Question 1

How do I find the shipping line from a container number?

Accepted Answer

The first four letters of a container number are the owner prefix, a BIC code registered to a shipping line or leasing company. This tool matches that prefix against a registry of major ocean carriers to name the line. If the prefix is not a carrier in the registry, the tool says so plainly rather than guessing.

Question 2

What is the ISO 6346 check digit?

Accepted Answer

ISO 6346 is the standard for container numbers: four letters (a three-letter owner prefix plus an equipment category letter), then a six-digit serial and a final check digit. The check digit is calculated from the other ten characters, so it can catch a typo. This tool recomputes it and tells you whether the number you entered is internally valid.

Question 3

Does a valid check digit mean the container is real?

Accepted Answer

No. A valid check digit only means the number is internally consistent, with no typo. It does not confirm that the container physically exists or is on a particular shipment. To track an actual container you need the carrier or a tracking platform.

Question 4

Why does the tool not recognize my container prefix?

Accepted Answer

Container prefixes are issued to many carriers and leasing companies worldwide. This tool covers the major ocean carriers. A prefix from a smaller line or a leasing company may not be in the registry, in which case the tool tells you plainly instead of guessing the owner.

Container number lookup and check-digit validator

Container number lookup

Container number questions

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