When selecting between different types of shipping containers, the right equipment starts with the cargo, not simply the container’s advertised size. A shipper needs to consider the cargo’s dimensions, weight, packaging, loading method, and route before deciding between a 20 ft container, 40 ft container, or another equipment type. Understanding shipping container sizes and shipping container dimensions helps shippers identify potential loading, payload, and equipment issues before the booking is confirmed. This guide explains the common container options, how their dimensions affect practical loading decisions, and what shippers should check before confirming equipment for an actual shipment.
Why Container Choice Matters Before You Book
Container selection is an operational decision that should be made before a shipment is booked, not after the cargo is ready to move. The right equipment needs to match the cargo’s type, size, weight, and loading requirements.
Three decisions usually come first: container type, container size, and container height. A standard dry container may suit general cargo, while other cargo may require specialised equipment or additional space.
Choosing unsuitable equipment can leave capacity unused, create weight or dimensional restrictions, or make loading and securing more difficult. For oversized cargo, it can also lead to OOG charges or additional handling requirements. Equipment availability on the required route can also affect the booking and may contribute to delays if the requested container is not available when needed, particularly when arranging containerised road movement.
The rest of this guide looks at the main types of shipping containers, their shipping container sizes and dimensions, and the practical checks shippers should make before confirming equipment.
Standard Dry Containers: What They Are and When to Use Them
Standard dry containers are the most widely used types of shipping containers for general cargo that does not require temperature control or specialised loading equipment. They are commonly used across sea, road, and rail movements for goods such as boxed products, bagged commodities, FMCG, textiles, auto components, suitably packaged chemicals, and other manufactured goods.
The main options include 20' and 40' standard containers, along with high-cube versions that provide additional internal height. When comparing shipping container sizes, it is important to look beyond length. Height affects the amount of cargo that can be loaded vertically, while internal volume indicates how much space is available. Payload, meanwhile, refers to the cargo weight the equipment can safely carry and may become the limiting factor before the available volume is fully used.
20-Foot Standard Container
A typical 20-foot container is approximately 6.1 m long externally, with internal length around 5.9 m. Internal width is generally around 2.35 m, while internal height is around 2.39 m. Door openings are smaller than the full internal dimensions and must be checked when cargo is being loaded through the doors. Internal volume is typically around 33 m³, while payload can vary by equipment specification and carrier.
A 20' container can make sense for denser or heavier cargo where weight becomes the main constraint, such as steel products, machinery, suitable packaged chemicals, bagged materials, or ceramics. These figures are approximate; confirm the actual 20 ft shipping container dimensions and payload before booking.
40-Foot Standard Container
A typical 40-foot standard container is approximately 12.2 m long externally, with an internal length of around 12.0 m. The internal width is generally around 2.35 m and the internal height around 2.39 m. Its internal volume is typically around 67 m³, giving substantially more loading space than a 20' container. Payload varies according to the specific equipment and carrier.
The additional volume can be useful for lighter, higher-volume cargo such as consumer goods, packaged products, garments, and plastic goods. However, a larger container does not automatically mean a lower freight cost. The actual rate depends on the shipping lane, carrier, equipment availability, and booking conditions.
How to Choose Between a 20-Foot and 40-Foot Container
The main question when choosing between a 20-foot and 40-foot container is simple: will your cargo reach its weight limit or its space limit first?
Start With Your Cargo
Before choosing a container size, check:
Total weight – Dense cargo may reach the payload limit before using all the available space.
Total volume – Light, bulky cargo may need the additional capacity of a 40-foot container.
Pallet dimensions – Check whether your pallets can be loaded efficiently within the container.
Stackability – If the cargo cannot be stacked, you may need more floor space.
Loading requirements – Door opening dimensions and access can matter for large or awkwardly packaged goods.
When to Choose a 20-Foot Container
A 20-foot container can be more suitable when:
The cargo is relatively dense or heavy.
The shipment does not require the additional volume of a 40-foot container.
You want to avoid paying for unused space.
When to Choose a 40-Foot Container
A 40-foot container may be more suitable when:
The cargo is light but takes up more space.
You are shipping larger volumes of packaged or bulky goods.
Your cargo can make effective use of the additional container capacity.
When Two 20-Foot Containers Make More Sense
Sometimes, using two 20-foot containers is more practical than one 40-foot container. This can be useful when cargo needs to be:
Delivered to different consignees
Separated by cargo type
Shipped on different schedules
Matched to the equipment available on a particular route
The goal is to choose a container that gives you enough usable capacity without paying for unnecessary space. Before confirming the shipping container size, check the actual container specifications, route restrictions, and equipment availability with your carrier.
High Cube Containers: What Changes and When to Specify One
A high cube container follows the same basic design as a standard dry container but provides extra height. It is typically about one foot taller externally, which also increases the available internal height and overall cubic capacity. This difference can matter when cargo is tall, bulky or needs more vertical clearance.
For shippers comparing types of shipping containers, a high cube can make sense when the standard internal height would leave too little usable space. It is commonly considered for tall pallets, furniture, garments, and other lightweight cargo that takes up more volume than weight. The 40HC is a common high cube format, while 20HC availability can vary by route and equipment operator.
The extra height should still be checked against the actual loading plan. Confirm the door opening, cargo dimensions, and required clearance rather than relying only on published shipping container dimensions. For inland movement, road height limits, bridge restrictions and local transport requirements may also affect whether the equipment is practical.
High cube rates and availability are not fixed across all routes. Before booking, confirm the specific equipment, sailing availability, and compatibility with the planned inland transport.
What to Check Before Matching Cargo to a Container
Once the container size is narrowed down, the cargo itself should be checked against the available shipping container dimensions. A container may have enough overall space but still be unsuitable because of the cargo's shape, weight, or loading method.
Cargo Dimensions
Measure the cargo's length, width, and height, including packaging. These measurements help confirm whether the units can enter through the container doors and fit inside without forcing an unsuitable loading arrangement.
Cargo Weight
Check the total shipment weight as well as the weight of each pallet or unit. The container's permitted payload must be considered alongside the cargo weight, rather than relying only on available volume.
Pallet and Loading Configuration
Review pallet dimensions, quantity, stackability, and loading orientation. Two shipments with similar volumes may require different containers if their pallets cannot be stacked or arranged efficiently.
Door Opening vs Internal Dimensions
Internal dimensions do not represent the actual door opening. Check the door width and height before booking, and allow space for packaging, handling, and securing equipment.
Loading and Securing Requirements
Consider whether loading requires a forklift or crane and how the cargo will be secured. Heavy machinery may also require attention to weight distribution and centre of gravity. These checks help match the cargo to the appropriate equipment before the booking is confirmed.
What are the Specialised Container Types?
Standard dry containers cover many shipments, but some cargo needs different loading access, temperature control, or support for unusual dimensions. These types of shipping containers should be considered when the cargo cannot be handled safely or efficiently in a standard unit.
Reefer Containers
Reefer containers have built-in refrigeration for cargo that needs controlled temperature conditions. They are used for perishable food, dairy, pharmaceuticals, floriculture, and certain temperature-sensitive chemicals. The required temperature depends on the cargo and equipment specification, so confirm the set point before booking. Also check reefer plug availability at both origin and destination. Reefer equipment and handling generally involve higher costs than standard dry containers.
Open Top Containers
Open top containers have a removable tarpaulin roof, allowing cargo to be loaded from above when it cannot be loaded through standard doors. They can be used for heavy machinery, large industrial components, certain steel products, and some overheight cargo. Proper securing is essential, while overheight cargo may require OOG handling and additional charges.
Flat Rack Containers
Flat racks are open-sided platforms with end walls and are used for out-of-gauge cargo such as transformers, construction machinery, large vehicles and oversized industrial equipment. These shipments need specialised lashing and securing, along with early coordination for equipment and port handling. Availability and charges can vary significantly by shipment.
Tank Containers and Flexitanks
Tank containers use an ISO frame around a tank for suitable liquid bulk cargo, including certain hazardous and non-hazardous liquids. Flexitanks are single-use liners installed inside a standard 20-foot container for suitable non-hazardous bulk liquids. Product compatibility must be confirmed before booking; not every liquid is suitable for a flexitank.
TEU Explained: Why It Appears in Container Shipping
TEU stands for Twenty-foot Equivalent Unit and is a standard measurement used to describe container capacity and shipping volume. A 20-foot container represents 1 TEU, while a 40-foot container and a 40HC represent 2 TEUs.
TEU is not a separate container type. Instead, it provides a common way to measure the capacity of vessels and terminals and to describe shipping volumes, carrier allocations, and volume commitments. For shippers, understanding TEU can make carrier schedules, capacity announcements, and shipping agreements easier to interpret. It also helps distinguish between the physical shipping container sizes being booked and the industry measurement used to describe overall container volume.
Shipping Container Dimensions: Quick Reference for Freight Planning
The table below gives a practical reference for common shipping container dimensions. These figures are approximate because dimensions and payload can vary by manufacturer, container specification, and equipment condition.
Container Type | External L × W × H | Internal L × W × H | Approx. Volume | Typical Payload |
20' Standard | 6.06 × 2.44 × 2.59 m | ~5.90 × 2.35 × 2.39 m | ~33 CBM | ~26–28 tonnes |
40' Standard | 12.19 × 2.44 × 2.59 m | ~12.03 × 2.35 × 2.39 m | ~67 CBM | ~26–28 tonnes |
40' High Cube | 12.19 × 2.44 × 2.90 m | ~12.03 × 2.35 × 2.70 m | ~76 CBM | Varies by specification |
20' High Cube | 6.06 × 2.44 × 2.90 m | ~5.90 × 2.35 × 2.70 m | ~37 CBM | Varies by specification |
For 20 ft shipping container dimensions, the internal space is smaller than the external measurements suggest, and the door opening can be smaller again. This matters when loading pallets, machinery or cargo with limited clearance. Door width and height should therefore be checked alongside internal dimensions rather than relying on the container's nominal size.
Payload is also not simply the maximum cargo weight. It depends on the container's tare weight, maximum permitted gross weight and applicable road or transport restrictions. Before booking, confirm the actual equipment specification, including dimensions, door opening, and payload, with the carrier or equipment provider.
How to Select the Right Container for Your Cargo
Once cargo dimensions, weight, and loading requirements are clear, the container selection process can be narrowed down using a simple equipment framework:
General dry cargo → Standard dry container: Suitable for most boxed, palletised, and non-temperature-sensitive freight.
Dense or heavy cargo → Consider a 20' container: Its shorter floor area can be practical when payload, rather than volume, is the main constraint.
Light, high-volume cargo → Consider 40' or 40HC: Extra internal space can be useful when the shipment fills by volume before reaching its weight limit.
Tall cargo → Consider high cube: The additional internal height provides more vertical clearance.
Temperature-sensitive cargo → Reefer: Use where the cargo requires controlled temperature conditions.
Top-loading or overheight cargo → Open top: Useful when cargo cannot be loaded through standard doors.
Out-of-gauge cargo → Flat rack: Designed for cargo that exceeds standard container dimensions.
Suitable liquid bulk cargo → Tank container or flexitank: The choice depends on the liquid, compatibility, and handling requirements.
The final selection should also account for shipping container sizes and dimensions, loading method, route, equipment availability, and carrier requirements before booking.
Conclusion
Choosing between different container types and sizes should start with the cargo, not simply the container's nominal capacity. Weight, dimensions, palletisation, loading method, route restrictions and equipment availability all affect the final choice. Checking these factors before booking helps shippers avoid unsuitable equipment, loading problems and unexpected handling requirements.
FAQs
What are the dimensions of a 20-foot shipping container?
A standard 20-foot shipping container is approximately 6.06 m × 2.44 m × 2.59 m externally and around 5.90 m × 2.35 m × 2.39 m internally. Its capacity is roughly 33 CBM, although dimensions can vary by manufacturer and container specification. Check the actual internal dimensions and door opening before loading.
What is the difference between a 20-foot and 40-foot container?
A 20-foot container provides approximately 33 CBM, while a standard 40-foot container offers around 67 CBM. A 20-foot container can be suitable for dense or heavier cargo, while a 40-foot container provides more space for lighter, higher-volume shipments. The choice also depends on cargo dimensions, weight, loading configuration, and route availability.
What is the difference between a standard and high cube container?
A high cube container is approximately one foot taller externally than a standard container, providing greater internal height and cubic capacity. The extra space can be useful for tall pallets, garments, furniture and lightweight bulky cargo. Before booking, check door dimensions, road clearance requirements and whether high cube equipment is available on the required route.
When do I need a reefer, open top or flat rack container?
A reefer is used for temperature-sensitive cargo requiring controlled conditions. An open top can suit cargo that needs to be loaded from above or exceeds standard door height. A flat rack is generally used for out-of-gauge cargo such as large machinery, transformers or industrial equipment. Specialised equipment may require additional securing, handling and charges.
When is a flat rack container required?
A flat rack container is generally required for out-of-gauge (OOG) cargo that cannot fit safely inside a standard container. It is commonly used for heavy machinery, transformers, large vehicles, construction equipment, and oversized industrial components. Because the cargo may extend beyond the container’s length, width or height, proper lashing and securing are essential. Flat rack availability, port handling requirements, and additional charges should also be confirmed with the carrier before booking.