The Harmonized Commodity Description and Coding System

The Harmonized Commodity Description and Coding System (HS) of tariff nomenclature is an internationally standardized system of names and numbers for classifying traded products developed and maintained by the World Customs Organization (WCO) (formerly the Customs Co-operation Council), an independent intergovernmental organization with over 170 member countries based in Brussels, Belgium.

Under the HS Convention, the contracting parties are obliged to base their tariff schedules on the HS nomenclature, although parties set their own rates of duty. The system begins by assigning goods to categories of crude and natural products, and from there proceeds to categories with increasing complexity. The codes with the broadest coverage are the first four digits, and are referred to as the heading. The HTS therefore sets forth all the international nomenclature through the 6-digit level and, where needed, contains added subdivisions assigned 2 more digits, for a total of 8 at the tariff-rate line (legal) level. Two final (non-legal) digits are assigned as statistical reporting numbers if warranted, for a total of 10 digits to be listed on entries.

To ensure harmonization, the contracting parties must employ all 4- and 6-digit provisions and the international rules and notes without deviation, but are free to adopt additional subcategories and notes.