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GTIN

GTIN (Global Trade Item Number) check digit calculation per GS1 standards. Unified format for product identification supporting GTIN-8, GTIN-12 (UPC), GTIN-13 (EAN), GTIN-14. Uses alternating weights (3,1) from right to left for global supply chain compatibility.

Properties

Property	Value
Category	Checksums
Sub-category	Product Identifier
Security status	🎓 Educational Only
Complexity	Beginner
Inventor	GS1 (formerly EAN/UCC)
Year	2004
Origin	Not specified
Source	algorithms/checksum/gtin-checksum.js

Security

Status: 🎓 Educational Only

No vulnerabilities are recorded for this implementation.

Notes

• GTIN-8: 8 digits (EAN-8, RCN-8)
• GTIN-12: 12 digits (UPC-A)
• GTIN-13: 13 digits (EAN-13)
• GTIN-14: 14 digits (shipping containers)
• Algorithm: Alternating weights 3,1,3,1… from right to left
• Sum odd positions (×3) + even positions (×1)
• Check digit: (10 - sum mod 10) mod 10
• Detects: All single-digit errors
• Detects: Most adjacent transposition errors
• Used globally in: Retail, logistics, e-commerce

Documentation

• GTIN on Wikipedia
• GS1 GTIN Standard
• GTIN Validation

References

• python-stdnum EAN/GTIN implementation

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — GTIN-13 example (9780201379624)

Field	Value
input	393738303230313337393632
expected	04

Vector 2 — GTIN-12 (UPC-A) example

Field	Value
input	3034393633343036333835
expected	02

Vector 3 — GTIN-8 example (96385074)

Field	Value
input	39363338353037
expected	04

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