Maritime shipping containers have been around us for ages. But still many of us don’t know much about shipping containers. They are large rectangular boxes that are used to carry different categories of goods from one place to another. You have seen them on rolling trucks, long hauling trains, and huge vessels carrying a huge number of shipping boxes at once.

The standardization of shipping containers started sometime after a few decades since the invention of cargo units. This was led by the International Organization for Standardization (ISO). The standardization helped in increasing efficiency and economies of scale when it comes to storage and transportation of cargo. In today’s date, almost everything can be transported inside a shipping container, from food grains, automobiles, to even hazardous materials like chemicals, etc.

History and evolution of shipping containers

The basic question that arises in everyone’s mind when you think about shipping containers is – how many types of shipping containers are there? What are the dimensions of a 40 ft cargo container? Who invented the shipping container? What was before shipping containers? When did shipping containers become standardized? And lots more. But do not worry as here all your questions will have all-sufficient and valid answers. Let’s know all about shipping containers by diving in.

How goods were shipped when there were no shipping containers?

Before the invention of the freight container, the cargo was handled manually as break-bulk cargo. The goods were stored at port warehouses until a boat or any other means of transport were available. When an empty vessel would arrive, then the cargo would be transported from the warehouse to the side of the docked ship. Since there were no steel shipping containers, the cargo was loaded into bales, crates, sacks, and barrels. Only after that were they loaded onto the ship by hand.

The breakbulk cargo was an extremely labor-intensive process. The transferring of cargo from shipping vessels to trains or trucks was very slow and acted as blockers, thus causing delays.

How did the idea of shipping goods in containers come up?

Malcolm McLean owned the largest trucking company in the 1930s. During that time, the cargo was loaded and unloaded from trucks and transferred from ships via odd-sized wooden cases. He contemplated the time and resources that were wasted due to the inadequacy of this method.

After this realization, he started experimenting with more effective ways to ease the handling and transportation process. Finally, he came up which we now refer to as a metal shipping container.

How was its invention a turning point in the logistic and shipping industry?

Cargo containers completely revolutionized international trade in numerous ways-

  • Goods were transported in a safe and secure manner. There were minimal reports of cargo damage and it also reduced pilfering.
  • This modernized approach was time-saving as well as cost-effective, thus reducing the expenses of the world economy.
  • There were massive reductions in labor charges as intermodal containers reduced the manpower needed to load and unload the cargo. Machines substituted machines, and there was better infrastructure created for accommodating larger shipping vessels.

All in all, this invention was a blissful influence on the world economy and it facilitated globalization as well.

How large is the present market of shipping containers?

The cargo containers market is anticipated to record a growth rate of 4.3% during the course of 2021-2026. The market is expected to be driven by maritime trade along with the complete digitization of the shipping container industry.

As of now 20ft and 40ft shipping containers are the most commonly preferred shipping box sizes of the year 2021. Other common shipping container dimensions are 8ft, 10ft, 48ft, 53ft, etc. They are widely used for the transportation of a variety of goods like food, automotive components, pharmaceuticals, and so on.

What do shipping containers carry?

Almost everything we use on a day-to-day basis has been stored and transported inside a cargo unit at some point.  A unit can carry almost anything, over a variety of cargo categories:

  • Non-perishable cargo, like, manufactured goods, dry cargo, furniture, etc.
  • Perishable cargo, or goods that require specific temperature control like frozen goods, agricultural products, dairy products, seafood, etc.
  • Oversized cargo like building materials, automobiles, machinery, lumber, construction equipment, etc.
  • Hazardous or non-hazardous materials in bulk, like chemicals, liquids, oils, etc.
  • Minerals like copper, coal, etc. that are extremely necessary for generating electricity for our homes are also transported in cargo vessels.

Structure of a shipping container 

A shipping container is made of various structural components that work together to form a sturdy structure that is suitable to carry all kinds of cargo. The most integral elements of a steel shipping container are:

Roof: The roof is constructed from Cor-Ten steel that is extremely rigid and provides strength. It is a special steel blend that is water-resistant and prevents cargo damage.

Walls: The boxes are also made from 14 gauge Cor-Ten steel and are corrugated. The walls are connected into a top rail which acts as a connection between the roof and floor of the cargo unit.

Floor: Shipping container floors are made from steel and plywood. There are cross-members of steel that are spread across the width of the unit.

Doors- There are usually two doors that can swing upon towards one end of the cargo container. They have lock-rods that are the same in height as the unit. Door levers are used to open and close the container doors. There is certain information that is printed on the top of the container doors. This includes container number, ISO code, tare, and net weight, other important certifications.

Corner posts: There are four corner posts that hold the weight of the entire shipping unit while stacking. They also have corner castings that are helpful in locking the units on ships.

Shipping containers vs storage containers: The difference

Maritime containers are standard-sized boxes that are used to store and transport cargo from one location to another. They are corrugated steel boxes and are extremely sturdy as they carry large loads of cargo. They come in many types and dimensions, but the most commonly used dimensions are 20 and 40ft units.

The construction of storage containers, on the other hand, is not as specific as shipping containers. They can be built from lower-grade steel and any dimensions as per requirements. However, most cargo units can be used as storage containers also.

Container Types- on the basis of cargo compatibility

To suit almost all types of goods, a different range of steel shipping containers has been designed till now.

Dry Van

Dry Van is one of the most versatile container types. It can carry almost all types of dry freight. It is suitable both for transportation and storage of cargo. Due to their capacity of carrying a wide range of dry products, the demand is always on the surge. Their design and structure promise full security to the cargo residing inside. Dry van cargo units are highly affordable, utterly flexible, and are a secure means of transporting dry cargo all over the world.

Pallet Wide

Pallet Wide is another very common container type that is much in demand in Europe. In Europe, a certain type of pallet of dimension (1200x800x144) mm is there. To accommodate these euro pallets inside a box, a special type of unit came into existence, Pallet Wide Container. It optimizes the carriage of euro-pallets while only being minimally wider than the Dry Van Container. The construction of it is different from others as it has a four-way wood pallet nailed with iron nails in a uniform pattern. When compared to general standard boxes, they can carry three to six extra pallets, which is the biggest advantage it serves. It is ideal for transporting goods like raw materials, machinery, tools, etc.

Double door

Unlike other freight units, double door containers are slightly different in design. Where a general box has a door on one side, a double door has a door on both sides. That is why it bears the name double door and tunnel-tainer. It has 14 gauge welding that adorns the main structure. These boxes are perfect for the transportation of large, oversized cargoes. The two doors allow for easier access during the loading and unloading of cargoes. Also, you can easily stow goods in them.

Side door

Just like double door ones, side door containers are also famous for their unique design. They have bi-fold doors that make them unique. It can open both partially and fully depending upon the space required for loading and unloading. When you open the door fully, one side of the unit gets completely opened.

The concept behind designing such boxes was to accommodate large size cargo inside a box easily. Due to its design and structural integrity, they also find their application as a storage unit. Moreover, side doors are also the best option for building houses. A side door container provides the maximum holding capacity which makes them suitable for the building of homes, garages, swimming pools, stores, malls, etc.

Open Top

Open top containers are yet another container type famous for their unique design and structure. As the name suggests, an open-top box does not have any fixed steel ceiling. One can always open or fix the top part using a tarpaulin instead of a solid roof. It has a movable top rail and a swinging header facilitating convenient loading operations.

This container is for the cargo type that is heavier enough and you can only load from the top using cranes or forklifts. The box is in wide use for the transportation of oversized goods that protrude beyond the standard height.

Hard Top Open Top

Hard top open top containers are mostly in use for the transportation of heavy and bulky cargoes that needs cranes for loading. In most of the contexts, they are similar to open top, with the only difference being they have a removable steel roof instead of a tarpaulin. You can either remove or fix the removable steel roof depending upon the need. The forklift conveniently lifts the roof weighing approx. 450kg. The lashing rings installed in the lower and upper side rails bound the goods.

Flat Racks

Flat rack containers facilitate the transport of heavy and oversized cargoes that cannot fit inside a closed body. There are certain goods like automobiles, trucks, planes, army tanks, jets, that one cannot accommodate inside a closed box and hence flat rack containers come into the scene.

It has just two end walls on its shorter side which you can either fix or collapse. It does not comprise a roof. Heavy tarpaulin sheets cover the shipping unit from all sides in order to protect the cargo while transportation. In order to secure the goods, the shippers use the covers, pad eyes, lashing rings, and clamp locks. The flat rack also acts as a platform container when one removes both of its walls. It comes in two different dimensions- a 20ft and 40ft flat rack.


A platform container is a simple floor arrangement that does not comprise any end or sidewalls. It can accommodate cargo exceeding the dimensions of the box. It has a reinforced base with no walls on any of its sides, no roof, and just a floor. The lashing bars secure the cargo on the outside profile of the bottom rail. The flooring is either of wood or steel and bears a very high loading capacity.

Specific dimensions and capacity of platform containers may vary depending on the container manufacturer, container’s age, and its owner. They can especially ship irregular-sized cargo that any other container cannot accommodate and is suitable for extremely heavy-duty. As mentioned above, a collapsible flat rack container is similar to a platform container.

Insulated Containers

As the name itself speaks that insulated containers are the ones that have a certain type of insulation done on their body. It comes with temperature-controlled features that keep perishable cargo safe.  The units also prevent contamination, moisture, and sunlight from entering the cargo unit.

It is in use for the shipment of temperature-sensitive products like medicines, foods, biological goods such as organs, blood, etc. It is well insulated using insulation material, bubble glass, gas-filled pipes, and airtight doors. All of this contributes to maintaining their temperature for a long allowing goods to remain fresh for days.


Many people confuse reefers with insulated containers but both carry a slight difference. Refrigerated containers are like big-size fridges that store and transport perishable items over a long distance. Unlike insulated containers, reefers have an inbuilt refrigeration unit that enables them to maintain temperature for a long without ruining the goods. It has an electric or diesel heating or cooling unit that can retain temperature from-35◦ C to +30◦C.


Bulker is a type that is in wide use in the shipment of dry bulk cargoes like coffee beans, grains, fertilizers, cement, sand granules, etc. It has an opening on its top through which the loaders load goods. While the unloading takes place from hatches built on its lower doors or front panels. It has a built-in ladder that takes you to the top to examine the loading process. Bulkers are very useful for dry bulk cargoes because they specifically facilitate their shipment.


Tank Containers are one of the most sought-after container types. This is because they are solely capable of carrying certain goods that other boxes fail to ship. Liquid and gaseous goods to hazardous chemicals stuff, it carries all fluid and gaseous content swiftly. Being made from stainless steel, it has a layer of insulation and an external protective layer of Polyurethane or Aluminum. You can load goods via a central hatch on the roof while unloading happens through a valve outlet made at the bottom of the tankers.

Container Types- On the basis of dimensions 

8ft Shipping Containers

8ft shipping containers are the smallest size containers. These are mostly in use for personal usage or small business storage like for shifting home, storing small industrial equipment, carrying camping essentials for the whole family, etc. It is extremely handy for shipping smaller volumes of goods within the country or overseas. It usually comes with internal dimensions of 7ft x 6ft x 6ft.

10ft Shipping Containers

10ft ones are highly mobile that one can secure with a lock as well. Since the boxes are very small in size, they can fit any vehicle with other goods. It is ideal for industrial equipment shelters and mobile machinery storage. This sized container is not so common in shipping. It offers the internal space of 9’3ft x 7’8ft x 7’10ft.

20ft Shipping Containers

20ft shipping container is one of the most common shipping container dimensions. It offers 1169 cubic feet of space which is roughly equivalent to the storage capacity of a car garage. It has thick marine plywood flooring on the interior. Due to their dimension and sturdiness, they are in extensive use for the transportation of a large variety of goods, used as storage units, and for building purposes. All 20ft boxes have the same exterior dimension except a few like insulated boxes and reefers due to the modification done on internal walls. It offers an interior space of 19’4ft x 7’8ft x 7’10ft.

20ft high cube

20ft high cubes are one of the preferred choices when it comes to the transportation of heightened and oversized goods. These are comparatively higher than standard boxes. The internal dimension may vary slightly depending upon the type of material used during manufacturing. You can stow the heightened goods without touching the ceiling of the box. In fact, for building purposes too, these boxes come to be an advantage. People use them for making different things like a swimming pool, house, store, or café. It comes in an internal dimension of 19’4ft x 7’8ft x 8’10ft.

40ft Shipping Containers

40 ft cargo containers are one of the largest dimensions available in a standard shipping container. They have mostly commercial and industrial applications. It can accommodate a good volume of goods and is best for shipping items over long distances. Built from high-quality corrugated steel, it has the capacity to bear the load of heavy cargoes and withstand the worse climatic conditions. It offers an internal space of 39’5ft x 7’8ft x 7’10ft.

40ft high cube

The 40ft High Cube Container is similar in structure to standard boxes. But they are about 1 foot taller than regular 40ft boxes. It offers a better option for heightened goods ensuring that you can store or transport the goods protruding the height of 40ft in them. Their extra height results in 2,660 cubic feet of total storage space. It offers the internal space of dimension 39’5ft x 7’8ft x 8’10ft.

45ft high cube

The 45ft high cube containers offer huge storage space. They are very much compatible with heavy and bulky goods. These are equally compatible for building purposes due to increased height and internal dimensions. Besides, people highly prefer them for building purposes as well. They could easily ship lighter and heavier general cargo on the sea and land to utilize the maximum cubic capacity due to their flexible design. It comes with an internal space of 44’5ft x 7’11ft x 8’10ft.

48ft Shipping Containers

48ft shipping containers are the ones that in comparison to ISO containers, are 6 inches wider. It has lockable doors on one end that one can open with an easy open-door handle, and consists of a high-security lock. Their size came into existence by the shipping company APL (American President Line) in 1986. It sports an internal space of 47’5ft x 8’11ft x 8’2ft.

53ft Shipping Containers

The 53ft container dimension first saw its introduction in the United States in 1989. It provides a volume of over 4280 cubic feet. It is widely in use mainly for domestic road and rail transport. For this very reason, it is one of the favorite choices of cargotecture companies. They provide almost 50% of more internal storage space as compared to standard 40ft containers. It offers an internal space of 53ft x 9ft x 8ft.

60ft Shipping Containers

Some 20 years after the introduction of 53ft boxes, 60ft boxes came to the world. 60ft shipping containers are the largest metal containers today. It can accommodate a large volume of goods at one time. It facilitates container companies to ship almost 13% more volume of goods per box.

Standard containers vs High cube containers

  • The most prominent difference between standard and high cube containers is the height difference of approximately 1 foot. The approximate height of high cubes is 9ft 6 inches while the height of standard containers is 8ft 6 inches.
  • Another difference between the two is on the basis of weight. High cube units lie on the heavier side whereas standard boxers are lighter than them. Standard shipping boxes are a more convenient option as they are cost-effective than their high cube counterparts.

In conclusion, we can decipher that both standards, as well as high cube units, have their own benefits and shortcomings. It is up to the shipper to decide which one they want to go with, depending upon the cargo they want to transport.

Container Types – On the basis of grades


IICL is the abbreviation for “International Institute of Container Lessors”. They are one of the most stringent of all kinds of new and used shipping containers. This is a container condition that IICL put forward to certify cargo units to be in perfect working condition for the transportation and shipping of containers over long journeys.


Cargo-worthy, or CW, is a grading category of used shipping containers that are eligible for the transportation of cargo all over the world. This usually implies that the metal unit has a valid shipping container CSC certification. They are ideal for both storage and transportation purposes.

Wind and watertight

The WWT containers are a category similar to CW cargo units. They are old boxes that are not worthy of cargo shipping. People use them for storage purposes. As their name suggests, they are wind and water-resistant and are suitable for commercial and residential storage.

Container Types- On the basis of usability

Containers can be both brand new and second-hand. The condition of the container is one of the primary factors on the purchase price. Both are equally in demand because even if it is a used one, it poses equal worth in terms of functions, sturdiness, and durability.


The shippers refer to new containers as one-trip cargo units also. They are an ideal choice for anyone who is looking for a long-term investment in shipping boxes. They are sturdy, robust boxes that are durable for a minimum of 15-20 years. Since they are in excellent working condition, they are perfect for transporting medical supplies, electrical equipment, etc.

When should I buy a new box?

There isn’t a certain condition that can describe that you should buy new containers. However, one can determine by following things like

  • if aesthetic is important for you
  • when you want them for 15 to 20 years
  • if you are doubtful about used boxes


The used containers or second-hand containers are the ones that were already in use by other shippers. It can either be a month old or 10 years old. A used box doesn’t mean they are not strong or durable enough. They are often in excellent condition only with slight signs of blemishes, dents, or rust, or holes. A little evidence of wear and tear doesn’t destroy the real worth of the containers. They can still last for decades. It all depends on what grade of container you are buying.

When should I buy a used box?

Buying a used container can be a good decision if aesthetics is not so important and you want to save on your expenditure. You will find used containers cheaper than the new ones. Another thing you should keep in mind while buying a used one is- their condition. If the supplier promises you its quality, do not forget to inspect it on your own.

Container Types- On the basis of nomenclature

Shipping container

The shipping containers as the name says are vastly in use for the storage and transportation of different merchandise. They are moved from one place to another by sea, air, road, or rail. It comes in standard dimensions of 20ft and 40ft freight containers. As they are of steel, aluminum, or Corten steel they can easily carry heavier loads.

Cargo containers

Cargo container is another name that is in vogue for cargo boxes. They are in use for transferring different types of goods from one place to another by using different transportation modes. They are widely in use for storing different items as well.

Steel Shipping Containers

The shipping units get the name steel shipping containers as steel is their core metal. They are versatile and much in use for transportation of cargoes to far-off places. Being highly durable, resistant to extreme weather they can easily sail to longer distances.

Freight containers

Freight containers are the ones that loaders use for cargo shipping to distant places by using various intermodal transportation methods like the sea, air, water, road, and rail.

Metal Shipping Containers

Cargo units are widely known as metal shipping containers as they are made from different metals like aluminum, steel, or Corten steel. They can easily carry heavier loads and go farther distances without raising any issue. They can work well for longer duration like years and are sturdy and reliant.

Intermodal containers

Intermodal containers are the ones that use different modes for container transportation for moving the goods to distinct places. Many times the cargo cannot reach the destination in one go as the destined location is far from any sea-port, airport, and railway station. That is when the intermodal containers go through intermodal transportation to reach the user.

ISO containers

ISO containers are the ones that manufacturing companies make as per International Organization of Standardization (ISO) guidelines. One can transport them to national and international borders and countries without any concern via air, ship, road, and rail. 20ft and 40ft ISO containers are the ones that shippers find suitable for shipping cargo to distant places.
SOC containers

SOC containers or shipper-owned containers are in use mostly for transporting the goods. The shippers have to arrange the freight units by themselves. From loading to unloading the shipper has to take responsibility for every detail. They come in handy in places where the logistics services foothold is not strong. By buying SOC containers, shippers save themselves from huge charges of demurrage and detention.

CONEX boxes

It is another term for shipping units. They came into being during World War II to transport military cargo to the borders. At that time, they were known as transporters. Conex word came into existence from the term Container Express that was used after the Korean War. Later people started using Conex containers for transporting the cargo to one place from another.

What are the options to acquire shipping containers?

One can purchase shipping containers in two ways- buying or leasing. Both have their own pros but depend hugely on your purpose and the period for which you want them.

Buy shipping containers
Shipping containers are the greatest assets if you buy them. People generally buy them when they have a long-term need. Instead of paying rent to the carriers every time for containers, buying gives you added benefits- you own it, you control its supply, and you can plan your shipment anytime for any location. When you buy, you just have to bear a one-time cost and avail complete ownership of it. You also escape from additional demurrage and detention charges. While leasing can dig money from your pocket monthly or quarterly. Although the initial cost is higher, it proves its worth in the long run (if you want them for the long run).

Lease shipping containers

Leasing shipping is yet another good way to acquire shipping containers. There are several ways by which one can rent them- One Way Lease, Long Term Lease, Master Lease Agreement, and Short Term Lease. Like buying, leasing also has its own pros in conditions like:

  • When you need them to use as temporary storage space
  • To manage the factory storage overflows
  • In case of sporadic shipping
  • When you want them for a single trip

What are the different uses of shipping containers? 

Freight boxes are quite versatile. Though their invention was solely to fulfill shipment needs, today their application is prevalently visible in almost every field.


They are hugely in use for the shipment of different types of cargoes (large, heavy, bulky, liquid, gaseous, perishable, hazardous chemical, etc.). Every day shippers load and unload tons of goods on board to support the supply chain system to further meet the consumer demands across the world.


Besides shipment of goods, they act as perfect storage units. Due to their large size, lockable doors, and portability features, they are in vast use for storing all types of goods. Be it for industrial use, storing raw materials, manufactured goods, household equipment, or anything.

As building material

From the past few decades, these huge boxes have found their way to the construction field in making creative, quirky, and beautiful things. Modern shipping containers homes, offices, stores, malls, restaurants, garages, gyms have been in the recent trend catching the eyes of millions. Countries like the USA, Brazil, and Australia have witnessed a good number of container buildings along the lane.

Labels and markings on a shipping container

Container Number

The container number is one of the most important markings on the cargo unit. It has four alphabets and 7 numbers and is in alpha-numeric sequence. The ISO created this unique identification system under the code ISO6346:1995(E). The identification system consists of certain components like:

  • Owner Code – Should be in 3 letters
  • Equipment category – 1 letter
  • Serial number – contains only 6 numbers
  • Check digit – only 1 number

This code is unique to container owners and the owner should register them with the Bureau of International Containers (BIC) to avoid any duplication by other owners or operators.

Owner’s logo

For the identification of the owner of the box, the owner’s logo is mandatory to be placed at the door of the unit. The logo should be visible and provide a unique identity to the cargo box.

ISO code

The ISO provides a unique code to the shipping units to save the boxes any ambiguity. It avoids any issue of container naming and provides uniqueness to the units.

Weights & payload

The manufacturers provide this label after the manufacturing of cargo units is over. They put the label of the actual weightage of the empty container before shipping it to the suppliers or business people.

By maximum payload, the label conveys the optimum weight the container can bear for cargoes. The declaration of payload and weight is mandatory as it can save lives and cargo or put it at risk. If the shipper or loaders puts extra weight than needed, the freight unit will collapse, thus spilling all the merchandise and can also put lives at risk.

Approved classification society label

The approval of the society label is necessary as many societies or governing bodies are there who ensure that the box contains all the necessary labeling, is in good working condition, and has all the certificates in place. With this statuary label, the units have the label of NED or Next Examination Date so that the containers go for inspections on time.

Cube or volume

Through cube or volume label, the maximum volume a shipping unit can hold is mentioned. Any of the boxes cannot ever load the cargo if it exceeds the limit but it is necessary to mention it for the sake of any detention or extra charges. If the shippers fail to proclaim the cube or volume, they may have to pay the charges while unloading the merchandise.

Waring and operational signs

Hazardous cargo warnings, caution stickers are the ones that are additional operational signs that the shippers must check their shipping units must-have. Hazardous cargo warning when they are shipping harmful or toxic chemicals or medicines that if not handled properly can cause danger to human life.

Caution stickers are for mentioning the height of the boxes especially in the case of high cube containers. The high cubes are 1ft extra in height than standard shipping containers. That is why it is necessary to mention the sticker as there are many tunnels, bridges, roads, or others that don’t allow the movement of heavy-weight container-carrying vehicles.


According to the International Convention on Safe Containers of 1972, it is necessary for every box to have a CSC Certification plate for safe and secure international transportation of the boxes. It shows that the cargo unit is in perfect condition and fit for further transportation. The plate consists of all details relating to technical data, PES, ACEP, owner’s details, and others. For more details, read CSC plate certification for shipping containers.

Where to find the best container supplier? 

This is a very common question that shippers ask about how to rid themselves of the old containers. Most people after using boxes for several years find no application in the future and want to get rid of them. You wouldn’t want them to give away to anyone for free when you had purchased them after paying a hefty sum. To sell used containers, you can either contact shippers, freight forwarders, or just scrap dealers. To your concern whether you will get a worthy sum in return or not, we could guide you to another amazing platform- takes you through a number of buyers across the world who willingly buy second-hand containers. It’s an open marketplace that allows people from all around the globe to buy and sell containers online. The multiple negotiation facility enables you to make a deal only when you find it profitable.

Did we miss anything? 

Write to us in a comment if you would like to know anything else about containers that we might have missed. Or log in to to explore more about shipping containers and buy and sell the containers of your choice by matching with local and international buyers and sellers. We have numerous container options to choose from so choose the best by contacting us.