An HTS code is a 10-digit number that identifies a specific product for U.S. customs purposes. Every commercial shipment entering the United States must be classified with an HTS code, which determines the duty rate, any applicable trade program eligibility, and statistical reporting requirements. The code is drawn from the Harmonized Tariff Schedule, published by the U.S. International Trade Commission.
Why It Matters for Importers
Your HTS code is the single most important number on a customs entry. It determines how much you pay in duties, whether your product qualifies for preferential treatment under a free trade agreement, and whether additional tariffs — such as Section 301 or antidumping duties — apply. An incorrect HTS code can result in overpaid duties, underpaid duties (which triggers penalties), or shipment delays at the port.
CBP holds the importer of record legally responsible for correct classification. This obligation exists regardless of whether you use a customs broker to file your entries. If your broker classifies a product incorrectly, CBP can assess penalties against you, not the broker.
How HTS Codes Are Structured
- Digits 1-2 (Chapter): Broad product category. For example, Chapter 61 covers knitted apparel; Chapter 84 covers machinery.
- Digits 1-4 (Heading): Narrows the product type within the chapter.
- Digits 1-6 (Subheading): Internationally standardized under the Harmonized System (HS). The same six digits apply in nearly every country worldwide.
- Digits 7-8: U.S.-specific rate line that determines the applicable duty rate.
- Digits 9-10: Statistical suffix used for trade data reporting. Does not affect duty rates.
Common Mistakes
Many importers search for HTS codes using product descriptions or keyword tools. This approach frequently produces incorrect results because the HTS is a legal document governed by the General Rules of Interpretation — not a product catalog. The correct classification depends on the product's material composition, function, and intended use, not its marketing name.
Classification errors account for 42% of all CBP penalty cases. An experienced customs broker classifies products based on the legal text of the tariff schedule and binding rulings from CBP. Learn more about the risks and costs of getting this wrong in our guide on HTS classification errors.