The Combined Nomenclature (CN) of the European Union was introduced as an 8-digit nomenclature at the same time as the Harmonized System (HS). The HS is the basis of the CN, whereby the 6-digit subheadings of the HS have been extended to 8-digit subheadings.

As with the HS, the CN is divided into 21 sections and 97 chapters, whereby chapter 77 contains no commodities. The CN is updated annually and each amended version is valid as of 1 January of the following year.

Commodities which are declared to the customs authorities of the European Community must be classified according to the CN. The relevant subheading of the product must be stated in the import and export declarations.

Certain partner states of the European Union have made the CN the basis of their customs tariffs and thus this nomenclature may be referred to as a regional customs tariff nomenclature.

Overview of the make-up of a 4-digit to 8-digit product code: