Which ISO standard governs container identification markings?

ISO 6346 governs the identification markings used on intermodal freight containers.

The standard establishes a globally recognized container identification system so boxes can be tracked and distinguished during shipping, rail transport, road haulage, and terminal handling. A typical code contains a three-letter owner code, a category identifier, a six-digit serial number, and a check digit used to verify that the number has been entered correctly.

The familiar letters and numbers painted on a container are therefore more than a simple asset tag. They support documentation, customs processes, inventory control, automated scanning, and the movement of containers between different transport modes. ISO 6346 also covers related marking requirements, including markings for certain containers with reduced stacking or racking capability.

ISO 668 is often confused with ISO 6346. ISO 668 primarily specifies the classification, dimensions, and ratings of freight containers, while ISO 6346 focuses on identification and marking. ISO 28000 addresses security-management systems, and ISO 9001 concerns quality management rather than container coding.