HS uses number code in classifying goods. The number code represents the goods description which is composed systematically. The numbering system in HS is divided into Chapter (2-digits), heading (4-digits), and sub-heading (6-digits) with the following explanations:
For example, code HS 0101.11.xx.xx taken from BTBMI (10 digits)
01 01 11 xx xx
__ Chapter 1
_____ Heading 01. 01
________ Sub-heading 0101. 11
___________ Sub-heading ASEAN, ASEAN Harmonized Tariff Nomenclature (AHTN)
______________ Heading Indonesia Customs Tariff Book (BTKI)
HS has a six-digits number for the classification, each country that signed the HS convention or contracting Party can develop a classification of six-digit number to be more specific in accordance with respective Government policy while remains under the provisions of the HS six-digits. In Indonesia alone, the classification system uses 10-digits numbering system in Indonesia Customs Tariff Book (BTKI) which is a further elaboration of the sub-headings in the HS six-digit.