20 Types of Shipping Containers: Designs, Dimensions and Uses Explained

The standardised steel box reshaped global maritime trade more than any 20th-century trade agreement could.

Before containerisation became a thing, ships spent a lot of time at ports since cargo was loaded piece by piece, exposed to natural elements, resulting in damage and delays. 

But today, a single ship can carry more than 24,000 TEUs, thanks to standardised containers which can be handled by all port cranes, trucks and rail cars.

A shipping container is not just a simple rectangular steel box that most would imagine it to be. They are sophisticated cargo boxes designed to carry different types of cargo.

Some can maintain a temperature of −25°C throughout the journey, while some have their own ventilation systems for live animals, and there are those which must be filled to atleast 80% capacity.

If you select the wrong container type for your cargo, simply because of a lack of knowledge, or cost issues or non-availability, you would be risking cargo damage, violations and ultimately shipment detainment at ports.

This article covers all 20 container types in active maritime use, with standard dimensions, ISO specifications, and the cargo categories each is designed to handle.

What Is a Shipping Container?

In maritime, a shipping container is defined as a ‘standardised intermodal freight unit designed to transfer between ships, trucks, and rail without repackaging its contents’.

The governing standard for shipping containers is ISO 668, which was first published in 1968.

It lays down external dimensions, maximum gross mass, and structural requirements for Series 1 freight containers.

The basic unit of measurement is the Twenty-foot Equivalent Unit (TEU). A standard 20ft container equals 1 TEU; a 40ft container equals 2 TEUs.

 The world’s container fleet presently stands at approximately 50 million TEUs, and 90% of all non-bulk sea freight moves in containers.

ISO 830 further classifies containers by type code, a letter designation that describes a structural category. These codes appear on each container’s CSC (Convention for Safe Containers) plate and are used by carriers, port operators, and customs authorities worldwide.

Shipping Container Types at a Glance

Serial No	Type	Standard Sizes	Primary Use	Key Feature
1	Dry Storage (GP)	20ft, 40ft	General cargo	Fully enclosed, weatherproof
2	High Cube	40ft, 45ft	Voluminous dry cargo	30cm taller than standard
3	Flat Rack	20ft, 40ft	Oversized/heavy cargo	Collapsible end walls
4	Open Top	20ft, 40ft	Crane-loaded cargo	Removable tarpaulin roof
5	Open Side	20ft, 40ft	Long/palletised cargo	Full-length side doors
6	Double Door (Tunnel)	20ft, 40ft	Drive-through loading	Doors on both ends
7	Refrigerated (Reefer)	20ft, 40ft	Perishables	Active cooling, needs shore power
8	Insulated / Thermal	20ft, 40ft	Temperature-sensitive cargo	No external power required
9	Tank (ISO Tank)	20ft	Liquids and gases	Cylindrical tank in ISO frame
10	Platform / Flat Bed	20ft, 40ft	Extreme oversized cargo	No walls or roof
11	Half-Height	20ft	Dense bulk cargo	~50% reduced internal height
12	Car Carrier	20ft, 40ft	Vehicles	Internal collapsible racking
13	Dangerous Goods	10ft, 20ft, 40ft	Hazardous materials	IMDG Code-compliant construction
14	Intermediate Bulk (IBC)	Varies	Semi-bulk liquids/solids	1,000–3,000 litre capacity
15	Swap Body	Various	European rail/road intermodal	Non-stackable, folding legs
16	Ventilated	20ft, 40ft	Respiring agricultural cargo	Passive/active air circulation
17	Bulk (Bulktainer)	20ft	Loose dry bulk materials	Top-loading hatches, discharge doors
18	Offshore / DNV	10ft, 20ft	Oil and gas offshore ops	DNV 2.7-1 certified
19	Livestock	20ft, 40ft	Live animals	Ventilation, feeding/watering systems
20	Flexi-tank	20ft (liner)	Non-hazardous bulk liquids	Flexible bladder inside dry container

1. Dry Storage Container (General Purpose)

The dry storage container, or general purpose (GP)  container, accounts for approximately 75% of the world’s intermodal fleet. 

It is a fully enclosed, weatherproof steel box having double-leaf doors at one end, a corrugated steel roof, and a hardwood-planked floor to accommodate standard ISO lashing rings.

Standard dimensions and capacity:
• 20ft: 5.9m (L) × 2.35m (W) × 2.39m (H) | Internal volume: 33.2 m³ | Max payload: ~28,200 kg
• 40ft: 12.03m (L) × 2.4m (W) × 2.39m (H) | Internal volume: 67.7 m³ | Max payload: ~26,700 kg

They are made of Cor-Ten weathering steel, which forms a stable oxide layer that prevents corrosion without painting. 

ISO type code: G. Used for electronics, clothing, packaged food, furniture, machinery parts, and any dry cargo dimensionally compatible with the end door opening (2.33m H × 2.28m W on a 20ft unit).

2. High Cube Container

High cube containers are the same as standard dry containers but stand 30cm taller, with an internal height of 2.7m versus the standard 2.39m. 

That single dimension change offers 13% more usable volume.

Standard dimensions:
• 40ft HC: 12.03m (L) × 2.35m (W) × 2.7m (H) | Volume: ~76.4 m³ | Max payload: ~26,460 kg
• 45ft HC: 13.56m (L) × 2.35m (W) × 2.7m (H) | Volume: ~86 m³

High cube containers are ideal for lightweight but voluminous cargo such as e-commerce goods, furniture, mattresses, and bagged products.

The 45ft variant is common in European and US domestic rail intermodal but is not accepted at all deep-sea ports; hence, routing must be confirmed before booking.

3. Flat Rack Container

These containers have a steel floor and two collapsible end walls, but are devoid of a roof and side walls. 

When their end walls are folded flat, several units can be stacked horizontally, which decreases the cost of moving empty equipment.

Specifications:
• 20ft: Max payload ~40 metric tons | Floor width: ~2.23m internal
• 40ft: Max payload ~45 metric tons | Floor width: ~2.12m internal

The absence of side walls allows the cargo to extend beyond the container width; classified as an out-of-gauge (OOG) shipment, which requires special stowage planning on a ship.

Flat rack containers carry heavy industrial machinery, transformers, large-diameter steel pipe, tracked vehicles, and pre-fabricated structural sections. 

Cargo is secured with chains and turnbuckles through lashing rings on the floor rails and end walls.

4. Open Top Container

These containers have a tarpaulin for a roof, supported by steel bow members, both of which are removable.

This structure means that cargo can be lowered vertically from above by crane or overhead gantry, something which is not possible with a standard end-door container.

Available sizes: 20ft and 40ft standard; 40ft high cube open top variant also available.

They have internal lashing rings on all four walls at multiple heights. 

These containers are best to transport steel coils, marble slabs, plate glass, tall industrial machinery, and any cargo exceeding the standard door height of 2.28m.

Tarpaulin covers are secured with tension rods and must meet individual carrier specifications.

Damaged or improperly secured tarpaulins often lead to cargo claims on bulk mineral shipments.

5. Open Side Storage Container

Open side containers have full-length doors along one or both long sides of the container rather than only at the end. 

Fully open, the entire side of a 40ft unit provides 12 metres of access, far wider than the 2.3m-wide end door of a standard container.

Available sizes: 20ft and 40ft; high cube variant available.

This type of shipping container handles cargo that is too long to be go through an end door, like timber, aluminium extrusions, steel bars, and palletised goods that require forklift access from the side.

 Many open-side containers retain their end doors as well, providing 3-directional access. The side door uses the same weathertight seals and locking bars as standard end doors.

6. Double Door Container (Tunnel Container)

Double-door containers or tunnel containers feature two full sets of doors, one at each end of the box. 

Both door sets have the same weathertight seals and ISO locking mechanisms as a standard end configuration.

Available sizes: 20ft and 40ft.

These containers enable drive-through loading using a forklift that enters from one end, deposits cargo, and exits from the other without reversing. This reduces cargo loading and unloading times.. 

Common cargoes include steel bars, long pipes, and general packaged goods, where throughput speed is a priority. 

Despite appearing as two separate container types in older references, tunnel containers and double door containers are the same.

7. Refrigerated Container (Reefer)

Reefer containers feature a mechanical compressor refrigeration system mounted at one end.

Unlike insulated containers, they require a continuous external power supply from the hip’s reefer sockets, a genset, or shore power to maintain their temperature.

Temperature range: −25°C to +25°C on standard units; specialist pharmaceutical reefers reach −60°C.
Dimensions: 20ft and 40ft; also available as 40ft high cube.

Their Internal walls, floor, and ceiling are insulated with polyurethane foam. Airflow circulates under a T-bar aluminium floor to maintain even temperature distribution throughout the load. 

Reefer carries meat, fish, dairy, pharmaceuticals, flowers, and fresh produce.

Controlled Atmosphere (CA) variant: Some reefer containers also regulate gas composition, reducing oxygen levels and elevating CO₂ and nitrogen to slow the natural respiration of living produce. 

Maersk and Hapag-Lloyd both operate dedicated CA reefer fleets for banana, avocado, and apple exports, where gas management can extend shelf life by up to 2 weeks beyond standard refrigeration alone.

8. Insulated / Thermal Container

Insulated containers, as the name suggests, feature an insulated wall construction and minimal air exchange. They work on a similar principle to a thermos flask and require no active refrigeration unit or external power connection.

They are designed for cargo that must stay within a temperature band, not necessarily a cold one. 

Organs and biological materials operating under tightly specified thermal windows, certain industrial chemicals, and food products are carried in insulated containers.

The absence of a power requirement makes insulated containers cheaper to operate and simpler to position on vessels.

They cannot sustain low temperatures over a long voyage and are not a substitute for reefer containers used for frozen or chilled cargo.

9. Tank Container (ISO Tank)

ISO tank containers have a cylindrical tank usually made of stainless steel or an anti-corrosive alloy.

It is mounted within a standard 20ft ISO frame. The tank is insulated and, depending on its service classification, may include heating coils for viscous products.

Tank containers must be loaded between 80% and 95% of their capacity. Below 80%, a liquid surge creates dynamic forces that stress the tank mountings and can contribute to vessel instability. Above 95%, thermal expansion of contents can pressurise the tank beyond its design limits.

Max payload: ~26,000 kg. ISO type code: T.

Tank containers are available in food-grade (fruit juices, edible oils, wine), chemical, gas, and cryogenic variants, each requiring specific materials certification and cleaning protocols. 

A stainless steel food-grade tank cannot be used for chemical service without recertification, and vice versa.

10. Platform / Flat Bed Container

Platform containers consist entirely of a steel floor plate on ISO corner castings. They have no end walls, no side walls and no roof, so cargo can overhang in every direction without obstruction.

Platform containers are useful for truly irregular or extreme project cargo that cannot be accommodated even on a flat rack, such as power transformers, industrial reactor vessels, pre-fabricated bridge sections, and oversized structural steel modules. 

The corner castings are fully ISO-compliant, allowing platform containers to be handled by standard ship cranes and secured in normal cell guides within the vessel’s cargo hold. ISO type code: P.

11. Half-Height Container

They stand approximately 1.3m internally, which is half the height of a standard 20ft container. 

They are built of heavy-gauge steel and compensate for reduced cubic capacity with a significantly lower centre of gravity, which allows safe handling of very dense materials that would breach the maximum gross weight of a full-height container long before filling it.

They are mainly used to ship coal, stone, iron ore, and other dense minerals.

The low-profile open top design enables loading with excavator buckets and mine-side conveyor systems. 

Since they are heavy and specialised, half-height containers operate in dedicated loops between mine loading points and bulk terminal discharge facilities.

12. Car Carrier Container

Car carrier containers have internal racking, which is collapsible and holds one or more vehicles in a fixed position without ropes or wheel contact with external surfaces.

The racking absorbs vibration from both road and sea transit without transmitting stress to the vehicle.

These containers are distinct from Roll-on/Roll-off (RoRo) shipping, where vehicles are driven directly onto dedicated vessel decks.

 Car carrier containers are used when the consignment is too small for a RoRo vessel booking, when the destination lacks RoRo facilities, or when the vehicles require enclosed protection during transit. 

Some 40ft designs accommodate two cars per container on a two-level rack system.

13. Dangerous Goods Container

Dangerous goods containers are constructed and certified to meet the requirements of the International Maritime Dangerous Goods (IMDG) Code, the mandatory international standard governing all hazardous cargo at sea.

Available sizes: 10ft, 20ft, 40ft.

Depending on the IMDG hazard class of the cargo, these containers may incorporate mechanical ventilation systems (Class 2 gases, Class 3 flammables), reinforced spill containment liners (Class 8 corrosives), anti-static coatings (Class 4 flammables), or temperature-monitoring equipment. 

All dangerous goods containers must carry the correct UN hazard class placards and are subject to specific stowage positions on the vessel under SOLAS Chapter VII. 

Shipping IMDG-classified cargo in a standard general-purpose container is both a regulatory violation and a documented cause of vessel fires and explosions.

14. Intermediate Bulk Container (IBC)

Intermediate Bulk Containers handle smaller quantities of liquid or granular materials, typically between 1,000 and 3,000 litres, that are too large for standard drums but do not justify a full ISO tank booking.

The two main formats are rigid IBCs (a plastic or stainless steel tank within a steel grid pallet frame, commonly called an IBC tote) and Flexible Intermediate Bulk Containers (FIBCs), large woven polypropylene bags for dry granular materials. 

Both formats are loaded inside standard 20ft dry containers rather than handled as standalone intermodal units. 

IBCs are standard equipment in chemical, food ingredient, and pharmaceutical supply chains for products including liquid resins, industrial syrups, and concentrated detergents.

15. Swap Body Container

These are intermodal loading units built for European combined road-rail transport. They do not conform to ISO 668 dimensions but to the European standard EN 284, and they cannot be stacked; a fundamental difference from ISO containers.

They are fitted with a reinforced base structure and folding support legs, which allow the unit to be set down independently and collected by a standard curtainsider truck or flatbed without crane involvement. 

The top is typically curtained or convertible. They facilitate fast transfer between truck and rail at inland intermodal terminals across Germany, France, Belgium, the Netherlands, and Italy, but are not designed for deep-sea container vessel stowage.

16. Ventilated Container

Ventilated containers are structurally similar to standard dry containers but incorporate ventilation openings, including passive vents or active fan systems in the lower and upper side walls, to allow airflow through the cargo without permitting rain or sea spray ingress.

The design handles agricultural commodities that respire during transit: green coffee beans, raw cacao, natural rubber, and certain nuts. 

When these products are sealed inside a standard dry container, moisture from their own respiration condenses on the container walls and floor, causing mould, sweating, and cargo loss. 

Passive ventilated containers rely on natural convective airflow, and active ventilated variants use fans to force fresh air through the cargo on high-humidity trade routes such as West Africa to Europe.

17. Bulk Container (Bulktainer)

Bulk containers are 20ft dry containers modified to carry loose dry bulk commodities. 

The key differences from a standard container are two or three roof-mounted loading hatches and one or two bottom discharge doors or angled chutes.

Max payload: ~27,000 kg. Typical commodities include grain, malt, sugar, fertiliser, mineral powder, and plastic pellets.

The container is loaded through the roof hatches by overhead conveyor or pneumatic loading arm and discharged at the destination by gravity through the floor doors.

 The bulktainer allows dry bulk commodities to move on standard container vessels and through standard container terminals, avoiding the need for a dedicated bulk carrier or bulk terminal, which is a logistical and commercial advantage on smaller volume shipments.

18. Offshore / DNV Container

Offshore containers are certified to DNV standard 2.7-1 (Det Norske Veritas), which governs cargo containers used in offshore oil and gas operations. 

The standard sets requirements far above ISO 668, accounting for dynamic lifting loads, wave impact, and the structural fatigue of repeated crane operations over the sea.

Available sizes: 10ft, 20ft, and bespoke configurations.

Standard ISO-certified containers cannot legally be crane-lifted over water at offshore installations.

The DNV certification is a hard requirement under IMO guidelines for offshore supply operations. 

Offshore containers are typically constructed with heavier steel plates, reinforced corner castings, additional cross-members, and approved pad eyes for offshore lifting slings. 

They carry drilling tools, chemicals, equipment, and consumables between platform supply vessels and offshore production platforms.

19. Livestock Container

Livestock containers are purpose-built for transporting live animals, primarily cattle, sheep, goats, and horses on deep-sea and short-sea voyages. 

They have full-length ventilation panels along the side walls, internal pen or stall divisions, feeding troughs, drinking water systems, and drainage channels integrated into the floor structure.

The International Maritime Organisation’s guidelines under SOLAS Chapter VI and the standards of the World Organisation for Animal Health (OIE) set mandatory requirements for ventilation rates, stocking density, and feeding intervals during sea transport. 

A standard 20ft livestock container accommodates 8 to 12 head of cattle. Routes from Australia and New Zealand to the Middle East and from South America to North Africa are among the most active for containerised livestock shipments.

20. Flexi-tank

A flexi-tank is not a standalone container but a large flexible polyethylene bladder, typically food-grade or chemical-grade, with a multi-layer construction, which is installed inside a standard 20ft dry container before loading.

Its capacity ranges from 14,000 to 24,000 litres, depending on the bladder manufacturer and cargo density.

Flexi-tanks are used for non-hazardous bulk liquids: wine, fruit juices, vegetable oils, glycerine, latex, and non-IMDG liquid chemicals. 

Because the bladder is a single-use liner rather than a certified pressure vessel, flexi-tanks cannot carry IMDG-classified dangerous goods.

After discharge, the bladder is removed and disposed of, and the container returns to standard dry service without specialist cleaning. 

The system offers a lower cost of entry compared to an ISO tank booking and does not require tank container certification or dedicated equipment management.

Frequently Asked Questions

1. What is the most common type of shipping container?

The standard 20ft dry container is the most widely used type. The 40ft dry container and 40ft high cube are equally dominant on long-haul ocean trade lanes, where volume and cargo density favour the larger unit.

2. What is the difference between a reefer container and an insulated container?

A reefer container has a built-in refrigeration system and requires external power to actively maintain a set temperature, typically between −25°C and +25°C. 

An insulated container maintains temperature passively through wall construction, requires no power, and cannot sustain precise low temperatures across a long voyage. 

3. What does TEU mean in shipping?

TEU stands for Twenty-foot Equivalent Unit; the standard measurement of container capacity on vessels and at terminals. 

A 20ft container equals 1 TEU; a 40ft container equals 2 TEUs. The world’s largest container vessels now exceed 24,000 TEU capacity.

4. What is a High Cube container, and when should you use one?

A High Cube container provides 30cm more internal height than a standard container, yielding approximately 13% more volume within the same deck footprint.

It is the right choice for lightweight, bulky cargo where cubic space rather than weight is the limiting factor. Not all ports and terminals accept 45ft high cube containers, so routing should be confirmed before booking.

5. What are ISO container type codes?

ISO type codes, defined under ISO 830, identify a container’s structural category using a letter designation. Common codes include G (general purpose dry), R (refrigerated), T (tank), U (open top), and P (platform/flat rack). These codes appear on the CSC plate and are referenced in shipping documentation, cargo manifests, and vessel stow plans.

6. How do I choose the right container type for my cargo?

Start with the cargo category: dry, liquid, temperature-sensitive, or oversized. Then determine size requirements based on weight and volume, and consider a high cube if volume is the constraint. 

Check for any specialist requirements: hazardous goods classification under IMDG, precise temperature control, structural access needs for top or side loading, or offshore certification. 

Finally, confirm the selected container type is accepted at both the port of loading and the destination port before completing the booking.

Conclusion

Selecting the right container type for your cargo is important as a wrong decision could result in cargo loss, or damage, non-compliance with regulations, detainment of shipment at port and increased costs.

The 20 types covered in this article represent the full working range of containers in active maritime service. 

Each exists because a specific cargo requirement could not be met by the standard steel box, whether that requirement is temperature, gas control, structural access, hazardous certification, animal welfare compliance, or the absence of a rigid wall. 

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