How to Classify Goods Under the Harmonized System: A Method

How the code is built, digit by digit

The Harmonized System is maintained by the World Customs Organization and used by the large majority of trading economies. Its structure is the reason classification is learnable rather than arbitrary.

• **Digits 1–2: the chapter.** Broad material or product family. Chapter 39 is plastics and articles of plastic, Chapter 21 is miscellaneous edible preparations, Chapter 33 is essential oils and cosmetic preparations.
• **Digits 3–4: the heading.** A narrower description within that chapter.
• **Digits 5–6: the subheading.** The most specific level that is identical worldwide. Six digits is where international agreement stops.
• **Digits 7 onwards: national detail.** Each country adds its own digits for tariff and statistical purposes, which is why a code can be eight, ten or eleven digits depending on where you are importing.

Two consequences follow. First, a six-digit code quoted by your supplier is a starting point, not a declaration — you still need the national extension for your own country. Second, the same product can legitimately carry different full-length codes in Thailand and in your market, and that is not a sign anyone made a mistake.

The HS is also revised periodically, so a code copied from an old file may no longer exist. Always work from your country's current tariff schedule rather than from last year's packing list.

The General Rules of Interpretation, in plain language

Classification is not a free judgement call. Six General Rules of Interpretation sit at the front of the tariff, and they apply in order. You may not jump to a later rule while an earlier one still resolves the question.

**Rule 1 — the texts govern.** Classify according to the wording of the headings and the legal notes to the chapters and sections. Those notes are binding, not commentary, and they are where most arguments are actually settled.

**Rule 2 — incomplete and unassembled goods.** An unfinished article that already has the essential character of the finished one is classified as the finished article. A product shipped knocked-down is classified as if assembled.

**Rule 3 — when two headings both seem to fit.** Apply in sequence: the more specific description wins; if that does not settle it, classify by the material or component that gives the goods their essential character; if that still does not settle it, take the last heading in numerical order among those equally applicable.

**Rule 4 — goods most akin.** A fallback for genuinely novel products.

**Rule 5 — packing and containers.** Covers cases, boxes and similar containers presented with the goods.

**Rule 6 — subheadings.** The same logic applies one level down, comparing only subheadings at the same level.

Write down which rule carried your decision. Half the value of classification work is being able to explain it later.

A workflow you can repeat for every new product

Treat each product as a short file rather than a guess. The steps below take minutes once you have done them a few times.

1. **Describe the thing, not the brand.** What is it made of, what does it do, how is it presented for retail, what is its fill or size? Marketing language is useless here; composition and function are everything. 2. **Get a technical sheet and an ingredient or material breakdown** from the supplier, with percentages where composition matters. When you request quotes from Thai suppliers, ask for this in the same message — it is far harder to obtain after the deposit is paid. 3. **Shortlist two or three candidate chapters** and read the section and chapter notes for each, including the exclusions. Exclusions eliminate more candidates than inclusions confirm. 4. **Narrow to headings, then subheadings**, applying the General Rules in order. 5. **Add your national digits** from your own country's current tariff schedule. 6. **Check what the code triggers**: duty rate, import taxes, permits, licences, inspection regimes, labelling obligations. 7. **Check preferential eligibility** and the origin documentation it requires. 8. **File the reasoning** — the rule you relied on, the notes you read, the technical sheet, and the date.

One discipline worth adopting: classify before you negotiate volume. A code that carries a permit requirement can change which product you want to order at all.

Worked examples from common Thai sourcing categories

The method is easier to see on real goods.

**Plastic kitchen storage boxes.** Composition is clear, so the plastics chapter is the natural starting point and the relevant heading covers tableware, kitchenware and household articles of plastic. The question that usually remains is the subheading split by article type. Where buyers go wrong with Thai household products is mixing many unrelated items under one code because they arrived in one carton — classification follows each article, not the shipment.

**Seaweed snacks and fruit crisps.** Here the chapter depends on composition and processing: a simple dried fruit, a roasted seasoned sheet and a flour-based fried snack can fall in different chapters. For Thai snacks wholesale orders, get a per-SKU ingredient and process description; the word snack has no tariff meaning.

**Capsules, powders and functional drinks.** This is the category that generates the most disputes. Food supplements presented in measured doses are commonly handled as food preparations, while products with a therapeutic or prophylactic purpose may belong in the pharmaceutical chapter, and the border between the two is drawn differently in different markets. If you import Thai health supplements, assume the classification needs confirmation in writing rather than inference.

**Balms and massage oils.** Again a split between cosmetic preparations and medicaments, decided by composition, presentation and claims. Note the loop: the claims on your own label can affect your own classification.

Rulings, documentation and who is actually liable

When money or risk is material, do not rely on an internet search or a supplier's opinion.

Most customs administrations offer an advance or binding ruling: you submit a full product description, often with samples and technical data, and receive a written classification decision you can rely on for future entries. It takes time and effort to prepare, which is exactly why it is worth doing for your core SKUs rather than for one-off purchases. A licensed customs broker can prepare the application and tell you what evidence your authority expects.

Understand the liability split. In most jurisdictions the importer of record is responsible for the accuracy of the declaration, even when a broker keyed it and even when the supplier supplied the code. A misdeclaration can mean back duty, interest, penalties, loss of preferential treatment and, for repeat findings, closer scrutiny of everything you bring in. Rules, rates and procedures differ by country and change, so treat this article as reference and confirm your specific case with your own customs authority or a licensed broker.

Keep a classification register: product, code, the rule relied on, supporting documents, the date, and who approved it. When an officer asks three years later, that file is the difference between a conversation and a reassessment.

Mistakes that quietly cost the most

Six patterns show up again and again, and none of them look like errors at the time.

• **Copying the supplier's code without checking.** Exporters classify for export in their own country. The six digits may be right, the national extension almost certainly is not yours.
• **One code for a mixed shipment.** Convenient, and a reliable way to invite an examination. Each article is classified on its own facts.
• **Classifying from the marketing name.** Herbal relief balm, premium wellness drink and natural cleaner are not tariff descriptions. Composition and function are.
• **Ignoring the notes.** The General Rules point you to the legal notes first for a reason. Skipping them is the single most common source of a wrong answer that feels right.
• **Letting labels and classification drift apart.** Add a therapeutic claim to your packaging and you may have changed the product's category without touching the formula.
• **Freezing a code forever.** Tariff schedules are periodically updated and your product specification may also change. Re-verify your main codes on a schedule, not only when something goes wrong.

A practical next step: pick your top SKUs by value, build a one-page classification file for each, and have a broker review them before your next shipment leaves.