Guide

HS structure

Understand how HS codes are structured (chapters, headings, subheadings) and where ambiguity commonly occurs.

How HS codes are organized

The Harmonized System (HS) is a shared international structure for describing goods. The first 6 digits are harmonized. Many countries add national extensions (often 8–12+ digits) to apply local duty rates, measures, and statistical reporting.

LevelDigitsWhat it represents
Chapter2Broad family of goods
Heading4Narrower family inside a chapter
Subheading6Internationally harmonized detail level
National extension8–12+Local measures, duty rates, reporting detail

Where ambiguity happens

  • Multi-material goods: dominant material is not always obvious, especially with coatings or composites.
  • Sets and kits: classification can depend on how items are packaged and whether they form a set.
  • Parts vs complete articles: a “part” is not simply anything sold separately.
  • Function vs description: two products can look similar but operate differently, leading to different headings.

How to use this site with HS structure

  1. Write a neutral product description (material + function + key technical characteristics).
  2. Capture deciding facts (composition, completeness, operating principle, specs).
  3. Compare plausible headings at a high level (chapter/heading), then route to an official database for rates.

This site does not provide official classifications. It is designed to help you prepare a fact set that makes official lookup faster and less error-prone.

Next step
Use Lookup to capture deciding facts, then open Official tools for the jurisdiction-specific tariff database.