Crux Systems Insights

What's in a shipping container number

October 23, 2017 by Hubert Yee |


There are 34.5 million shipping containers in the global fleet, and nearly 19 million containers enter the US every year carrying just about any type of product you can imagine. Using a unique number made up of four letters and seven digits assigned to each container, we track these shipments while they're in transit on ships and while they're being processed at terminals.

Looking at a container number alone, you can tell quite a bit about the container - if you know the code. Here's what those four letters and seven numbers assigned to each container actually mean.

Owner code: first three letters


The first three letters of a container number identify the owner/operator. This code is unique and is registered with the International Container Bureau.

Product group code: U, J, or Z


The next letter is used to identify the type of container. The letter U represents freight containers. The letter J identifies detachable freight container equipment, and the letter Z denotes trailers and/or chassis.

Registration number: next six digits


The next six digits represent an owner or operator's unique identification number for a container.

Check digit: last number


The last digit in the container number is the check digit number. It's used to confirm that the other numbers were properly transferred or recorded. There's a complicated calculation that is used to generate the check digit number - we'll leave the math behind it for another blog post.  

Given all that, it's a good thing you don't have to remember your container numbers. Simply add your containers to your watchlist, and we'll show you all of your containers status information in one place.

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