Global Document Type Identifier (GDTI)

A GDTI is the GS1 Identification Key used to identify important documents by type. This unique identifier is comprised of a GS1 Company Prefix, a Document Type, a Check Digit, and an optional serial number.

Note: The term “document” is applied broadly to cover any paper or digital file. The issuer of the document is normally responsible for all the information contained within the document, both in a barcode and in Human Readable Interpretation (HRI) and/or an EPC-enabled RFID tag.

The use of GDTIs provides organisations with a method for identifying documents both internal and external to the organisation.

They are:

  1. Globally unique

  2. Simple to use

  3. Multi-sectorial

There are a number of benefits to using the GDTI to identify important documents:

  • The structure of the GDTI and its assignment rules are administered by GS1, supported by implementation guidance, business examples, and maintenance

  • GDTI is a simple coding system used to facilitate document numbering and identification with almost limitless capacity

  • Already an established standard for identifying important documentation, the GDTI uses the same GS1 standards that are used in many other business applications. If you are already using GS1 standards to identify products or locations, it’s easy to extend your use to identify important documents as well.

  • GDTIs are unique worldwide. A GDTI can be used throughout the world with no need for trading partner(s) to assign proprietary numbers to ensure uniqueness.

  • The GDTI can identify a document uniquely if required

  • The GDTI enables companies to scan a document in order to retrieve or track the key data

  • The GDTI allows the issuer, rather than a third party, to allocate GDTIs

  • The GDTI guards against mis-identification and fraud

  • The GDTI is an easily defined data structure with integrity checking that facilitates processing and transmission of data

  • GDTIs can be encoded in GS1-128 or GS1 DataMatrix barcode symbols and/or EPC-enabled RFID tags and in human-readable text

The GDTI is a simple tool used to identify documents. Where required, the GDTI can identify documents uniquely. The issuer of a document is normally responsible for all the information contained within the document, including both barcoded and Human Readable Interpretation (HRI) information. Such documents typically require storage of the appropriate information contained on the document. A company will issue a GDTI when it is important to maintain a record of the document. The GDTI will provide a link to the database that holds the “master” copy of the document. If your business issues documents that require tracking and control, GDTI can be used to enable this capability. A GDTI can be assigned by a company anywhere in the world and can be used anywhere in the world. Any important documents that has a need to be tracked can be identified and applications built to capture the information using GDTI as the key.

Some examples of document types that may be identified using a GDTI include:

  • Land registration papers identifying the property

  • Tax demands identifying the claim

  • Electronic messages

  • Insurance policies identifying the holder and coverage

  • Exam papers for schools

  • Proof of shipment forms

  • Passports

  • Digital files

  • Enhanced driver’s licenses

  • Identification of television commercials

  • Internal invoices

The GDTI may be produced as a GS1-128 and GS1 DataMatrix barcode, encoded in an Electronic Product Code (EPC®)–enabled Radio Frequency Identification (RFID) tag, and printed on the document as a method of identification or for detail or information retrieval.

A GDTI is formed with the following components:

  • APPLICATION IDENTIFIER (AI): AI (253) to indicate GDTI

  • GS1 COMPANY PREFIX: A globally unique number allocated to a GS1 member company

  • DOCUMENT TYPE: The number assigned to identify the type of document

  • CHECK DIGIT: A modulo-10 check digit used to check for input errors

  • SERIAL NUMBER: An optional alpha-numeric identification for individual document


The following steps are used to form GDTIs:

  1. Start with your GS1 company prefix

Your GS1 Company Prefix is the globally unique number allocated to your company by GS1 Australia or another GS1 Member Organisation.

  1. Create the document type

The Document Type is a number assigned by you, the holder of the GS1 Company Prefix, to uniquely identify a type of document within your company. The Document Type varies in length as a function of the GS1 Company Prefix length. Note that the combined length of the GS1 Company Prefix and Document Type is always 12 digits.

Hint: Assign your Document Types sequentially, and do not build any intelligence into the number. The scheme that defines a particular document type range as having a set meaning today will mean nothing a short time into the future when your company reorganizes, buys or merges with another firm, or another staff member takes over GDTI assignment duties.

  1. Calculate the check digit

The Check Digit is a calculated one-digit number used to ensure data integrity. Find out how this digit is calculated.

4. (Optional) assign the serial number: The serial number gives you the option of tracking not only specific document types, but also specific instances of each document type (i.e., not just a land registration document, but this specific land registration document). You can assign up to a 17- character alpha-numeric serial number for each GDTI. Again, we recommend assigning serial numbers sequentially, not building any type of intelligence into the serial number itself.

If a document identified by a GDTI changes, a separate, unique GDTI is required whenever any of the characteristics of a document are different in any way that is relevant to the business process