Twenty-foot equivalent unit

The twenty-foot equivalent unit (abbreviated TEU or teu) is an inexact unit of cargo capacity, often used for container ships and container ports.[1] It is based on the volume of a 20-foot-long (6.1 m) intermodal container, a standard-sized metal box which can be easily transferred between different modes of transportation, such as ships, trains, and trucks.[1]

A 20-foot-long (6.1 m) ISO container equals 1 TEU.
Two forty-foot containers stacked on top of two twenty-foot containers. These four containers represent 6 TEU.

The container is defined by its length, although the height is not standardized and ranges between 4 feet 3 inches (1.30 m) and 9 feet 6 inches (2.90 m), with the most common height being 8 feet 6 inches (2.59 m).[2] It is common to designate a 45-foot (13.7 m) container as 2 TEU, rather than 2.25 TEU.