Container Types and Dimensions: Standard, High Cube, Reefer, Open Top, Flat Rack and Tank
Because containers are standardized to ISO specifications, dimensions are predictable: as approximate values, a 20' standard holds ~33 m³ and ~11 Euro pallets on the floor, a 40' standard holds ~67 m³ and ~25 Euro pallets, while a 40' High Cube has the same base but, with extra height (~2.70 m), carries ~76 m³. For heat-sensitive cargo the Reefer, for out-of-gauge/project cargo the Open Top and Flat Rack, and for bulk liquid the Tank container come into play.
Because containers are standardized to ISO specifications in sea freight, their dimensions and capacities are largely predictable. This guide compares the approximate internal dimensions, volume, maximum payload and pallet figures of standard dry cargo (Dry / DC) 20', 40' and 40' High Cube containers, then explains which cargo the special types such as Reefer, Open Top, Flat Rack and Tank are used for. All values are approximate / ISO standard and may vary by container type and manufacturer.
Why Are Containers Standard? (ISO)
Containers are standardized in terms of their external dimensions and corner casting fittings according to the ISO (International Organization for Standardization) series of rules. Thanks to this standardization, ships, cranes, port terminals, trains and truck equipment worldwide fit the same transport unit; cargo can be transferred between different modes of transport (intermodal) within a single container.
Since the external dimensions are standard (the 20' and 40' length classes), the internal dimensions also remain predictable within a narrow range. The values given in this guide are approximate / ISO standard references; they may vary at the centimeter level according to wall thickness, manufacturer and container type. For this reason, each value is not an upper-limit guarantee but an approximate starting point for planning.
Standard Dry Cargo: 20' vs 40' vs 40' HC
The 20' standard dry cargo (Dry / DC) container has, as an approximate / ISO standard, internal dimensions of ~5.90 × 2.35 × 2.39 m, an internal volume of ~33 m³ and a maximum payload of ~28,000 kg. A single row on the floor accommodates approximately ~11 Euro pallets (120×80) or ~10 industrial pallets (120×100). Because of its high maximum payload capacity, the 20' is a practical unit for heavy but low-volume cargo.
The 40' standard (DC) container offers approximately ~12.03 × 2.35 × 2.39 m internal dimensions, ~67 m³ internal volume and ~26,500 kg maximum payload; it carries ~25 Euro pallets or ~21 industrial pallets on the floor. Although its internal length and volume are roughly double those of the 20', its maximum payload is somewhat lower — this is a consequence related to the weight and equipment limits of transport units, so it is ideal for voluminous cargo.
The base of the 40' High Cube (HC) container is the same as the 40' standard (~12.03 × 2.35 m); the only difference is the height: the internal height is approximately ~2.70 m, more than the standard container's ~2.39 m. This extra height raises the internal volume to ~76 m³. The pallet count on the floor is the same as the 40' standard (~25 Euro pallets); however, the additional height provides an advantage for light and voluminous cargo by allowing double-row stacking or taller individual loads.
Reefer (Refrigerated) Container
The Reefer (refrigerated; RF, and RH for the 40' HC reefer version) is a container type that provides temperature-controlled transport with an integrated refrigeration unit. The typical operating range is approximately -25 °C to +25 °C. It is used for heat-sensitive cargo such as food, pharmaceuticals (products within the scope of GDP — Good Distribution Practice), flowers and chemicals.
Due to the refrigeration unit and the insulation layer, the internal volume and pallet capacity of a Reefer are somewhat reduced compared to a dry cargo container of equivalent size; the values are approximate / ISO standard and vary by type. Reefer containers require a power connection (plug) to feed the refrigeration unit on the ship and at the terminal; this is an operational difference that must be taken into account in planning.
Open Top and Flat Rack (Out-of-Gauge / Project)
The Open Top (OT) container has a removable tarpaulin instead of a fixed roof. This allows the cargo to be loaded from above with a crane when it is too tall to fit through the standard door. Typical uses are tall loads such as machinery, glass sheets and timber.
The Flat Rack (FR) container, on the other hand, is a platform without side walls, with foldable end panels. It is designed for heavy, wide and out-of-gauge project cargo: loads such as pipes, generators, vehicles, boats and machinery are transported in this type. Although the dimensions of the Open Top and Flat Rack are close to the standard frame, they vary by type; out-of-gauge dimensions may require additional measurement and approval processes.
Tank Container and Pallet Compatibility (Euro vs Industrial)
The Tank container (Tanktainer; TK) consists of a cylindrical tank placed inside an ISO steel frame. It is used for the transport of bulk cargo such as liquids, gases, chemicals and food liquids. Because it fits the standard ISO frame dimensions, it can be handled with the same ships, cranes and terminal equipment as other containers.
Pallet compatibility varies according to the pallet standard chosen. The Euro pallet (EPAL) is the European standard measuring 120×80 cm; the industrial pallet, at 120×100 cm, has a larger base and therefore fewer of them fit into the same container. For example, on a 20' floor approximately ~11 Euro pallets versus ~10 industrial pallets, and on a 40' floor ~25 Euro pallets versus ~21 industrial pallets. The final pallet count varies according to the stacking height, pallet orientation and cargo height. Forwardie helps you determine the appropriate container type based on the nature and dimensions of your cargo; with our container capacity calculator you can estimate the pallet count.
20' Container — 40' / 40' HC Container
| 20' Container | 40' / 40' HC Container |
|---|
| Internal Dimensions (L × W × H) | Approximate / ISO standard: ~5.90 × 2.35 × 2.39 m. Since the external dimensions are standard, the internal dimensions are predictable within a narrow range. | 40' standard: ~12.03 × 2.35 × 2.39 m. 40' High Cube: ~12.03 × 2.35 × 2.70 m — the base is the same, the difference is the height (2.70 m vs 2.39 m). |
| Internal Volume | Approximately ~33 m³. | 40' standard ~67 m³; 40' High Cube ~76 m³ (the extra height increases the internal volume). |
| Maximum Payload | Approximately ~28,000 kg. A decisive advantage for heavy but low-volume cargo. | 40' standard ~26,500 kg. While the internal length is nearly double, the maximum payload is somewhat lower than the 20'. |
| Euro / Industrial Pallet (Floor, Single Row) | Approximately ~11 Euro pallets (120×80) or ~10 industrial pallets (120×100). | Approximately ~25 Euro pallets or ~21 industrial pallets. The 40' HC floor count is the same as the 40' standard (~25 Euro). |
| Extra Height Difference (HC) | None — internal height ~2.39 m (standard). | 40' High Cube internal height ~2.70 m; ~31 cm of extra height compared to the standard allows double-row stacking / taller cargo. |
| Typical Use | Heavy but volume-limited cargo, small and medium consignments. | Voluminous cargo; the 40' HC especially for light and voluminous cargo (that benefits from the height). |
| When to Prefer | When the limiting factor is weight and the volume is low. | When the limiting factor is volume; the 40' HC if extra height or double-row stacking is needed. |
Step by step
- Determine the nature of the cargo: Is your cargo general dry cargo, heat-sensitive, bulk liquid, or out-of-gauge / project cargo? The nature selects the right container family: standard (DC / HC) for dry cargo, Reefer for temperature control, Tank for bulk liquid, Open Top / Flat Rack for top loading or out-of-gauge.
- Find the limiting factor: weight or volume?: For heavy but small cargo, the maximum payload is decisive (approximately 20' ~28,000 kg, 40' ~26,500 kg). For light but voluminous cargo, the internal volume (20' ~33 m³, 40' ~67 m³, 40' HC ~76 m³) is decisive.
- Decide on the height requirement: If the cargo is voluminous, check whether the standard ~2.39 m internal height is sufficient or whether the extra height of the 40' High Cube (~2.70 m) is needed for double-row stacking or tall individual loads. While the base and floor pallet count remain the same, the height advantage comes into play here.
- Draw up the pallet plan: Determine whether you will use Euro pallets (120×80) or industrial pallets (120×100). Approximate single-row floor values: 20' ~11 Euro / ~10 industrial, 40' and 40' HC ~25 Euro / ~21 industrial. Calculate the total pallet count according to the stacking height.
- Evaluate special requirements: If temperature control is needed consider the Reefer, if loading from above with a crane is needed the Open Top, for heavy / wide / out-of-gauge cargo the Flat Rack, and for liquid-gas-chemical bulk cargo the Tank container. These requirements alone can determine the type selection.
- Verify and calculate the capacity: Remember that the values are approximate / ISO standard and may vary by type. With the Forwardie container capacity calculator you can estimate the pallet count, and with Forwardie's support you can clarify the appropriate container type according to the nature and dimensions of your cargo.
Frequently Asked Questions
What are the internal dimensions and volume of 20' and 40' containers?
With approximate / ISO standard values, the 20' standard (DC) container has internal dimensions of ~5.90 × 2.35 × 2.39 m and an internal volume of ~33 m³. The 40' standard container offers ~12.03 × 2.35 × 2.39 m internal dimensions and ~67 m³ internal volume. These values may vary at the centimeter level according to manufacturer and type.
What is the difference between a 40' High Cube and a 40' standard?
Their bases are the same (~12.03 × 2.35 m); the only difference is the height. The 40' High Cube internal height is ~2.70 m, while the standard container is ~2.39 m. This extra height raises the internal volume from ~67 m³ to ~76 m³. The pallet count on the floor stays the same (~25 Euro pallets), but the additional height allows double-row stacking or taller loads.
How many pallets fit in a container?
With approximate values, as a single row on the floor: a 20' container holds ~11 Euro pallets (120×80) or ~10 industrial pallets (120×100); a 40' and 40' HC container holds ~25 Euro pallets or ~21 industrial pallets. The total number can increase according to the stacking height and pallet orientation. With the Forwardie container capacity calculator you can estimate the pallet count.
What is a Reefer container used for?
The Reefer (refrigerated; RF / RH for the 40' HC reefer) provides temperature-controlled transport with an integrated refrigeration unit; the typical range is approximately -25 °C to +25 °C. It is used for heat-sensitive cargo such as food, pharmaceuticals (GDP), flowers and chemicals. Due to the refrigeration unit and insulation, the internal volume and pallet capacity are somewhat reduced compared to an equivalent dry cargo container.
What is the difference between Open Top and Flat Rack?
The Open Top (OT) container has a removable tarpaulin instead of a fixed roof; tall loads that do not fit through the standard door (machinery, glass sheets, timber) are loaded from above with a crane. The Flat Rack (FR), on the other hand, is a platform without side walls, with foldable end panels; it is used for heavy, wide and out-of-gauge project cargo (pipes, generators, vehicles, boats, machinery).
What is a Tank container and what cargo is it suitable for?
The Tank container (Tanktainer; TK) is a cylindrical tank placed inside an ISO steel frame. It is used for the transport of bulk cargo such as liquids, gases, chemicals and food liquids. Because it fits the standard ISO frame dimensions, it can be handled with the same ships, cranes and terminal equipment as other containers.
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