The General Rules of Interpretation are six legally binding rules, printed at the front of the HTSUS, that govern how every imported product gets classified. They are a mandatory sequence, not a menu: GRI 1 is evaluated first, always, and every later rule may only be invoked once the classifier has established that every prior rule genuinely failed. GRI 1 classifies by the heading terms and the section and chapter notes, and it resolves over 90 percent of products. GRI 2 covers unfinished articles and mixtures. GRI 3 breaks ties between two or more headings. GRI 4 is the residual rule. GRI 5 handles packaging. GRI 6 repeats the exercise at the subheading level.
GRI 1 resolves most goods, and most importers skip it
GRI 1 says to classify according to the terms of the headings and any relevant section or chapter notes. The chapter and section titles printed above the headings are for reference only and carry no legal weight. What governs is the heading text itself, read together with whatever section or chapter notes apply, and those notes carry the same legal force as the heading text, not some lesser status. A product explicitly named in a heading goes there, and most goods are resolved here, which is why the discipline of working GRI 1 first, reading the headings and the legal notes before reaching for essential character, is what separates a defensible classification from a convenient one.
The recurring mistake is to start with the keyword that sounds closest and work backward. Classification is not a search for the closest-sounding description. It is a legal determination, and the importer, not the customs broker and not CBP, is legally responsible for getting it right under the duty of reasonable care. The HS is revised on a roughly five-year cycle, with the 2022 edition current, so codes move over time, and a classification that was right last year may not be right this year. Re-verify the code rather than assuming it still applies.
Related reading on this site: TariffTrack HQ and Tariff Engineering: When a Design Change Legitimately Changes the Duty Rate cover the neighbouring problems in more depth.
GRI 2 and GRI 3 are where the real fights happen
GRI 2 closes two loopholes. GRI 2(a) says an unfinished or unassembled article classifies as the finished article, as long as it already has the finished article's essential character, so shipping a product in pieces does not change its classification. GRI 2(b) says a heading that names a material also covers mixtures or combinations of that material, so a stainless-steel mug with a plastic handle may still classify with stainless steel mugs. But GRI 2(b) also opens the door to GRI 3, because when the mixing begins to deprive the article of its essential character, or makes it classifiable equally well under multiple headings, the tie has to be broken.
GRI 3 only gets reached when a product is genuinely, prima facie classifiable under two or more headings, and it breaks the tie in three steps. GRI 3(a) says the most specific description wins. If the headings are equally specific, GRI 3(b) says the component that gives the goods their essential character governs, which covers composite goods, mixtures, and sets put up for retail sale. If that still does not resolve it, GRI 3(c) says the heading that occurs last in numerical order controls. Essential character has no formula: nature, bulk, quantity, weight, value, and functional role are all relevant, and none of them is automatically decisive, which is why classification disputes over composite goods are argued like the litigated disputes they are.
When the rules run out, and how to get certainty
GRI 4 is the residual rule, for the product nothing else describes: it classifies by the goods it is most akin to. GRI 5 handles cases and packaging, and GRI 6 repeats the whole exercise one level down, at the subheading, applying GRI 1 through 5 to select the correct subheading within the already-determined heading. The sequence matters at every level, and a classifier cannot invoke GRI 3 because a product feels complicated. They have to first show that GRI 1 and GRI 2 were genuinely insufficient, and the record of that showing is what survives an audit.
For certainty, the tools are public. CBP issues binding rulings under 19 CFR Part 177, requested through the eRulings portal with a description of the product, and a binding ruling is legally binding on the agency at every port. Past rulings are searchable in CBP's public CROSS database at rulings.cbp.gov, which holds hundreds of thousands of published rulings and is the best starting point for researching how CBP has treated similar goods. An importer who files with a binding ruling in hand has a classification that no port can second-guess. An importer who files on a keyword search has a classification that any port can.
Frequently asked questions
What are the General Rules of Interpretation?
They are six legally binding rules, printed at the front of the HTSUS, that govern how every imported product gets classified. They must be applied in strict sequence, and GRI 1 is evaluated first, always.
How many products does GRI 1 resolve?
Over 90 percent. GRI 1 classifies by the terms of the headings and the section and chapter notes, and most goods are resolved there without ever reaching the later rules.
What is essential character under GRI 3?
It is the test for deciding which component gives a composite good, mixture, or retail set its classification identity. Nature, bulk, quantity, weight, value, and functional role are all relevant, and none of them is automatically decisive.
How do I get a binding classification from CBP?
Request a binding ruling through CBP's eRulings portal under 19 CFR Part 177, describing the product. The ruling is legally binding on the agency at every port. Past rulings are searchable in the CROSS database at rulings.cbp.gov.