Classification Guide

Container Types Explained

Shipping containers come in multiple standardized formats designed for different cargo types and logistics needs. This guide classifies the main container families and explains when each type is typically used.

Standard containersVolume-optimizedSpecialized equipment

Container Classification

Three Container Families

All ISO shipping containers fall into three broad families based on their design purpose. Understanding this classification helps operators navigate equipment selection more efficiently.

Family 1

Standard Containers

Fully enclosed, weatherproof steel boxes for general dry cargo. The backbone of global container logistics. Available as 20ft (20DC) and 40ft (40DC) the two most universally available formats.

20ft Dry (20DC)40ft Dry (40DC)

Family 2

Volume-Optimized

One foot taller than standard containers (9'6" vs 8'6"), providing ~13% more internal volume. The 40ft High Cube (40HC) is increasingly replacing the standard 40DC on major trade lanes.

40ft High Cube (40HC)20ft High Cube (rare)

Family 3

Specialized Equipment

Containers engineered for cargo that standard boxes cannot handle, temperature-sensitive goods, oversized equipment, bulk liquids, or top-loaded items. Each type solves a specific logistics constraint.

ReeferFlat RackOpen TopTank Container

Family 1 · Standard Containers

Standard Dry Containers

Dry containers are the backbone of global container logistics. They are fully enclosed, weatherproof steel boxes designed for general-purpose cargo that does not require temperature control or special loading arrangements.

20ft Dry Container (20DC)

Most traded format globally

The most widely traded container format globally. Compact, versatile, and available at virtually every port and depot worldwide. Best suited for heavy or dense cargo where weight limits are reached before volume.

Typical cargo: machinery parts, raw materials, building supplies, packaged goods
Road-weight friendly, stays within truck limits even fully loaded
Universal availability across all major trade lanes

40ft Dry Container (40DC)

Standard FCL format

The standard large-format container for FCL shipments. Offers approximately double the volume of a 20DC, making it cost-effective for lighter, mixed cargo.

Electronics, consumer goods, textiles, palletized freight
Standard for most FCL ocean freight bookings
Balance of volume and cost per unit

Family 2 · Volume-Optimized

High Cube Containers

High Cube containers are one foot taller than standard containers (9'6" vs 8'6" external height), providing approximately 13% more internal volume. The 40ft High Cube (40HC) has become one of the most traded container formats worldwide.

Extra foot of height maximizes volume for lightweight cargo
Preferred for garments, furniture, automotive parts, and retail goods
Widely available on major trade lanes, increasingly replacing standard 40DC
Same external length and width as a standard 40ft container

40HC vs 40DC, Quick Comparison

External height9'6" (2.896 m)8'6" (2.591 m)

Internal volume≈ 76.3 m³≈ 67.7 m³

Volume gain+13%Baseline

Best forLight, bulky cargoStandard mixed cargo

Read full comparison guide

Family 3 · Specialized Equipment

Specialized Container Types

When standard dry containers cannot accommodate the cargo, due to size, shape, weight, or temperature needs, specialized container types provide the solution.

Reefer Containers

20RF / 40RF

Equipped with an integrated refrigeration unit, Reefer containers maintain a constant temperature from -30°C to +30°C. Essential for perishable food, pharmaceuticals, flowers, and chemicals that require cold chain integrity.

Typical cargo: Fresh produce, frozen seafood, dairy, medicines, wine

Flat Rack Containers

20FR / 40FR

Flat Racks have a solid floor with collapsible or fixed end walls but no side walls or roof. They accommodate oversized, heavy, or irregularly shaped cargo that won't fit in enclosed containers.

Typical cargo: Heavy machinery, vehicles, boats, steel structures, turbine blades

Open Top Containers

20OT / 40OT

Open Top containers have a removable roof (tarpaulin or hard top), allowing cargo to be loaded from above using cranes. Ideal for tall items that exceed standard container height.

Typical cargo: Marble slabs, tall equipment, large timber, industrial components

Tank Containers

ISO Tank

ISO tank containers consist of a cylindrical stainless steel tank mounted within a standard container frame. They transport bulk liquids, chemicals, food-grade liquids, and gases safely across all transport modes.

Typical cargo: Chemicals, food-grade oils, wine in bulk, hazardous liquids, gases

Decision Framework

How to Choose the Right Container Type

Container selection is driven by cargo characteristics. Walk through these five factors to match the right equipment to each shipment.

Cargo Weight

Heavy, dense cargo often fits best in 20ft containers due to road weight limits. Lighter cargo can use 40ft or 40HC for volume efficiency.

20DC for heavy · 40HC for light/bulky

Cargo Volume

When volume exceeds weight limits, High Cube containers maximize space. Standard 40ft containers offer a balance between volume and availability.

40HC maximizes cubic capacity

Oversized Cargo

Cargo exceeding container dimensions requires Flat Rack or Open Top containers. Height-restricted cargo may use Open Top; width/length issues need Flat Racks.

Flat Rack or Open Top

Temperature Requirements

Perishable goods, chemicals, or pharmaceuticals require Reefer containers with active temperature control throughout the journey.

Reefer containers required

Loading Constraints

Top-loading for tall items (Open Top), side-loading for wide equipment (Flat Rack), or standard door-end loading (Dry/HC) loading method shapes container choice.

Match loading method to format

Consolidated Reference

Container Types at a Glance

Type	Typical Cargo	Key Advantage	Special Features
20ft Dry (20DC)	Heavy/dense general cargo	Universal availability, road-weight friendly	Most traded unit globally
40ft Dry (40DC)	Mixed general cargo	Balance of volume and cost	Standard for FCL shipments
40ft High Cube (40HC)	Light, voluminous goods	+13% volume vs 40DC	Extra foot of internal height
Reefer (20RF / 40RF)	Temperature-sensitive goods	Active climate control	Integrated cooling/heating unit
Open Top (20OT / 40OT)	Tall or top-loaded cargo	Top-loading capability	Removable roof / tarpaulin cover
Flat Rack (20FR / 40FR)	Oversized / heavy project cargo	No height or width limits	Collapsible or fixed end walls
Tank Container	Bulk liquids, chemicals, gases	Safe liquid transport	ISO-standardized cylindrical tank

20ft Dry (20DC)

Typical Cargo: Heavy/dense general cargo

Key Advantage: Universal availability, road-weight friendly

Special Features: Most traded unit globally

40ft Dry (40DC)

Typical Cargo: Mixed general cargo

Key Advantage: Balance of volume and cost

Special Features: Standard for FCL shipments

40ft High Cube (40HC)

Typical Cargo: Light, voluminous goods

Key Advantage: +13% volume vs 40DC

Special Features: Extra foot of internal height

Reefer (20RF / 40RF)

Typical Cargo: Temperature-sensitive goods

Key Advantage: Active climate control

Special Features: Integrated cooling/heating unit

Open Top (20OT / 40OT)

Typical Cargo: Tall or top-loaded cargo

Key Advantage: Top-loading capability

Special Features: Removable roof / tarpaulin cover

Flat Rack (20FR / 40FR)

Typical Cargo: Oversized / heavy project cargo

Key Advantage: No height or width limits

Special Features: Collapsible or fixed end walls

Tank Container

Typical Cargo: Bulk liquids, chemicals, gases

Key Advantage: Safe liquid transport

Special Features: ISO-standardized cylindrical tank

Frequently Asked Questions

Common Questions About Container Types

The most commonly used shipping containers are 20ft Dry Containers (20DC) and 40ft High Cube Containers (40HC). Together, these two formats account for the vast majority of global container movements. 40ft Dry Containers (40DC) are also widely used. Specialized types like Reefers, Flat Racks, and Open Tops serve specific cargo needs.

The main difference is height. A standard dry container (8'6" external height) provides roughly 33 cubic meters of internal space in 20ft format and 67 m³ in 40ft. A 40ft High Cube container (9'6" external height) provides approximately 76 m³, about 13% more volume. High Cubes are preferred for lightweight, voluminous cargo.

Flat Rack containers are used when cargo is too wide, too tall, or too heavy for standard enclosed containers. Typical uses include heavy machinery, vehicles, boats, construction equipment, and oversized industrial components. Flat Racks allow side and top loading and can handle out-of-gauge dimensions.

Refrigerated containers (Reefers) are required for any temperature-sensitive cargo: fresh and frozen food, dairy, seafood, pharmaceuticals, flowers, and certain chemicals. Reefers maintain a controlled temperature range throughout the voyage, typically from -30°C to +30°C depending on the unit.

Tank containers are ISO-standardized containers with a cylindrical tank mounted inside a standard frame. They are used to transport bulk liquids, chemicals, food-grade liquids, and gases safely by sea, rail, or road. Tank containers are reusable and meet strict international safety standards.

Container selection depends on cargo weight, volume, dimensions, temperature requirements, and loading method. Heavy cargo → 20DC. Light/bulky cargo → 40HC. Oversized → Flat Rack or Open Top. Temperature-sensitive → Reefer. Most standard shipments use dry containers (20DC, 40DC, or 40HC).