# Shipping Container Code (ISO 6346) Key: `geography.transportation.iso6346` International shipping container identification code per ISO 6346. Owner code (3 uppercase letters) + equipment category (U, J, or Z) + serial number (6 digits) + check digit (1 digit). Total 11 characters. Page: Samples: `MSCU1234566`, `HLXU3456784`, `CMAU6543210`, `TRIU7890125`, `MSKU2345671` ## Background ### Origin ISO 6346 is the international standard titled Freight containers — Coding, identification and marking.[[1]](https://www.evs.ee/en/iso-6346-2022) The international register of identification codes for container owners was originated by the Bureau International des Containers (BIC) and has been published continually since 1970.[[2]](https://www.bic-code.org/bic-codes/) The International Organization for Standardization adopted the BIC owner-code register in 1972.[[2]](https://www.bic-code.org/bic-codes/) BIC describes its register as an essential part of the ISO 6346 standard.[[2]](https://www.bic-code.org/bic-codes/) BIC gives BICU 123456 5 as a theoretical example of a container code.[[2]](https://www.bic-code.org/bic-codes/) An owner code has to be registered with the Bureau International des Containers in Paris to ensure that it is unique worldwide.[[3]](https://en.wikipedia.org/wiki/ISO_6346) Wikipedia notes that an owner can apply for more than one owner code.[[3]](https://en.wikipedia.org/wiki/ISO_6346) ### Use To compute an ISO 6346 check digit, each letter is first given a numerical value, beginning with 10 for the letter A, with 11 and its multiples omitted.[[3]](https://en.wikipedia.org/wiki/ISO_6346)[[4]](https://containerhandbuch.de/chb_e/stra/stra_03_03_00.html) BIC says the check digit lets operators, terminals, depots and other parties in the supply chain validate container numbers automatically and catch errors from data entry or erroneous OCR readings.[[5]](https://www.bic-code.org/check-digit-calculator/) BIC warns that the check digit must be changed when a container is re-marked with a different BIC code.[[5]](https://www.bic-code.org/check-digit-calculator/) BIC notes that ISO 6346 also describes technical markings such as the size and type code, country code and various operational marks.[[2]](https://www.bic-code.org/bic-codes/) The Association of American Railroads recognises codes similar to ISO 6346 for containers and trailers travelling by rail in North America, but these are not recognised by BIC and lack check digits.[[3]](https://en.wikipedia.org/wiki/ISO_6346) When many numbers in a file fail the check digit, ask where the equipment came from before treating every failure as a typo. (Meridian's view) Wikipedia notes that many Customs Administrations have begun validating that containers are marked as per ISO 6346.[[3]](https://en.wikipedia.org/wiki/ISO_6346) ## Sources 1. [ISO 6346:2022 - EVS standard evs.ee \| en](https://www.evs.ee/en/iso-6346-2022) — catalogue entry 2. [Container BIC Code Lookup Tool \| BIC](https://www.bic-code.org/bic-codes/) — organisation 3. [ISO 6346](https://en.wikipedia.org/wiki/ISO_6346) — secondary source 4. [Container Handbook - Section 3.3 Identification system](https://containerhandbuch.de/chb_e/stra/stra_03_03_00.html) — secondary source 5. [Container Check Digit Calculator \| BIC](https://www.bic-code.org/check-digit-calculator/) — organisation