postal-logistics
UPU S10 (International Postal Standard) (UPU S10)
1D linear barcode standardizing international postal tracking numbers across 192 member countries (including India Post, USPS, Royal Mail), encoding 2 service indicator letters, 8 serial digits, 1 weighted Modulo-11 check digit, and 2-letter ISO country code.
Governing Specification: UPU Standard S10 / ISO/IEC 15417
Data Format & Required Fields
Encodes 13 alphanumeric characters (e.g. CP123456785US or EE123456785IN) rendered in Code 128. Enforces a weighted Modulo 11 checksum on serial digits.
Allowed Character SetEither 13-character S10 code (2 uppercase letters, 9 digits, 2-letter ISO country code) or 9-digit tracking number with valid Modulo 11 check digit.
Payload Length Rule Between 9 and 13 characters
Check Digit / Checksum Rule Requires a verified modulo-11 check digit to prevent scanner misreads and data transposition errors.
Example Valid Format
CP123456785USIndustry Guidance & Practical Applications
- International registered mail, air parcels, and EMS express items
- Cross-border customs and terminal dues postal exchange (CN22/CN23)
- Universal tracking across national postal administrations
Packaging & Scanning Notes: Governed by the Universal Postal Union (a specialized agency of the United Nations).
Symbol Constraints & Label Guidelines
- Must strictly conform to 13-character structure with valid UPU Modulo 11 check digit.