ISO 668: container classification and ratings

ISO 668 classifies series 1 freight containers by external dimensions and states their ratings. The current edition is ISO 668:2020, the seventh, amended by ISO 668:2020/Amd 1:2022, which replaced Table 2 and set the rating at 36,000 kg for every designation except the 10 ft 1D and 1DX at 10,160 kg.

What the standard does not carry is internal cubic capacity. Its clause 1 states that ISO 1496 is the authoritative document for internal container dimensions, and its Table 3 gives only minima: 2,330 mm minimum internal width for every series 1 container, and a minimum door width of 2,286 mm. The capacities quoted in the trade are carrier and manufacturer figures derived from as-built dimensions.

The full article will cover the designation system and the height and length families, the external dimensions and their tolerances, the minimum internal and door-opening dimensions, and the rating history from the 2005 amendment that raised the 20 ft and 30 ft classes to 30,480 kg through the 2016 permission and the 2022 amendment. The practical consequences for cargo planning are in CBM and chargeable weight .