HTSUS Structure

Additional U.S. Notes are provisions unique to the HTSUS with no international HS equivalent. They define terms, set tariff-rate quota conditions, and modify duty rates for specific products.

A chapter is a 2-digit grouping of related headings in the HTSUS. The HTSUS contains 97 active chapters, each with legally binding chapter notes that must be evaluated before any heading analysis under GRI 1.

Chapter notes are legally binding notes specific to a single HTSUS chapter. They take precedence over heading text and must be applied under GRI 1 before any heading comparison is made.

An HTS code is the 8–10 digit number derived from the HTSUS that determines the duty rate, trade remedy exposure, and regulatory requirements for an imported product.

The HTSUS classifies imports (administered by CBP); Schedule B classifies exports (administered by Census). They share the same 6-digit HS foundation but diverge at digits 7–10.

The Harmonized System is the international 6-digit product nomenclature developed by the World Customs Organization and used by 200+ countries as the foundation for national tariff schedules.

The HTSUS is the legal tariff schedule published by the USITC that governs the classification and duty rates for all goods imported into the United States.

A heading is a 4-digit provision in the HTSUS that defines the scope of a primary product category. All HTSUS classification begins at the heading level under GRI 1, read together with applicable section and chapter notes.

Looking up a Schedule B number? Here's what it is, how it relates to your HTS import code, and where to find the Census Bureau's official search tool.

The HTSUS is organized into 22 sections, each grouping related chapters under a broad product category. Section notes are legally binding, apply to all headings within the section, and must be evaluated before any heading analysis under GRI 1.

Section notes are legally binding notes that apply to an entire HTSUS section. Under GRI 1, they are the first text consulted — a section note can exclude, define, or redirect classification before any heading is considered.

The statistical suffix is digits 9–10 of a 10-digit HTS code. It is required on formal entry documents and, in some trade remedy contexts, determines whether an overlay duty applies.

A subheading is a 6- or 8-digit provision in the HTSUS that further subdivides a heading. Subheading classification is governed by GRI 6 and can only proceed after heading-level classification is resolved.

Subheading notes apply only at the 6-digit subheading level under GRI 6. They cannot be used to resolve heading-level classification — applying them at the wrong level is a legal error.

A tariff provision is any enumerated entry in the HTSUS — a heading, subheading, or Chapter 99 overlay — that carries legal significance for classification, duty rates, or trade remedy applicability.

The ten-digit HTS code is the complete, fully-resolved classification number for an imported good. Digits 1–4 are the heading, 5–6 the first-level subheading, 7–8 the second-level subheading, and 9–10 the statistical suffix.

The USITC is the independent federal agency that publishes and maintains the HTSUS, issues annual tariff schedule updates, and conducts injury investigations in trade remedy proceedings.