A GDTI consists of a 12‑digit base (GS1 company prefix + document type code + check digit) plus an optional 1‑18 digit serial number. The GDTI Checker validates the base structure and the modulo‑10 check digit automatically.
The Global Document Type Identifier (GDTI) is a GS1 standard for uniquely identifying document types and their electronic representations. It comprises a GS1 company prefix, a document type code, a check digit, and an optional serial number. Encoded in GS1‑128 or DataMatrix barcodes, GDTIs are widely used for inspection reports, waybills, insurance policies, electronic messages, and other critical documents. By using a GDTI, issuers can establish a reliable link from the barcode to their “master document” database, improving document management efficiency and security.
Three simple steps to verify your GDTI code:
You can try the example numbers to get a quick feel. If your input violates GS1 rules (e.g., wrong check digit or incorrect length), the GDTI Checker will give you a clear warning.
This tool is completely free, no registration required. It’s ideal for document managers, software developers, quality control specialists, and supply chain professionals.
The GDTI Checker only validates the structural integrity and check digit algorithm. A “valid” result means the identifier is technically compliant with GS1 standards. To confirm whether it corresponds to a real document, you still need to consult the issuing authority or official registry. Think of the GDTI as a “file number” – it provides a standardised, globally unique addressing scheme.
Common reasons: the number is shorter than 12 digits; it contains letters or symbols (GDTI must be all digits); or the check digit fails the modulo‑10 calculation. For example, if you enter 1234567890123, the GDTI Checker takes the first 12 digits (123456789012) and computes the weighted sum. If the final digit does not match the computed check digit, it is rejected.
This page is designed for single validation. If you have bulk requirements, you can integrate via our API endpoint /iso-checker by passing type=gdti&number=number to receive JSON results – perfect for embedding into document workflow pipelines.
The GDTI is a GS1 key specifically designed for “documents”, not limited to publications. It covers tax forms, driving licences, inspection reports, electronic invoices, and many other document categories. ISBN identifies books, ISSN identifies periodicals, while the GDTI is more general‑purpose and supports serial number extensions.
Not at all – it’s entirely free. OkeyTool is committed to providing practical online utilities for everyday use.
If you have further questions or spot any issues, please reach out via the contact information at the bottom of the page. Thank you for using the GDTI Checker!