The Global Trade Item Number ( GTIN) is an identifier for , developed by the international organization GS1. Such identifiers are used to look up product information in a database (often by entering the number through a barcode scanner pointed at an actual product) which may belong to a retailer, manufacturer, collector, researcher, or other entity. The uniqueness and universality of the identifier is useful in establishing which product in one database corresponds to which product in another database, especially across organizational boundaries.
GTINs may be eight, 12, 13, or 14 digits long, and each of these four numbering structures are constructed in a similar fashion, combining Company Prefix, Item Reference and a calculated Check Digit (GTIN-14 adds another component- the Indicator Digit, which can be 0–9). GTIN-8s will be encoded in an EAN-8 barcode. GTIN-12s may be shown in UPC-A, ITF-14, or GS1-128 barcodes. GTIN-13s may be encoded in EAN-13, ITF-14 or GS1-128 barcodes, and GTIN-14s may be encoded in ITF-14 or GS1-128 barcodes. The choice of barcode will depend on the application; for example, items to be sold at a retail establishment could be marked with EAN-8, EAN-13, UPC-A or UPC-E barcodes.
The EAN-8 code is an eight-digit barcode used usually for very small articles, such as chewing gum, where fitting a larger code onto the item would be difficult. Note: the equivalent UPC small format barcode, UPC-E, encodes a GTIN-12 with a special Company Prefix that allows for "zero suppression" of four zeros in the GTIN-12. The GS1 encoding and decoding rules state that the entire GTIN-12 is used for encoding and that the entire GTIN-12 is to be delivered when scanned.
|GTIN-14 (used for wholesale shipments, not retail point of sale)||EAN/UCC-14, SCC-14, DUN-14, UPC Case Code, UPC Shipping Container Code||GS1-128, GS1 Databar, ITF-14|
|GTIN-13||EAN, EAN·UCC-13, JAN (subset)||EAN-13|
|GTIN-12||EAN·UCC-12, UCC-12||UPC-A, UPC-E (condensed to 6 digits)|
Note that GTIN-12 and GTIN-13 numbers can be encoded as GTIN-13 or GTIN-14 by adding initial padding zeroes. For GTIN-14, this indicates a "packaging level" of a single item.
The numbering structure is as follows:
All books and serial publications sold internationally (including those in U.S. stores) have GTIN (GTIN-13) codes. The book codes are either constructed by prefixing the old 10-digit ISBN with 978, and recalculating the trailing check digit, or from 1 January 2007 issued as thirteen digits starting with 978 (eventually 979 as the 978 ranges are used up).
Each type of trade item is given its own GTIN, with the understanding that there is a potential need to retrieve predefined information from such items; this product or service may be priced, ordered, or invoiced at any point in the supply chain. This includes individual items as well as all of their different packaging configurations.