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HS codes: how the Harmonized System is built

Read any tariff code at a glance — what the chapter, heading and subheading mean, where the international code ends and national digits begin, and the six rules that decide a product's classification.

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What the HS is

The Harmonized System (HS) is the global product-classification standard maintained by the World Customs Organization (WCO). It is used by more than 200 countries to assess tariffs and compile trade statistics, and it covers the large majority of world merchandise trade. The current edition is HS 2022; the WCO revises it roughly every five years.

How a code is structured

The first six digits are international — identical in every country. They break down in pairs:

DigitsLevelMeaning
09 · digits 1–2ChapterBroad category — e.g. Ch 09 = "Coffee, tea, maté and spices"
0901 · digits 1–4HeadingA product group within the chapter — 0901 = "Coffee"
0901.21 · digits 5–6SubheadingThe specific product — 0901.21 = "Roasted, not decaffeinated"

Beyond the sixth digit, each country adds its own digits for tariff and statistical detail:

  • United States (HTS): 10 digits.
  • European Union (Combined Nomenclature): 8 digits, extended to 10 for TARIC.
  • Most other customs territories: 8–10 digits.

So the first six digits of a code mean the same thing worldwide; only the trailing digits differ by country.

Why classification matters

The HS code determines the duty rate, eligibility for trade-agreement preferences, and any import controls. A wrong code can mean overpaid duty, penalties, or seized goods — which is why importers pay for classification databases the free tools here replace.

Sections & chapters

The HS groups its chapters into 21 Sections, running broadly from raw and natural goods to highly manufactured ones — Section I is live animals and animal products; Section XVII is vehicles and transport equipment. There are 99 chapter numbers: Chapter 77 is reserved for future use, and Chapters 98–99 are left for national use. Section and Chapter Notes are legally binding and often decide a classification on their own.

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The 6 General Rules of Interpretation (GRI)

When a product could fit more than one code, the GRI are applied in order — you only move to the next rule if the current one doesn't settle it.

RuleWhat it says
GRI 1Classify by the terms of the headings and the Section/Chapter Notes. This resolves most cases.
GRI 2(a) Incomplete or unassembled goods are classed as the finished article if they have its essential character. (b) Extends a heading to mixtures and combinations of a material.
GRI 3If two+ headings apply: (a) the most specific wins; (b) else classify by essential character; (c) else take the heading last in numerical order.
GRI 4If still unclassified, use the heading for the goods most akin (rarely needed).
GRI 5Cases, packaging and containers are usually classed with the goods they hold.
GRI 6Compare subheadings only with subheadings of the same level — the GRI repeat at the 6-digit level.

Common mistakes

  • Ignoring the Section/Chapter Notes. They are legally binding and frequently exclude a product from the "obvious" heading.
  • Skipping the GRI order. You must exhaust GRI 1 before reaching for essential character under GRI 3(b).
  • Assuming codes match across countries beyond 6 digits. A US 10-digit HTS code is not an EU 8-digit CN code.
  • Classifying on marketing name, not function/material. The HS cares what a thing is, not what it's called.

Sources

  1. World Customs Organization — HS Nomenclature 2022 Edition.
  2. WCO, General Rules for the Interpretation of the Harmonized System.
  3. U.S. International Trade Commission — Harmonized Tariff Schedule (HTS); EU TARIC for the Combined Nomenclature.

Reference summary only. Classification decisions for live shipments should be confirmed with the relevant customs authority or a licensed broker.