Not all containers are the same box in two lengths. Choosing the right type and size affects how much you can load, what you can ship, and what you pay. Here is a practical reference to the equipment you will actually encounter.

The standard dry containers

The workhorses of ocean freight are general-purpose steel boxes:

20ft standard — roughly 33 cbm of internal volume, with a payload commonly around 28 tonnes depending on the line. Good for dense, heavy cargo that “weighs out” before it “cubes out.”
40ft standard — roughly 67 cbm. The default for most full-container shipments; double the space of a 20ft for less than double the cost.

A useful rule: heavy cargo often fills a 20ft on weight; light, bulky cargo benefits from the extra volume of a 40ft.

High-cube containers

40ft high-cube (40HC) — the same footprint as a 40ft standard but about a foot taller, giving roughly 76 cbm. It has become the most common box on many lanes because the extra height is “free” volume for lightweight cargo. 45ft high-cube options exist on some routes for even more space.

Temperature-controlled (reefer)

Reefer containers — refrigerated boxes for perishables, pharmaceuticals and other temperature-sensitive cargo. Available in 20ft and 40ft high-cube. They cost more and need a power supply, but they hold a set temperature throughout the journey.

Specialised containers

For cargo that will not fit a standard box:

Open-top — an open roof covered by a tarpaulin, for tall cargo loaded by crane.
Flat-rack — collapsible or fixed sides, for oversized, heavy or awkwardly shaped items like machinery and vehicles.
Open-side — doors along the full length, for cargo that must be loaded from the side.
Tank containers — for liquids and gases in bulk.

Choosing the right box

Three questions usually settle it:

How much volume and weight? This decides 20ft vs 40ft, standard vs high-cube.
Does it fit through standard doors? If not, you are looking at open-top, flat-rack or open-side.
Does it need temperature control or special handling? That points to a reefer or specialised equipment.

The bottom line

For most goods, the choice is simply 20ft, 40ft or 40HC, driven by your weight and volume. Match the box to your cargo’s density first — heavy goods to a 20ft, bulky goods to a high-cube — and reach for specialised equipment only when size, shape or temperature demands it. A forwarder can confirm the most cost-effective option once they know your dimensions and weight.

Shipping Container Types and Sizes: A Practical Reference