EAN coding was also used in Asia, Africa, Australia and South America. In 2002, the EAN was merged with the North American equivalent UPC (Universal Product Code) to form the current GS1 (Global Standards 1). As a result, a new term was established for the compatible EAN and UPC identification systems: GTIN (Global Trade Item Number).

The GTIN allows the entire value chain to be permeated by a single item number system. The GS1 standard is already firmly anchored in the production process, in that every single item from procurement to production to the end product is assigned a unique item number, the GTIN. Further information on processes such as warehousing, transportation, retail, delivery and returns are all generally stored on the GS1-Standard 128 code variant. This means that each item receives a unique label that identifies it within a specific packaging hierarchy. In addition to the batch number and, for example, the shelf life, other data such as the item description, transport unit, identification and classification number, lot number and net weight can also be stored.

Advantages of the GS1 standard:

• Fast recording at goods receipt or in the midst of the flow of goods
• Flexible and fast creation of data carriers and labels
• Cost-effective data storage medium
• Can be combined with plain text on the same data storage medium
• 16,000 and more scans per second, at a conveyor speed of 2.3 meters per second
• Proven error-free barcode capture
• Fewer manual processes, more automation instead
• Data synchronization at a collection station in real time

Beyond the penetration of item numbers along a value chain and their internal use, various advantages of item numbers can be derived in general, especially in retail, both stationary and online. Item numbers ensure and enable:

• The flawless, unambiguous definition of items
• Avoiding product mix-ups
• Automating warehousing
• Optimizing the movement of goods
• Global standardization

Particularly in e-commerce, i.e. online retailing, the item number is a prerequisite for being listed on platforms and marketplaces such as Amazon and being able to sell there. In distribution centers or systems, different item numbers can also refer to the same item at different locations (warehouse locations). In addition to their use in warehousing and the corresponding internal inventory control, item numbers are also used at scanner cash registers, where they are read into the merchandise management system in order to be able to record and bill items at the time of sale.

Article numbers and the corresponding article numbering systems are used to clearly identify or classify articles within or between companies. This makes it possible to rationalize the flow of goods between industry, trade and consumers, as well as to control closed merchandise management systems and make them more efficient. The most widely used item number is the EAN (European Article Number), which is affixed to the product as a bar code or barcode by means of a label, making it machine-readable. Meanwhile, the EAN system and its North American counterpart, the UPC (Universal Product Code), have been merged to form the GTIN, the Global Trade Item Number. Despite the change in terminology, the term EAN is still used synonymously. With the GTIN, each product or product variant can be clearly and globally identified. It is used wherever products are subject to automatic recording and processing and must be labeled. It is a central module of merchandise management and makes it possible to control supply and delivery processes in a targeted manner. Item numbers now permeate the entire value chain, from warehousing to production and sales.

Further reading recommendations:

• Overview of identifiers
• Structure and use of barcodes
• What is a Serial Shipping Container Code?
• The electronic coding technology EPC