TEU (Twenty-foot equivalent unit)

A standard unit based on an ISO container of 20 feet in length (6.10 m), used as a measure for shipping containers of various storage capacities, as well as for the capacity of container vessels and terminals.

One 20-foot ISO container (6.10 m) equals 1 TEU.
One 40-foot ISO container equals 2 TEUs.
One container of more than 20 feet and less than 40 feet equals 1.50 TEU.
One container of more than 40 feet equals 2.25 TEUs.