Containers intended for intercontinental use have external nominal dimensions of:

All above dimensions have permissible tolerances.

The 20 feet (20') and 40 feet (40') containers are very popular in ocean freight. The 8.5 feet (8.5') high container---8 feet 6 inches (8' 6") high container---is often referred to as standard container.

The demand for the high cube container---hicube---is increasing. The popular high cube container has a normal height of 9.5 feet (9.5' or 9' 6").

There are half height containers (4.25' or 4' 3" high) designed for heavy loads such as steel rods and ingots, which absorb the weight limit in half the normal space.

The most widely used type of container is the general purpose (dry cargo) container (please see Container Classifications) having a nominal length and height of 20' x 8.5', 40' x 8.5', and 40' x 9.5'. Referring to the Dimension of General Purpose Containers below, the dimensions shown in the table are not fixed, that is, the external and internal dimensions may vary among containers of the same length and height.

The container capacity is the total cube a container can accommodate. The term cube often refers to the cubic measurement of cargo. The capacity (i.e., the internal volume) is determined by multiplying the internal dimensions, that is, the product of internal length, width and height. The capacity may vary among containers of the same length and height.

Rating

Rating is the maximum gross mass (or weight), that is, the maximum permissible weight of a container plus its contents. The rating of a 20' dry cargo container is 24,000 kgs. (52,900 lbs.), and a 40', including the high cube container, is 30,480 kgs. (67,200 lbs.).

Tare Mass

Tare Mass---tare weight or tare---is the mass (or weight) of empty container, including all fittings and appliances used in a particular type of container in its normal operating condition.

The tare mass of containers may vary due to the different construction techniques and materials used in the container. A 20' x 8.5' dry cargo container may weigh 1,800 kgs. to 2,400 kgs., a 40' x 8.5' may weigh 2,800 kgs. to 4,000 kgs, and a 40' x 9.5' may weigh 3,900 kgs. to 4,200 kgs. Some dry cargo containers may fall outside the indicated weight range. The reefer weighs more than a dry cargo container of the same size.

Payload

Payload is the maximum permitted mass (or weight) of payload, including the dunnage and cargo securement arrangements that are not associated with the container in its normal operating condition. Therefore, Payload = Rating - Tare Mass.

If the tare mass of a 20' dry cargo container is 2,400 kgs. and a 40' is 3,900 kgs., the payload of 20' is 21,600 kgs. (i.e., 24,000 kgs. minus 2,400 kgs.) and 40' is 26,580 kgs. (i.e., 30,480 kgs. minus 3,900 kgs.). However, the exporter may be prohibited to have that much payload in areas where there are legal limitations to the overall load of a vehicle.

In exporting, it is common to encounter a payload of 17,500 kgs. or less in the 20' container, and 24,000 kgs. or less in the 40' container.

The rating, tare mass and payload of a container is marked on its wall, usually on the end (rear) door in the case of an end-loading dry cargo container.

Each container has an identification code or container number---a combination of the 4-letter characters that identify the owner (the operator of container) and the 7-numeric characters that identify the container. The container number can be found on the outer and inner side walls.

The container number is entered on the bill of lading to facilitate the identification and tracking of the container and the cargo.