General Interpretive Rules
The six rules that decide every classification, in the order you have to apply them, with the mistake each one catches.
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Six rules decide every HS classification, and you apply them in order. Most goods stop at Rule 1, and every later rule is only there for what Rule 1 can't settle. If you're writing a justification that starts with "essential character" and you haven't read the heading text and notes, you've started in the wrong place.
The rules are short and are published by the WCO. The US tariff calls them the GRIs, others the General Rules, and some national tariffs add their own further rules.
The rules, and what each one is for
| 1 | Classify by heading text and Section or Chapter Notes. Titles are for reference only | Picking a chapter from its title |
|---|---|---|
| 2(a) | A heading for an article includes it incomplete, unfinished or unassembled, if it has the essential character of the finished one | Treating a flat-pack or a kit as "parts" |
| 2(b) | A heading for a material includes mixtures and goods partly of it, and sends you to Rule 3 | Assuming a small amount of another material changes nothing |
| 3(a) | With two or more candidate headings, the most specific wins. If each describes only part of the goods, they count as equal | Picking the broader heading because it's familiar |
| 3(b) | Mixtures, composites and retail sets go by the component giving essential character | Stopping at value alone |
| 3(c) | If it's still a tie, take the heading that comes last numerically | Using this first because it's easy |
| 4 | Goods that fit nowhere go with what they're most akin to | Almost never needed, so if you're using it, look again |
| 5 | Specially fitted cases, and normal packing, go with the goods | Declaring the case or crate separately |
| 6 | Repeat the logic at subheading level, comparing only subheadings at the same level | Comparing a one-dash line with a two-dash line |
Rule 1 does nearly all the work
The titles don't count. CBSA's own illustration is revolvers: they're articles of base metal, but they belong in Section XIX with arms and ammunition. Notes can pull goods in or push them out regardless of how well a heading seems to fit. So read the notes for the section and the chapter before you read the heading list. A note that says "this chapter does not cover" ends the discussion.
One worked classification
This is our own illustration of the logic, not a ruling on a real product. Take a retail pack of a stainless steel flask and a padded canvas carrying sleeve, sold together.
- Rule 1. Candidate headings for the flask and the sleeve are in different chapters, and neither heading covers both. So Rule 1 alone doesn't settle it.
- Rule 5(a). A specially shaped case made for long-term use and sold with the article goes with it, unless the case itself gives the whole its character. A fitted sleeve is a strong candidate. If it applies, you classify the flask and the sleeve follows.
- If the sleeve isn't fitted, you ask whether it's a set for retail sale. That's Rule 3(b), and bundles, kits and sets covers the test.
- Rule 6. Once the heading is fixed, work down the subheadings one level at a time, comparing like with like.
Essential character is a judgement you must be able to explain
Rule 3(b) asks which component makes the goods what they are. Authorities look at nature, bulk, quantity, weight, value and the role in use. No single factor decides it. So a low-value component can still give the character, and a high-value one might not.
CBSA's example of a cutting board with a small stone section shows Rule 2(b) leading to Rule 3. Its pillow in the shape of a toy horse shows Rule 3(c): when neither pillow nor toy gives the character, the later heading wins, and that's 95.03.
Write your reasoning down when you classify. If you're ever asked, a note that says "essential character: the sleeve is 8% of value, 12% of weight, and it doesn't affect how the flask is used" is far better than a code with no reasoning behind it.
Where the rules stop
The rules govern the six digits and, in most tariffs, the national digits too, with the WCO's Explanatory Notes as the main guide on how to read them. They don't tell you the duty rate or the origin. For national-level rulings you can rely on, see HS codes. And to get a first candidate code from a description, use the HS code classifier, then test it against these rules.
Frequently asked questions
Does the US apply the same rules?
Yes. The HTS uses the same six GRIs, plus its own additional US rules of interpretation, and CBP walks through both in its tariff classification publication.
What happens if two authorities disagree?
Each country decides for its own tariff. You can hold a ruling in one and get a different treatment in another. The WCO can issue classification opinions, but your binding answer comes from the destination's authority.
Sources
- WCO: General Rules for the Interpretation of the Harmonized System, checked 5 November 2026
- CBSA: Guide to tariff classification, the general rules, checked 5 November 2026
- WCO: HS Nomenclature 2022 edition, sections and chapters, checked 5 November 2026
- CBP: Tariff Classification, an informed compliance publication, checked 5 November 2026