First, the short version of how the number works
The Harmonized System is a global numbering scheme maintained by the World Customs Organization. Every country that uses it — and virtually all do — shares the first six digits. Beyond that, countries add their own digits to split the world's goods into the specific lines they actually tax. The US uses 8 and 10 digits (the HTSUS), the EU uses 8 in TARIC, the UK uses 8 in its UK Global Tariff, and the extra digits are where the real rates live.
Concretely: 6110.20 is a men's knitted cotton sweater in every country that uses the system — chapter 61 (knitted garments), heading 10 (sweaters, pullovers), subheading 20 (cotton). When the US adds two more digits to get 6110.20.30, that's where the exact duty rate and any trade-remedy exposure actually sits. So the question "what's my HS code" usually means one of two things: the 6-digit global code, or the 10-digit US code that decides your bill. This guide handles both.
Path one: describe the goods, then search
This is the method that works, and it starts with words, not numbers. Before you touch a tariff schedule, write down three things about your product: what it is made of, what it does, and how it's sold. A plastic storage box for a workshop is classified as a plastic article (Chapter 39), not as furniture (Chapter 94), not as a container for transport (Chapter 42) — and a hobbyist who calls it "furniture" will pay 8% instead of 3.5%. The material and the function are the two levers customs uses to sort everything.
Once you have that description, you have two free places to search. Our HS code estimator gives a quick global baseline by keyword, and the tariff rate lookup lets you check the resulting rate across markets. For the official version, the USITC maintains the full searchable HTSUS online at hts.usitc.gov — type "cotton sweater" and it walks you to Chapter 61. The EU's TARIC and the UK's Trade Tariff tool work the same way for those markets.
Start wide and narrow down. If you sell an electric food mixer, do not search "mixer." Search "kitchen appliances" or go straight to Chapter 85 and read the heading descriptions until one matches your machine's function. The headings are written in deliberately careful language, and the words matter: heading 8509 covers electromechanical domestic appliances, but only "with self-contained electric motor" — a stand mixer qualifies, a hand whisk that plugs into a wall socket may not. Reading the heading text is not optional homework; it is the actual mechanism of classification.
Path two: the supplier's code — use it, don't trust it
Nine out of ten Chinese suppliers will happily put an HS code on the invoice. Treat it as a hint, not an answer. The supplier is usually quoting the 6-digit code for their own export declaration, and it is often wrong for the US side in one of two ways: it may be a simplified "general" code that lumps your product into a higher-rate line, or it may be an export-oriented classification that doesn't match how US customs treats the goods. We have seen a shipment of silicone phone cases invoiced under a rubber code that carried an AD/CVD case, and a toy code that turned a decorative item into a mandatory-licensing product.
The reliable way to use a supplier's code: take it as a starting point, look up the same product description in the US schedule, and compare. If your supplier's 6-digit code lands you in a completely different chapter than the US description suggests, trust the schedule. The commodity codes page shows how much the same goods can differ between jurisdictions — the supplier's country classifies for its own export rules, which are not your import rules.
The classification traps that actually cost money
After years of watching importers' entries, these are the mistakes that recur. None of them are exotic legal theories — they are everyday goods filed under the wrong heading.
- Material vs. function. A plastic part of a machine is not automatically a plastic article. If the part is identifiable as a machine component, it is usually classified as a part of that machine (Chapter 84/85), often at a lower rate than the plastic-article heading. But a generic plastic box or bottle is a plastic article. The test is whether the item is shaped specifically for the machine or generic.
- Sets and combinations. A gift set of a mug plus a spoon plus a candle is not three separate classifications — under the General Rules of Interpretation, a set is classified by the component that gives it its essential character. That rule (GRI 3) decides the duty for countless e-commerce bundles, and it favors the component that makes the set what it is, not the most expensive one.
- Multi-function devices. A device that prints, scans, and copies is classified by its principal function. A printer that happens to scan is a printer (8443), not a multi-function office machine (9009) and not a scanner (8471). The principal-function test produces frequent disputes, and it is worth checking a ruling on your exact device before you file.
- Parts vs. finished goods. "Parts" are classified by the machine they belong to, and parts headings are usually cheaper than the finished machine. But a part that is separately identifiable as a finished article of commerce in its own right — a screw, a battery, a cable — gets its own heading, sometimes at a higher rate.
- Copying a code from a similar product. Two items that look alike in a photo can be very different in the schedule. A "leather-look" wallet in PVC is a plastic article (3926 or 4202 depending on construction), while a genuine leather wallet is Chapter 42 — the difference can be several percentage points, and CBP will inspect materials, not just the label.
If your product feels like it might be a trap — textiles, footwear, chemicals, anything with moving parts — the cheap insurance is a quick search of CBP's CROSS rulings database for your exact product. Importers of record are held to a "reasonable care" standard, and the presence of a directly relevant ruling is the single best defense if an entry ever gets challenged.
When the 10-digit code decides everything
The 6-digit code gets you in the right chapter; the 10-digit code sets the price. The US HTSUS carries roughly 14,000 ten-digit lines, and the extra digits capture distinctions like fiber content, shoe construction, country eligibility, and whether a product has screens. Two examples from the product guides on this site: a knitted cotton sweater (6110.20.30) versus a knitted man-made-fiber sweater (6110.30.30) differ by several points, and an apparel import line can swing from 14% to 32% on fiber alone. Footwear splits even further — the auto parts and electronics guides show the same pattern at the heading level.
The other thing the 10-digit line carries is exposure. Section 301 lists, anti-dumping orders, and quota or licensing requirements all attach at the 10-digit level. A code that is correct at 6 digits but wrong at 10 can land you in an AD/CVD case you didn't know existed — the anti-dumping guide covers how often that happens. This is also why the code on your invoice should be verified against the current schedule: the US adopted the HS 2022 nomenclature, and the HS 2027 revision takes effect in January 2027, with several chapters renumbering. What was correct last year can quietly stop being correct this year.
When to stop DIY-ing it
You can reliably classify simple, single-material goods yourself — a glass bottle, a steel bracket, a cotton t-shirt. Three situations justify paying for a broker or a classification opinion: goods with a high per-unit value (where one point of duty is real money), goods that combine multiple materials or functions, and goods in categories with active trade remedies (textiles, footwear, steel, solar). A licensed customs broker charges a few hundred dollars per opinion and takes responsibility for the classification in the entry. Compared with a reclassification bill plus interest, it is the cheapest insurance in the import business.
For everything you do classify yourself, keep the reasoning on file: the product description you started from, the headings you compared, and the code you chose. If CBP ever questions an entry, that written trail is what proves you exercised reasonable care — and it is the difference between a corrected entry and a penalty. Once you have the code, run the actual numbers through the import duty calculator and the landed cost calculator before you commit to a price.
Frequently Asked Questions
Can I use the HS code my supplier puts on the invoice?
As a starting point, yes. As your final answer, no. The supplier's code reflects their export declaration, which follows their country's rules — and it is often a simplified or outdated line. Match the description in the US schedule yourself, and if the codes disagree, the US schedule wins for your US entry.
What happens if I use the wrong HS code?
If you underpay duty, customs will reclassify the entry, demand the difference, and in most cases add interest — and if the error looks careless or deliberate rather than accidental, penalties can scale up to the value of the goods. Overpaying has no penalty but is its own quiet tax. The reasonable-care standard means documentation of how you arrived at the code is your best protection.
Do HS codes change?
Yes — the World Customs Organization revises the system roughly every five years, and the next revision (HS 2027) takes effect January 2027. Countries also change their 8- and 10-digit lines between revisions. Re-verify your codes at least annually, and always before a big shipment.
What's the difference between HS, HTS, and a tariff number?
HS is the global 6-digit system. HTS (Harmonized Tariff Schedule) is the US extension to 8/10 digits — the "HTS number" people mean when they ask for an import code. TARIC is the EU's version, and the UK Global Tariff is the UK's. All of them share the first six digits. The glossary on this site defines each term properly in the trade terms glossary.