GDTI Check Digit Calculator

How GDTI Check Digit Calculator Works?

The GDTI Check Digit Calculator applies GS1 Modulus 10 to the 12-digit fixed part. It puts the result in position 13. GDTI means Global Document Type Identifier. The optional serial after the check digit is not part of the calculation.

1. 1Combine the GS1 company prefix with the document type to reach 12 digits.
2. 2Apply weights 1 and 3 alternately to the 12 document-type digits and total them.
3. 3Take (10 − (S mod 10)) mod 10 as the GDTI check digit in position 13.
4. 4Append an optional serial of up to 17 characters.

GDTI Check Digit Calculator Formula

The GDTI formula is d₁₃ = (10 − (Σ dᵢ·wᵢ mod 10)) mod 10.

S = (d₁ + d₃ + … + d₁₁) + 3 × (d₂ + d₄ + … + d₁₂)   (GDTI)
d₁₃ = (10 − (S mod 10)) mod 10   (GDTI)

• d₁…d₁₂ are the 12 GDTI payload digits (company prefix + document type).
• d₁₃ is the GDTI check digit.
• S is the weighted GDTI sum.

Payload:  401234500021
Weights:  131313131313
S = 36
Check digit = (10 − (36 mod 10)) mod 10 = 4
GDTI = (253) 4012345000214XYZ789

GDTI Check Digit Calculator Conversion Table

The GDTI conversion table maps document types to their fixed part, check digit, and full GDTI.

What is GDTI Check Digit Calculator?

A GDTI Check Digit Calculator is a tool that computes the check digit of a Global Document Type Identifier. A GDTI identifies a document type plus an optional serial for each issued copy.

Governments, insurers, and manufacturers use GDTIs for certificates, invoices, and legal records. The identifier is encoded with Application Identifier (253).

What are the uses of GDTI Check Digit Calculator?

There are 3 main uses of the GDTI Check Digit Calculator, including certificates, archive control, and document tracking.

• Certificates: Authorities number certificates of origin and conformity.
• Archive control: Records teams label physical and digital files.
• Document tracking: Logistics teams link shipping documents to consignments.