How to find the HS code for your product

Every product that crosses a US border needs a classification number before it can clear customs. Get it right and duty is calculated correctly, the entry clears cleanly, and nobody comes asking questions later. Get it wrong and one of two things happens: you overpay for years without ever noticing, or you underpay and expose the business to back-duties, interest and penalties once CBP catches the error during an audit. This guide is the complete method — how the schedule is structured, where to actually search for a code, how to work from the six-digit international root down to the ten-digit US line, and the specific mistakes that quietly cost importers real money.

None of this is exotic. Classification is a rules-based exercise, and once you understand the structure, most products settle into an obvious heading within a few minutes. The ones that don't — composite goods, kits, anything with more than one plausible material or function — are exactly where this guide spends the most time, because that's where the money is actually won or lost.

What an HS code actually is

The Harmonized System (HS) is a global product-naming standard maintained by the World Customs Organization. The first six digits are identical in every one of the 200-plus countries that use it, so 6109.10 means the same thing whether the shipment is landing in Los Angeles, Rotterdam or Ho Chi Minh City. The United States then adds four more digits of its own statistical detail to create the 10-digit Harmonized Tariff Schedule (HTS) number that CBP actually charges duty against.

• First 2 digits = the chapter (e.g. 61 = knitted apparel).
• First 4 digits = the heading (e.g. 6109 = T-shirts and singlets).
• First 6 digits = the international HS subheading (e.g. 6109.10 = of cotton).
• Digits 7–10 = the US statistical suffix (e.g. 6109.10.0060 = men's/boys' cotton tees).

People use "HS code", "HTS code", "harmonized tariff code" and "tariff classification" fairly interchangeably in everyday conversation, and that's usually harmless — but the two numbers are legally different things. The HS code is the shared six-digit root. The HTS code is what the US bolts on top: four extra digits that exist only in the US schedule and that nowhere else in the world uses. When a freight forwarder or a broker asks for "the harmonized tariff code" on a shipment clearing at LAX, they mean the full ten-digit HTS number, not the six-digit HS root a supplier might have sent you on a packing list.

Where do you actually look up an HTS code?

The official, free source for a US HTS lookup is the USITC's Harmonized Tariff Schedule search tool — it holds the current schedule of record, including every general rate, every Chapter 99 modifier, and the legal text of every chapter and section note. Type in a keyword or a candidate heading and it returns the full list of ten-digit lines underneath it, with the general (Column 1) duty rate next to each one. That's the number you check before you file, not a spreadsheet a colleague built two years ago.

A second official tool worth knowing: CBP's CROSS database of binding rulings. If another importer has already asked CBP to classify something similar to your product, the ruling is public and searchable, and it shows the legal reasoning CBP used — which heading it chose and why. Reading two or three rulings on comparable goods before you commit to a code is one of the fastest ways to sanity-check a classification without paying a broker for a first opinion.

Step 1 — describe the product the way the schedule does

Customs classification is about what a thing is, what it is made of, and what it does — not what you call it in your catalogue. Before you search anything, write a one-line technical description: the material (cotton, stainless steel, ABS plastic), the form (knitted, cast, assembled), the function, and who uses it. "Cozy weekend tee" is a marketing name; "men's knitted T-shirt, 100% cotton" is a classification. If the product has more than one material or component, note that too — the split often decides which of two headings you end up in.

Step 2 — find the chapter, then the heading

Start broad. The 99 chapters of the schedule are grouped by material and then by degree of manufacture — raw materials early, finished goods later. Narrow to the chapter, then read the heading texts inside it word by word. Headings are legal descriptions, not casual labels, so read them literally. If a heading says "knitted or crocheted," a woven version of the same garment belongs somewhere else entirely, even though it looks identical on a hanger.

Step 3 — apply the General Rules of Interpretation

When more than one heading looks plausible, the six General Rules of Interpretation (GRI) decide, in strict order. GRI 1 says the heading text plus the section and chapter notes govern above everything else — read those notes, because they frequently include or exclude things you'd never expect from the heading alone. GRI 3 handles goods that could genuinely sit under two headings: classify first by whichever heading gives the most specific description, then by essential character if that doesn't resolve it, then by the last heading in numerical order as a final tie-breaker.

Essential character is easiest to see with an example. A boxed gift set containing a cordless drill and a case of interchangeable screwdriver bits could arguably be classified under either component. GRI 3(b) says look at what gives the set its essential character — here, that's clearly the drill, since the bits are supporting accessories to it, not the reason someone buys the set. The whole set is classified under the drill's heading, and the bits ride along on it rather than being broken out separately. Most real-world classification disputes are resolved by GRI 1 and GRI 3 alone; the remaining four rules cover edge cases you'll rarely meet.

Step 4 — read the notes and check for exclusions

Section and chapter notes are binding law, not commentary — they carry exactly the same legal weight as the heading text itself. A chapter note can pull a product out of the obvious heading and send it to a completely different chapter: parts of general use, sets, composite goods and "articles of plastic" are the most common traps. If a note excludes your product from a heading, believe the note, even if the heading text on its own would have seemed to fit perfectly.

Step 5 — confirm the rate on the official schedule

Once you have a candidate 10-digit line, verify the duty rate against the USITC Harmonized Tariff Schedule — the schedule of record. Never trust a rate you saw in a forum post, an old spreadsheet, or generated by an AI tool without a source attached. And remember: the base MFN (most-favoured-nation, i.e. the standard Column 1) rate is rarely the whole bill. Section 301, Section 232 and other Chapter 99 measures stack on top of the base rate depending on the country of origin, and those additional layers move far more often than the base schedule does.

• Read the general (Column 1) rate for normal-trade-relations countries.
• Check Chapter 99 for additional Section 301 / 232 duties tied to country of origin.
• Note the unit of quantity — some lines carry specific ($/kg) or compound rates rather than a simple percentage.
• Screen for antidumping/countervailing duty orders, which can dwarf the base rate on some products.

How to read a duty rate once you've found it

The HTS lists rates in four basic formats, and it's worth being able to read all four on sight, because a rate that looks small in one format can be the largest line item on the entry.

Chapter 99 is where the additional, origin-driven duties live — Section 301 tariffs on Chinese-origin goods, Section 232 on steel and aluminium content, and the various reciprocal-tariff modifier codes that have been added to the schedule since. These sit on a separate line from the base HTS classification and get added at the entry-summary stage, but they're calculated against the classification you settled on in Steps 1 through 4 — get the base line wrong and the Chapter 99 layer stacks on top of the wrong number too.

What's the difference between an HS code and a tariff classification, in practice?

In casual use, none — "HS code," "tariff classification" and "commodity code" all point at the same underlying exercise of matching a physical product to a line in the schedule. The distinction that actually matters is depth. An HS code, strictly speaking, is the six-digit international figure. A tariff classification, for US import purposes, means the full ten-digit HTS line plus any applicable Chapter 99 modifier. If a customs broker asks for your product's tariff classification and you hand over six digits, expect a follow-up question — six digits identify the product family, but they can't tell CBP's system which specific statistical line, and therefore which specific rate, applies.

Common mistakes that cost real money

A five-person homeware brand shipping rattan dining chairs from Vietnam classified them under a generic "furniture parts" line for two years, based on a code the factory had put on the commercial invoice. When a broker reviewed a sample entry ahead of a bigger order, the chairs turned out to belong under a different heading entirely — one with a materially lower general rate. The business had been overpaying by roughly $14,000 a year without any way of knowing it, because nothing in the entry process flags an importer who's simply paying too much.

• Classifying by brand or use-case name instead of material and construction.
• Stopping at 6 digits — the US rate lives on the 10-digit line, not the international root.
• Ignoring chapter notes that exclude your product from the obvious heading.
• Forgetting that origin, not where you bought it, drives the additional Chapter 99 tariffs.
• Reusing a supplier's code without checking it against the current schedule.
• Assuming last year's rate still applies — Chapter 99 measures in particular change often.

Most classification disputes I see aren't exotic edge cases — they're someone reading the product name instead of the heading text, or stopping at six digits because that's what the supplier put on the invoice. The schedule rewards people who actually read the notes.

Do you need a customs broker to classify your product?

For a straightforward finished good — a single material, a single obvious function, no unusual assembly — this five-step method gets you to the right line yourself, most of the time. For sets, kits, multi-material assemblies, chemicals, or anything where a wrong guess is expensive at volume, a licensed customs broker or a formal CBP binding ruling is worth the fee. Nothing in this guide, and nothing PortRobin returns, is a customs ruling. It's an informational estimate designed to get you to the right answer faster and to make your conversation with a broker shorter and cheaper, not to replace one when the stakes genuinely call for it.