The Harmonized System (HS) for Export Classification

The Harmonized System (HS) is the six-digit product-coding language used by more than 200 countries to classify traded goods — and it is the foundation of every U.S. export classification, which extends the HS into a 10-digit Schedule B number. If you export from the United States, the HS is where your product’s identity begins, and getting it right is what keeps your shipments reported correctly and your export filings clean.

What the Harmonized System is

The HS is an international nomenclature — a structured list of product categories, each with a numeric code — maintained by the World Customs Organization (WCO). Its purpose is to give every country a common way to describe goods so that the same product carries the same six-digit code in New York, Hamburg, and Shanghai.

That common language does a lot of work. It lets customs authorities apply duties consistently, lets governments compile comparable trade statistics, and gives importers and exporters a shared reference point when they describe goods to each other. Roughly 98% of merchandise in international trade is classified under the HS.

A short history

The WCO began life in 1952 as the Customs Co-operation Council and was renamed the World Customs Organization in 1994. The HS itself came later: the International Convention on the Harmonized Commodity Description and Coding System — the “HS Convention” — entered into force on 1 January 1988, replacing the patchwork of earlier national systems with one shared framework.

The WCO updates the HS on a multi-year cycle so it can keep pace with new products and trade patterns. The current edition is HS 2022. The next revision was originally planned for 2027 but, after a one-year extension, will take effect on 1 January 2028 (the WCO published the HS 2028 changes and correlation tables in 2026). Each revision adds, merges, or re-numbers headings, so exporters should re-check their codes when a new edition lands.

How an HS code is structured

The six digits of an HS code are read in pairs, moving from broad to specific:

Every country that uses the HS shares these six digits for a given product. What changes from country to country is what gets added after the sixth digit.

From HS to U.S. Schedule B

For U.S. exports, the six-digit HS code is extended into a 10-digit Schedule B number, administered by the U.S. Census Bureau’s Foreign Trade Division. The first six digits are the international HS code; the last four are a U.S. statistical extension used to track exports in detail.

Schedule B numbers are reported in the Electronic Export Information (EEI) filed through the Automated Export System (AES) for shipments above the reporting threshold. Because Schedule B exists for statistics rather than duty collection (the U.S. generally does not tax exports), its job is to measure what leaves the country accurately. The authoritative way to find a number is the Census Schedule B Search tool.

It helps to keep three points straight:

• HS (6 digits) is the international core, set by the WCO.
• Schedule B (10 digits) is the U.S. export extension, set by the Census Bureau.
• HTS (10 digits) is the U.S. import extension, set by the International Trade Commission — a different last four digits, for duties. See how the two extensions relate in our guide to import vs. export classification.

Classification is not the same as export controls

A correct Schedule B number tells you how to report an export. It does not tell you whether you are allowed to export the item without a license. That question runs through a separate system — the Export Control Classification Number (ECCN) under the Export Administration Regulations, administered by the Bureau of Industry and Security. For sensitive or dual-use goods, you need both: the Schedule B number for reporting and the ECCN analysis for licensing. Treating them as one thing is a common and costly mistake.

Getting export classification right

The exporter — or its authorized agent — is legally responsible for classifying goods correctly and filing accurate export information under a “reasonable care” standard. Practical habits that prevent problems:

• Start from the product’s actual characteristics — material, function, and use — not a guess based on its name.
• Find the six-digit HS subheading first, then extend to the full Schedule B number using the Census search tool.
• Re-verify codes when the HS is revised (next, for HS 2028) or when your product changes.
• Run a separate export-control check for any item that could be controlled or dual-use.
• Document the reasoning so your filings are defensible if questioned.

For the broader legal picture around exporting, see our overview of international trade law.

Frequently asked questions

What is the difference between an HS code and a Schedule B number? An HS code is the international six-digit code set by the World Customs Organization. A Schedule B number is the 10-digit U.S. export code that begins with those six HS digits and adds four U.S. statistical digits. You report exports using Schedule B.

Who maintains the Harmonized System? The World Customs Organization maintains the HS and revises it on a multi-year cycle. The current edition is HS 2022; the next edition takes effect 1 January 2028.

Where do I find my product’s Schedule B number? Use the U.S. Census Bureau’s Schedule B Search tool. Identify the correct six-digit HS subheading first, then select the full 10-digit Schedule B number.

Does a Schedule B number tell me if I need an export license? No. Licensing turns on the Export Control Classification Number under the Export Administration Regulations, a separate system administered by the Bureau of Industry and Security. Classification and export controls are two different analyses.

Exporting and want your classifications and license posture confirmed? Reidel Law Firm delivers a flat-fee import/export compliance memo that pins down your Schedule B classification, export-control exposure, and filing obligations in plain English, with direct attorney access. Get a flat-fee compliance memo →