Tariff Classification: How to Classify US Imports

Tariff classification is the process of assigning each imported product a code in the Harmonized Tariff Schedule of the United States (HTSUS) — the code that decides your duty rate and which trade rules apply. Classification is the importer’s legal responsibility, and it is the single decision that drives almost everything else about your entry: the duty owed, whether antidumping or Section 301 duties attach, and whether another agency (FDA, EPA, CPSC) has to clear the shipment.

This guide explains how HTS codes are built, the legal rules CBP uses to classify, and how to lock in a correct answer with a binding ruling.

What an HTS Code Is

The HTSUS is built on the international Harmonized System (HS), maintained by the World Customs Organization and used by most trading nations. The structure layers from general to specific:

So the first six digits of your code are the same in Germany or Vietnam, but digits 7–10 are uniquely U.S. and determine what you actually pay. The HTSUS is published by the U.S. International Trade Commission; CBP enforces it at the border.

The General Rules of Interpretation

Classification is not a guessing game or a search for the closest-sounding description. It follows six General Rules of Interpretation (GRIs), applied in order, plus the Additional U.S. Rules of Interpretation:

• GRI 1 — Classify according to the terms of the headings and any relevant section or chapter notes. This resolves most products.
• GRI 2 — Covers incomplete or unfinished articles (if they have the essential character of the finished good) and mixtures or combinations.
• GRI 3 — When goods are prima facie classifiable under two or more headings, choose the most specific heading; failing that, the component that gives the goods their essential character; failing that, the heading that occurs last in numerical order.
• GRI 4 — Goods that cannot be classified by the above go to the heading for the most similar goods.
• GRI 5 — Rules for cases, containers, and packing materials.
• GRI 6 — Applies the same logic at the subheading level.

The discipline of working GRI 1 first — reading the headings and the legal notes before reaching for “essential character” — is what separates a defensible classification from a convenient one.

Common Classification Mistakes

• Classifying by marketing description instead of the heading terms and notes.
• Ignoring section and chapter notes, which can expressly include or exclude your product.
• Assuming the supplier’s code is right — a foreign HS code only covers the first six digits and was chosen for that country’s schedule, not yours.
• Reusing a code after the product changes in composition, function, or design.

Each of these can mean overpaying duty for years or, worse, underpaying and facing a penalty.

Lock It In With a Binding Ruling

If a classification is unclear or high-stakes, you do not have to guess. CBP issues binding rulings under 19 CFR Part 177. You submit a request through CBP’s eRulings portal describing the product, and CBP returns a classification that is legally binding on the agency at every port. Past rulings are searchable in CBP’s public CROSS database, which is the best starting point for researching how CBP has treated similar goods.

A binding ruling is the cleanest way to remove classification risk before you import in volume — particularly for novel products, borderline cases, or items where a few duty percentage points matter at scale.

Why Getting It Right Matters

Classification is governed by the importer’s duty of reasonable care under 19 U.S.C. § 1484. A wrong code is not a harmless filing error: it can misstate the duty owed, pull goods into or out of antidumping/countervailing or special-tariff scope, and create exposure under 19 U.S.C. § 1592. If you discover a past error, a prior disclosure to CBP can substantially reduce penalties.

Classification also feeds directly into the rest of the entry: the code sets the rate used in your duty and tax calculation, and it interacts with country-of-origin marking and customs valuation.

Frequently Asked Questions

What is an HTS code?

It is the numeric classification of a product in the Harmonized Tariff Schedule of the United States. The first six digits are an international Harmonized System subheading; the U.S. extends the code to ten digits, with the duty rate set at the eighth digit.

Who is responsible for classifying my imports?

The importer of record, under the reasonable-care standard of 19 U.S.C. § 1484. Even if a customs broker files the entry, the legal responsibility for the classification stays with you.

How do the General Rules of Interpretation work?

The six GRIs are applied in order. GRI 1 — the terms of the headings and the section/chapter notes — resolves most products. The later rules handle unfinished goods, mixtures, “essential character,” and subheading-level decisions.

What is a CBP binding ruling?

A written classification (or valuation/origin) decision CBP issues on request that legally binds the agency. You request one through CBP’s eRulings portal, and prior rulings are searchable in the CROSS database.

The right HTS code protects your duty rate and keeps your entries clean across every port. Reidel Law Firm provides import and export compliance counsel — including classification opinions and binding-ruling requests — for a predictable flat fee: get a flat-fee compliance memo before your next entry.