{"id":2912,"date":"2025-10-21T21:49:03","date_gmt":"2025-10-21T19:49:03","guid":{"rendered":"https:\/\/chswmco.wpenginepowered.com\/us\/?p=2912"},"modified":"2025-11-19T18:48:33","modified_gmt":"2025-11-19T17:48:33","slug":"iso-668","status":"publish","type":"post","link":"https:\/\/chs-containergroup.com\/us\/iso-668\/","title":{"rendered":"Quick Guide: What is ISO 668?"},"content":{"rendered":"\n

Ever wondered why a 20ft shipping container isn\u2019t actually<\/em> 20 feet long? The answer lies in ISO 668<\/strong>: a global standard for how containers are built and measured. In this article, we\u2019ll look at what ISO 668 is and how it helped shape intermodal transport as we know it.<\/p>\n\n\n\n

What is ISO 668?<\/h2>\n\n\n\n

ISO 668 is an international standard that defines the external dimensions, weight limits, and structural requirements for freight containers used in intermodal transport. First published in 1968 by the International Organization for Standardization (ISO), the regulation established standardized container sizes that made intermodal trade possible and today allows the liner shipping industry to move an estimated $4 trillion in goods each year<\/a>.<\/p>\n\n\n\n

Freight Transport Prior to ISO 668<\/h2>\n\n\n\n

The story of container transport begins in the 18th century, when standardized wooden boxes were used to move coal within the mining regions of England and Wales. By the early 1900s, this idea had evolved into closed containers\u2014made with wood or iron\u2014that could be transported by rail or road, laying the groundwork for modern intermodal shipping.<\/p>\n\n\n\n

The first international container standard appeared in 1933, created by the Bureau International des Containers et du Transport Intermodal (BIC)<\/a> in a bid to standardize containers used for trade between European countries. This early framework had major limitations by modern standards: containers were not stackable, nor were they designed for intercontinental or intermodal use.<\/p>\n\n\n\n

In the 1950s, Malcolm McLean\u2019s Sea-Land containers and advances in telecommunications fueled interest in creating a \u201cshared language\u201d for containerized transport. Container sizes, corner fittings, and designs still varied widely by region, and cargo often had to be unloaded from one container and reloaded into another, adding time, cost, and safety risks to the transport process.<\/p>\n\n\n\n

In 1968, ISO Technical Committee 104 (ISO\/TC 104) established ISO 668, introducing the uniform container dimensions, fittings, and tolerances that make intermodal transport possible today.<\/p>\n\n\n\n

ISO 668 Specifications<\/h2>\n\n\n\n

ISO 668 sets size and weight requirements for Series 1 containers used in intercontinental traffic, including:<\/p>\n\n\n\n