Global Trade Item Number
Global Trade Item Number (GTIN) is an identifier for trade items developed by GS1 (comprising among others of the former EAN International and Uniform Code Council). Such identifiers are used to look up product information in a database (often by inputting the number through a bar code 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 8, 12, 13 or 14 digits long, and each of these 4 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 1-8). GTIN-8s will be encoded in an EAN-8 bar code. GTIN-12s may be shown in UPC-A, ITF-14, or GS1-128 bar codes. GTIN-13s may be encoded in EAN-13, ITF-14 or GS1-128 bar codes, and GTIN-14s may be encoded in ITF-14 or GS1-128 bar codes. The choice of bar code will depend on the application; for example, items to be sold at a retail establishment should be marked with EAN-8, EAN-13, UPC-A or UPC-E bar codes.
The EAN-8 code is an eight-digit bar code 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 4 zeros in the GTIN-12. The GS1 encoding/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-13||EAN·UCC-13, EAN-13, CIP|
|GTIN-12||EAN·UCC-12, UCC-12, UPC|
|Position of digits||T1||T2||T3||T4||T5||T6||T7||T8||T9||T10||T11||T12||T13||T14|
The numbering structure is as follows:
- T1 - Indicator digit, used for GTIN-14, "1" to "8" indicates a packaging level and "9" a variable measure item. Zero in this position is not considered an Indicator Digit, but rather a pad or fill zero. There is however, no worldwide consensus on which number indicates which packaging level and no significance should be built into this number.
- T2 through T13 GS1 Company Prefix & Item (product or service) reference number. The GS1 Company Prefix is allocated to the member company and the Item Reference is allocated by the user company. The length of each of these elements varies in length depending on the length of the allocated GS1 Company Prefix. Each different type of trade item is allocated a different number and, for ease of administration, it is recommended that companies do this sequentially (001, 002, 003, etc.).
- T14 is a check digit, which follows the standard modulo 10 calculation.
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 ISBN 10 number 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 pre-defined 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.
In February 2005, employees and booksellers of Barnes & Noble were informed that beginning at the end of March, their computer systems were going to add the ability to search by EAN to facilitate a switch over to the EAN (sometimes called ISBN 13 when used for books) from the current standard of ISBN 10 codes. Receipts will now list the EAN number, rather than the ISBN 10 number. Since all existing 10-digit ISBN codes are mapped to a subset of the space of 13-digit EANs, booksellers' computer systems will still be able to search by ISBN (and UPC in the music departments) to help booksellers locate older books that have not been assigned an EAN.
By January 1, 2005 the U.S. ISBN agency requires publishers be able to communicate ISBNs as GTIN-13s. The new 979 prefix for publications will be available on January 1, 2007 or upon eventual assignment of the last 978 prefix.
Each country has one or several blocks of GS1 Company Prefixes to assign.
Some special ranges exist. The usage for some is GS1 Member Organisation (GS1 MO) specific. The GS1 Company Prefixes that begin with the 3 digits listed below are used to construct what are considered RCN's (Restricted Circulation/Distribution Numbers) or are specific to a particular industry, such as the publishing industry:
- 020 – 029 Restricted distribution (GS1 MO defined)
- 040 – 049 Restricted distribution (GS1 MO defined)
- 050 – 059 Coupons
- 200 – 299 Restricted distribution (GS1 MO defined)
- 977 Serial publications International Standard Serial Number (ISSN)
- 978 – 979 Bookland International Standard Book Number (ISBN)
- 9790 International Standard Music Number (ISMN)
- 980 Refund receipts
- 981 – 982 Common Currency Coupons
- 990 – 999 Coupons
Comparison of UPC, EAN and GTIN 
The Universal Product Code, UPC, has been a dominant barcode standard in North America since it was established in the 1970s. It encodes a 12 digit number (GTIN-12), unique to a product, which allows it to be scanned and read in virtually any major retail establishment. A 6 "zero-suppressed" version (UPC-E) is available for items which are too small to allow the larger UPC-A version to be printed.
The EAN-13 and EAN-8 are other point of sale barcodes that are widely used outside of North America. A UPC formed in the United States can be transformed into an EAN by prefixing it with a zero.
The Global Trade Item Number, GTIN, is an identification number that may be encoded in UPC-A, UPC-E, EAN-8 & EAN-13 barcodes as well as other barcodes in the GS1 System.
See also 
- European Article Number - EAN
- Japanese Article Number - JAN
- Part number
- Universal Product Code - UPC
- An Introduction to the Global Trade Item Number (GTIN), Adobe PDF file
- Breakdown of GTIN structure - Informational site
- UPC and EAN symbol generation based on GTIN (informational)
- GTIN-14 GTIN-13, GTIN-12 and GTIN-8 generation
- More than 10 millions products with GTIN; sorted by country