The code of the container

With an estimated 25 million shipping containers moving around the world via sea, road and rail at any given time, do you ever wonder how we keep track of them?

Each shipping container is given it’s very own unique individual identification number, which is known as the container number. Without this special combination of letters and numbers, we would be completely lost.  This number is located on the sides of the containers, the container doors, the roof and also the inside of the container.

Even before leaving the factory where the container is built, it is given it’s container number.

All numbers worldwide consist of several standardized elements: an owner code, an equipment category identifier, a serial number and a check digit. That’s four letters (alphas) and seven numbers.

The owner code consists of three letters and is assigned to a container operator (shipping line) on a fixed basis. Some examples of owner codes are as follows:

  • KKF –  K-line Forty foot containers
  • KKT –  K-line twenty foot containers
  • OOL –  OOCL containers
  • HLB – Hapag Lloyd

The equipment category identifier indicates what kind of equipment the container is.  A “U” after the owner code indicates that it is a container (unit).  This could be a GP (general purpose container), F/R (flat rack) or even an OT (open top container). Some other examples are:

  • J for detachable freight container-related equipment
  • Z for trailers and chassis

The six digits following the letters are serial numbers. These are assigned by the owner or operator and uniquely identify the container within that owner/operator’s fleet.

The seventh number, known as the check digit, consists of one numeric digit which provides the means of validating and recording the transmission accuracies of the owner code and serial number.  The check digit is computed by a conversion algorithm where the letters are converted into numbers.  If one of the letters or digits in a container number change, the check digit will also change.

We hope that you have enjoyed this article on how a shipping container is given it’s number.

Sources: Wiki and HapagLloyd