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GTIN

General

Global Trade Item Number

The GS1 umbrella standard behind retail barcodes โ€” including UPC-A, EAN-8, EAN-13, and GTIN-14 โ€” each using the same checksum logic at a different digit length.

Definition

GTIN (Global Trade Item Number) is the umbrella standard the international standards body GS1 uses to describe the family of barcode formats used to identify retail products and trade items worldwide. Rather than being a single fixed-length number, GTIN covers several related formats โ€” EAN-8, UPC-A, EAN-13, and GTIN-14 โ€” that differ only in digit count but share the same underlying checksum logic.

UPC-A (12 digits) is the standard most familiar to shoppers in North America, while EAN-13 (13 digits) is the equivalent standard used across most of the rest of the world, including Europe and India. GTIN-14 extends the same numbering system to identify shipping cartons and cases rather than individual retail units. Because all of these formats share one checksum formula, a single validator โ€” like the GTIN / UPC / EAN Barcode Validator โ€” can check any of them.

Formula

Check Digit = (10 โˆ’ (ฮฃ weighted digits mod 10)) mod 10

Each digit (excluding the check digit) is weighted 3 if its position counting from the right is odd, and 1 if even โ€” the same rule regardless of total length.

Worked Example

For the UPC-A code 036000291452, the payload is 03600029145 and the check digit is 2.

Weighting from the right (3, 1, 3, 1, โ€ฆ): 5ร—3 + 4ร—1 + 1ร—3 + 9ร—1 + 2ร—3 + 0ร—1 + 0ร—3 + 0ร—1 + 6ร—3 + 3ร—1 + 0ร—3 = 58

Check digit = (10 โˆ’ (58 mod 10)) mod 10 = (10 โˆ’ 8) mod 10 = 2 โ€” matching the final digit, confirming the code is correctly formed.

Key Things to Know

  • One formula, many lengths: EAN-8, UPC-A, EAN-13, and GTIN-14 all use the identical weighted checksum โ€” only the total digit count differs.
  • Checksum โ‰  registration: a valid checksum confirms the number is well-formed, not that it's actually been issued to a real product by GS1.
  • UPC-A fits inside EAN-13: prefixing a UPC-A code with a zero produces an equivalent valid EAN-13 code.
  • GTIN-14 is for logistics, not retail shelves: it identifies cartons and cases, one level up from the barcode printed on an individual product.

Frequently Asked Questions

GTIN is the umbrella term GS1 uses for the entire family of retail product identifiers, while UPC and EAN are specific formats within that family โ€” UPC-A (12 digits) is standard in North America, and EAN-13 (13 digits) is standard internationally, including Europe and India. All of them use the same underlying checksum algorithm, just at different lengths.
GTIN-14 identifies cartons, cases, or pallets containing multiple retail units, rather than the individual product itself. It's used at the shipping and logistics level, distinct from the UPC or EAN printed on an individual item's packaging.
Starting from the digit immediately left of the check digit, each digit is alternately weighted 3 and 1, moving right to left; the products are summed, and the check digit is whatever value makes that sum a multiple of 10. This single formula works identically across all GTIN lengths.
No โ€” a passing checksum only confirms the number is mathematically well-formed, not that it has actually been issued by GS1 or assigned to a real product. Confirming real-world registration requires checking GS1's official database.
Yes โ€” adding a leading zero to a 12-digit UPC-A code produces a valid 13-digit EAN-13 code representing the same product, since EAN-13 was designed as a superset of the UPC-A numbering space.