HS code classification is the fundamental building block of customs declarations worldwide. An incorrect HS code can result in wrong duty rates, compliance violations, and potential penalties. Mastering the classification methodology is essential for trade professionals.

HS codes follow six General Rules of Interpretation. The core principle is that goods should be classified according to their essential character rather than their trade name. Classification proceeds hierarchically through sections, chapters, headings, and subheadings.
Frequent errors include classifying by product name alone without considering function, ignoring material composition, and confusing parts with complete machines. A single digit error in HS code can lead to duty rate differences exceeding 10%.