The Harmonized Tariff Schedule (HTS): How to Read and Use It

What Is the Harmonized Tariff Schedule?

The Harmonized Tariff Schedule of the United States (HTSUS) is the official schedule of import duties for goods entering the United States. It's maintained by the US International Trade Commission (USITC) and is the legal authority for every customs duty calculation. Your customs broker files your entry against codes from this schedule; CBP audits those entries against this schedule.

The schedule is available free at hts.usitc.gov and is updated annually (with interim updates for urgent tariff changes). It contains approximately 10,000 statistical subheadings, organized into 21 Sections, 99 Chapters, and thousands of headings and subheadings.

The Structure of the HTS

Sections and Chapters

The HTS is divided into 21 Sections. Each Section is divided into Chapters — 97 active Chapters (Chapter 77 is reserved; Chapter 98 covers goods returning to the US; Chapter 99 covers special tariff provisions). Chapters are identified by a two-digit number (01 through 99).

Section and Chapter Notes

Each Section and each Chapter begins with legal notes. These notes define terms, exclude products from the chapter, and specify how certain goods must be classified. They have the force of law and take precedence over heading text. This is where most classification disputes originate — a product that seems to fit a heading based on its description is excluded by a note, or vice versa.

Always read the relevant Section and Chapter notes before finalizing a classification. The heading text alone is not sufficient.

How to Navigate hts.usitc.gov

The USITC website provides several ways to find the right code:

• Browse by chapter: Click into the chapter for your product category and drill down through headings and subheadings
• Search by keyword: The built-in search returns headings that contain your search term in their description. Use product-specific terms, not generic ones.
• Search by HTS number: Enter a known code (4, 6, 8, or 10 digits) to jump directly to that level of the schedule

The interface can be dense. Alternatively, use our free HTS lookup tool, which lets you describe your product in plain English and returns the matching 10-digit code, duty rate, and Section 301 status.

Reading the Duty Rate Columns

Each HTS subheading has multiple rate columns. Here's what they mean:

For most importers, Column 1 General is what you pay. The special column rates apply only if your goods qualify under a specific trade program — indicated by a letter code in parentheses next to the rate.

Special Program Indicators (SPIs)

The Column 1 Special rates show a letter code for each applicable trade program:

To claim a preferential rate, you must have documentation proving origin in the qualifying country (usually a certificate of origin or producer declaration). Simply shipping from the country isn't enough.

Chapter 99: The Special Tariff Chapter

Chapter 99 is where special tariff provisions live — the ones that don't fit neatly into the product-based chapters 01–97. For ecommerce importers, Chapter 99 is important for two reasons:

Section 301 tariffs

The Section 301 tariffs on Chinese-origin goods are collected through Chapter 99 subheadings. When you look up a code and see a footnote in the rate column referencing Chapter 99 (e.g., “See subheadings 9903.88.01–9903.88.55”), that's the signal that your product may be subject to an additional 7.5%, 25%, or higher Section 301 rate if it's Chinese origin.

These Chapter 99 overlays are in addition to the Column 1 General rate — they stack on top. Your customs broker should be applying both rates when calculating your total duty owed.

IEEPA tariffs

The IEEPA emergency tariffs imposed in 2025 are also collected through Chapter 99 references. Check the most current schedule for applicable subheadings, as these have been subject to rapid changes.

Exclusions

Chapter 99 also contains product exclusions — specific codes where the Section 301 tariff is waived. These exclusions are narrow (specific 10-digit codes or product descriptions), time-limited, and must be claimed on the entry by citing the exclusion subheading.

How the HTS Is Updated

The base HS system is revised every five years by the WCO (most recently in 2022). When the HS is revised, the USITC updates the HTS to incorporate the new international classification structure. Products may move to new codes, codes may be split or merged, and importers must reclassify products accordingly.

Between HS revision cycles, the USITC can and does update the HTS for domestic policy reasons — adding statistical suffixes, adjusting duty rates, implementing tariff actions. Check the USITC website at the start of each year for the current schedule.

Using the HTS Alongside This Guide

The HTS is a primary source. Use it to verify codes, check current rates, and read the legal notes that govern your classification. But the HTS alone doesn't tell you which code is correct for your specific product — that requires applying the General Rules of Interpretation.

Read our HTS classification guide for a complete walkthrough of the GRIs and how to apply them. And read our HS vs HTS explainer to understand why the last four digits of your code matter as much as the first six.

To look up any 4-digit HTS heading and run a full classification on your product, use our free HTS lookup tool — or sign up for a full audit to check your entire product catalog against the current schedule.