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HomeEducationWhat do the markings on a container mean..??

What do the markings on a container mean..??

The ubiquitous freight or shipping container has become an integral part of our lives not just if you are in the industry handling and moving these containers from point to point, but for all the businesses and industries that use the container..

It has been universally hailed as one of the greatest inventions of the modern world, one that completely changed the way in which business has been done since the 20th century and really and truly made the world a smaller place and the one true architect of Globalisation..

Exporters, importers, traders, packing houses, ports, customs, border authorities, police, clearing agents, freight forwarders, stevedores, hauliers, weighbridges ……………………….. and many more entities involved in a trade transaction may be seeing and handling a container on a daily basis..

But although many of these people see a container not everyone understands the many markings on a container..

The markings on a container play a very significant role in the movement of the container as they provide vital information to all entities in the supply chain relating to the monitoring and safety of the container and cargo during its carriage..

Let us look at each of the markings on a container individually using an example below..

what does the markings on a container door mean


1) Container Number – is of course the main marking on the door.. It is an alpha numeric sequence made up of 4 Alphabets and 7 Numbers..

The container number identification system has been created by the International Standards Organisation under their code IS06346:1995(E)..

As per this code, the container identification system consists of

  1. Owner code – 3 letters (in above example HLX)
  2. Equipment category – 1 letter (in above example, U denoting a freight container.. Other categories being J for detachable container-related equipment (such as Genset) and Z for trailers and chassis)..
  3. Serial number – 6 numbers (numbers ONLY)
  4. Check Digit – 1 number (numbers ONLY)

The owner code is UNIQUE to the owner of the container and the registration of this code rests with Bureau International des Containers et du Transport Intermodal (BIC)..

This is to avoid any duplication of code by any shipping line or container operator..

If you don’t know who a particular container belongs to, you can always do a BIC Code Search to identify the owner of the container..

But BEWARE, the owner of the container need not necessarily be operating the container as they could have leased the container to another operator or shipping line..


2) Check Digit – although it is part of the full container number, the check digit is a VERY IMPORTANT number as it can be used to identify if the above mentioned identification sequence is valid or invalid..

For example, if you go to BIC’s Check Digit Calculator and type in the prefix – HLXU and the numbers 200841, see what you get as the Check Digit..

Impressed yet..?? And here you thought that the container prefix and number is just a series of numbers given.. 🙂 Think again..


3) Container Owner or Lessor – This is the entity that owns or operates the container.. This could be a shipping line, like in this example (Hapag Lloyd) or a container leasing company such as Textainer who’s business is to lease containers to shipping lines that need to increase their inventory but not their assets..


4) Max Gross – In this example – 30,480 Kgs is the maximum weight that the container can carry including its own tare weight of 2,250 Kg (as shown in 7)..

This is the weight that the SOLAS VGM Certificate must show..


5) ISO Code – As per the International Standards Organisation under their code IS06346:1995(E), each container is given a unique ISO Code in order to avoid any ambiguity in naming the container..

For example, a standard 20′ container is called Dry Van (DV), General Purpose (GP), Standard (SD), Normal, Dry Container (DC) etc etc in different countries..

As these terms are all different, these terms cannot be used in uniform systems that are used for transmission of data across ports, customs, shipping lines etc..

Therefore as a standard, the ISO code of 22G1 (in the above example) is used to denote that the container in question is a 20′ container 8’6″ high with a tare weight of 2,250 Kgs..

Feel free to download the full ISO Code list for your info and reference..


6) Classification society label for type testing – Each container is tested for its strength, cargo and seaworthiness by a classification society and this label indicates which classification society certified this box..


7) Weight of Container – This is the actual weight of an empty container and this is given by the manufacturer at the end of the manufacturing and labelling process..

This is an important weight to be considered by all ships operators and planners as this weight needs to be included when planning the ship and SHOULD NOT BE IGNORED by the planners..

Imagine mega ships which currenly carry around 24,000 TEUs.. If the tare of each TEU (2250 kgs) is ignored, the ship will have an unaccounted weight of 42,750,000 Kgs = 42,750 Tons.. That is asking for a disaster at sea..

However, this weight is also heavily contested by the trade and shipping lines in terms of whether this weight should be shown on the bill of lading or not, and whether the VGM weight should match the bill of lading weight or not..


8) Max. Payload – This is the maximum weight of the cargo that can be packed in the container and the mis-declaration of this weight by the customers has severe consequences both to life and property..

This is the weight that is shown on the bill of lading and to re-confirm, it DOES NOT INCLUDE THE TARE WEIGHT OF THE CONTAINER..

This weight is clearly shown on the door of the container and customers cannot feign ignorance that they were not aware of the capacity of the container..


9) Cube – This is the maximum volume in cubic capacity that can be packed into the container.. Unlike weight, it is not possible to over pack the container by volume as it will be quite evident..

While (unlike mis-declaration of weight) mis-declaration of volume may not have any physical consequence, mis-declaration of volume on a bill of lading could have some financial consequences for the buyer or seller especially if the cargo is sold by volume..


10) CSC, ACEP & Other Certifications – Every container should have a valid safety approval plate called CSC (Container Safety Convention) plate in order for it to be used in international trade.. This is in accordance with the provisions of the International Convention on Safe Containers of 1972..

The role of this CSC plate is to confirm that the container has been inspected and found to be in a condition suitable for transportation on board the ship..

This plate has all the details of the Owners, Technical Data, and ACEP information.. ACEP being short for, Approved Continuous Examination Programme.. In short, every 30 months a container must be turned into a Container Depot for examination..

The CSC plate also shows the gross weight as can be seen in an example below..

image for CSC plate

Using above plate as an example, if a container has been loaded more than the allowed weight – in this case 32,500 kgs including the tare weight of the container, the container will be considered as OVER WEIGHT..


Other markings 

Other than above-mentioned markings, containers also have other markings such as

  1. The full container number
    • On the roof of the container – for the benefit of crane operators during loading/unloading operations
    • high cube containerInside the container close to the door – for the benefit of the packing people/surveyors etc
    • On the front of the container – for the benefit of transporters, government authorities etc during transportation as it is normal to transport the container with the doors facing the inside of the truck for security purposes..
  2. Indicators for forklift pockets for the benefit for forklift operators
  3. Caution stickers on 40’/45′ High Cube containers indicating that it is a high container

So the next time you see these markings on a container, you know what it means, what it does and make sure that you follow it for the safety of everyone in the chain..


Article republished after some content updates

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Hariesh Manaadiar
Hariesh Manaadiar
I am Hariesh Manaadiar, the Founder of Shipping and Freight Resource.. I have been in the dynamic shipping and freight industry for over three decades and have worked in several sectors.. I share my experiences and knowledge of the industry through this blog for those looking for help in the industry.. Stay subscribed for more free useful content about shipping, freight, maritime, logistics, supply chain and trade..


  1. Hello I have a question about the BIC Code.
    It would be so helpful if you help me.

    In this part,

    Equipment category – 1 letter (in above example, U denoting a freight container.. Other categories being J for detachable container-related equipment (such as Genset) and Z for trailers and chassis)..

    I heard that U stands for Union but I couldn’t find what J and Z stands for.

    I really need to figure it out. Again It would be so helpful if you give me the answer. Thank you for this such a good article and have a good day!!

  2. Hello and thank you. With regards to subject matter, I would like to know if you can help me to find what the meaning and differences are for the IC and IT marks within the UIC regulation. I am not able to find it even within the UIC regulations. Thank a lot in advance.

  3. No. 1 full container number – 3rd point…” on the back of the container” ..i think it should be “on the front of the container” as the back of the container is the door where it is placed facing the inside of the truck for security purposes.


  4. Hello, Hariesh. I want to ask You about CSC plate. How can I check that the container was inspected if the plate has Date Manufactured only?

    • Hello. In case the container unit is other than a tankcontainer, the dataplate has to have a decal with date of last CSC inspection. CSC inspections have to be performed every 2.5 years, for structure integrity. Now, if the unit is a tankcontainer, dataplate has to be stamped with date of last inspection (which includes -among other subjects- CSC and frequency is the same -2.5 years). In both cases, decal and stamping are supported by a certificate.

  5. Another top-notch article Hariesh! Thanks a lot – not only for sharing but for compiling all the info!

  6. One marking which has not been mentioned in respect of high cube containers is that besides the sticker stating it is 9’6″ high, there is the yellow and black chevron on each top corner of the container. This sticks out like a sore thumb so no one can say that they were not aware that the container is considered as over height when it hits a bridge!

  7. As always, a very valuable piece of dialogue. Thank you so very much, as I have been educated in something new today.
    Love your emails.

  8. Forgot to tell you also those codes are only marked on the sides of the containers only to be visbile when stacked on rails from each side.

    • Hi

      Those markings are for the railroads use, UIC (Union Internationale des Chemins de Fer). An organization primarily of European railroad that establishes standards for container transport on member railroads.

      ic/80 standes for Deutsche Bahn / German Railways
      ic/81 standes for Österreichische Bundesbahnen / Austrian Federal Railways.

      if you need the full codes email me.


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