JAN Generator
Append the GS1 modulus-10 check digit to twelve JAN data digits beginning with Japan's 45 or 49 GS1 prefix; this does not allocate a product code.
Description
Append the GS1 modulus-10 check digit to twelve JAN data digits beginning with Japan's 45 or 49 GS1 prefix; this does not allocate a product code.
JAN Generator handles the structural form and check-digit rules of the named identifier. Append the GS1 modulus-10 check digit to twelve JAN data digits beginning with Japan's 45 or 49 GS1 prefix; this does not allocate a product code.1
When to use JAN Generator
Use it to calculate a check digit for data digits that were assigned through the proper agency or GS1 process, or to prepare documented test fixtures.
How JAN Generator works
Append the GS1 modulus-10 check digit to twelve JAN data digits beginning with Japan's 45 or 49 GS1 prefix; this does not allocate a product code.1
How the identifier is processed
- Normalize permitted spaces and hyphens while retaining leading zeros.
- Check the exact length, character inventory, prefix rules, and variant-specific structure.
- Apply the standard check-digit or UPC zero-suppression rule and return the normalized result.
Limitations and assumptions
- A correct check digit proves only internal consistency; it does not prove that an agency assigned the identifier or that it belongs to a claimed product or publication.
- Leading zeros are significant and must not be removed by spreadsheet or numeric-field formatting.
- Registry ownership, company-prefix allocation, publication metadata, and barcode print quality require separate authoritative checks.
Alternative or Complementary approaches
Use the responsible ISBN, ISSN, ISMN, or GS1 registry to verify assignment and metadata. Use a barcode verifier when symbol dimensions, quiet zones, contrast, or scan reliability matter.
References
Similar or alternative tools
- ISBN Validator
Check structure and check-digit consistency.
- GTIN Validator
Check structure and check-digit consistency.