Classification is where customs broker exams are won or lost. With approximately one-quarter of all questions focused on determining the correct Harmonized Tariff Schedule (HTS) code, mastering classification isn't optional—it's essential.
The good news: classification follows a logical, rule-based system. Once you understand the General Rules of Interpretation (GRIs) and how to navigate Section and Chapter Notes, you can systematically work through any classification question.
This guide covers everything you need to know: the structure of the HTS, all six GRIs with exam-focused examples, the most frequently tested chapters, common mistakes to avoid, and proven strategies for tackling classification questions efficiently.
Understanding HTS Structure
Before diving into classification rules, you need to understand how the Harmonized Tariff Schedule is organized. The HTS code is a 10-digit number that identifies products with increasing specificity.
HTS Organization
| Level | Description | Example |
|---|---|---|
| Sections (I-XXII) | Broad product categories | Section XI: Textiles and Textile Articles |
| Chapters (1-99) | Product groups within sections | Chapter 62: Articles of apparel, not knitted |
| Headings (4-digit) | Specific product categories | 6203: Men's suits, jackets, trousers |
| Subheadings (6-digit) | International harmonized level | 6203.42: Trousers of cotton |
| Statistical suffix (8-10 digit) | U.S.-specific detail | 6203.42.4010: Men's trousers, cotton, not containing 15% or more by weight of down |
Classification always works from general to specific. First determine the correct Section, then Chapter, then 4-digit Heading, then 6-digit Subheading, and finally the full 10-digit code. Trying to jump directly to a 10-digit code without this process leads to errors.
The General Rules of Interpretation (GRIs)
The GRIs are the foundation of all classification decisions. They are six rules that must be applied in order—you only move to the next rule if the previous rule doesn't resolve the classification.
Classification is determined first by the terms of the headings and any relevant Section or Chapter Notes. This is where 90%+ of classifications are resolved.
GRI 1 says: Read the heading. Read the notes. If it fits, that's your classification.
GRI 2(a): Incomplete or unfinished goods are classified as the finished article if they have the essential character of the complete article. Also covers goods presented unassembled or disassembled.
GRI 2(b): Mixtures and combinations of materials are classified as if they consisted of the material or component that gives them their essential character.
When goods appear to be classifiable under two or more headings, apply GRI 3 in order:
GRI 3(a): The heading that provides the most specific description prevails over a more general heading.
GRI 3(b): Composite goods and sets are classified by the component that gives them their essential character.
GRI 3(c): When 3(a) and 3(b) don't resolve it, classify under the heading that occurs last in numerical order.
Goods that cannot be classified under GRI 1-3 are classified under the heading for goods to which they are most akin (most similar).
This is a "fallback" rule rarely needed on the exam.
GRI 5(a): Specially shaped or fitted containers (camera cases, instrument cases, etc.) are classified with the article if normally sold together.
GRI 5(b): Packing materials and containers are classified with the goods unless they're clearly suitable for repetitive use.
Classification at the subheading level (6+ digits) follows the same principles as heading classification. Subheadings at the same level are comparable, and subheading notes apply only within that heading.
Once you've determined the 4-digit heading, use the same logic to drill down to the correct subheading.
A common exam mistake is jumping to GRI 3 or another rule without first attempting GRI 1. The rules must be applied sequentially. Always start with GRI 1 (heading terms and notes). Only if GRI 1 doesn't resolve the classification do you move to GRI 2, and so on.
Section and Chapter Notes
Section and Chapter Notes are legally binding and take precedence in classification. They can include goods in a chapter, exclude goods, define terms, or provide specific classification instructions.
Types of Notes
| Note Type | Function | Example |
|---|---|---|
| Exclusion Notes | States what is NOT covered by a chapter/heading | "This chapter does not cover articles of Chapter 95 (toys)" |
| Inclusion Notes | Specifies what IS covered | "This heading includes parts and accessories" |
| Definition Notes | Defines terms used in the chapter | "For purposes of this chapter, 'stainless steel' means..." |
| Classification Notes | Provides specific classification rules | "Composite articles shall be classified according to..." |
Before looking at heading descriptions, check the Section Notes and Chapter Notes. They often contain exclusions that redirect you to a different chapter, or definitions that clarify how to classify specific products. Missing a note is one of the most common reasons for wrong answers.
Step-by-Step Classification Process
Use this systematic approach for every classification question:
Most Tested HTS Chapters
While questions can come from any chapter, certain chapters appear more frequently on the exam. Focus your study time accordingly:
Special Chapters to Know
- Chapter 98: Special classification provisions (temporary imports, repairs, etc.)
- Chapter 99: Temporary modifications (tariff relief, trade actions)
- Chapter 95: Toys, games, and sports equipment
- Chapter 63: Made-up textile articles (blankets, curtains, etc.)
Exam Strategies for Classification
Common Classification Mistakes
Worked Examples
Let's work through some classification examples using the systematic approach:
Step 1: Key characteristics
- Men's garment
- Woven (not knitted)
- Cotton material
- Trousers (not shorts, not jeans noted)
Step 2: Identify Section/Chapter
Apparel → Section XI (Textiles) → Chapter 62 (Woven apparel) — Note: Chapter 61 is knitted
Step 3: Check Notes
Chapter 62 Notes confirm woven garments are covered. No exclusions apply.
Step 4: Find Heading
6203: Men's or boys' suits, ensembles, jackets, blazers, trousers... ✓
Step 5: Find Subheading
6203.42: Trousers... of cotton ✓
The specific statistical suffix depends on additional details (e.g., whether containing 15%+ by weight of down).
Step 1: Key characteristics
- Automatic data processing machine (computer)
- Portable (laptop, not desktop)
- Has display, keyboard, and storage
Step 2: Identify Section/Chapter
Data processing equipment → Section XVI → Chapter 84 (Machinery)
Step 3: Check Notes
Note 5 to Chapter 84 defines "automatic data processing machines" and their components.
Step 4: Find Heading
8471: Automatic data processing machines and units thereof ✓
Step 5: Find Subheading
8471.30: Portable automatic data processing machines, weighing not more than 10 kg, consisting of at least a central processing unit, a keyboard and a display ✓
Portable ADP machines (laptops).
Step 1: Key characteristics
- Multiple products packaged together
- Components: perfume, deodorant, after-shave
- Eau de toilette is highest value component
Step 2: Identify Section/Chapter
Perfumes/cosmetics → Section VI → Chapter 33 (Essential oils, perfumery, cosmetics)
Step 3: This is a set—Apply GRI 3(b)
When goods are sets for retail sale, classify by the component that gives essential character. The eau de toilette ($45) is the dominant value/purpose.
Step 4: Find Heading
3303: Perfumes and toilet waters ✓
Classified as perfume/toilet water based on GRI 3(b)—the component giving essential character to the set.
How to Practice Classification
Classification is a skill that improves with practice. Here's how to build proficiency:
Daily Practice Routine
- Start with 5-10 classification problems daily during your study period
- Use past exam questions—they show the exact format and difficulty level
- Time yourself—aim for 3-4 minutes per question maximum
- Review every wrong answer—understand exactly why you missed it
- Practice HTS navigation—finding sections quickly is as important as knowing the rules
Progressive Difficulty
| Study Phase | Focus | Example Topics |
|---|---|---|
| Weeks 1-4 | Learn GRIs, practice simple classifications | Single-material products, clear categories |
| Weeks 5-8 | Add complexity—mixtures, sets, parts | Mixed materials, composite articles, GRI 2-3 |
| Weeks 9-12 | Full exam-style questions under time pressure | All question types, timed practice |
| Final weeks | Practice exams with mixed topics | Full-length exams simulating real conditions |
You're ready when you can:
- Recite the 6 GRIs and explain when each applies
- Navigate to any HTS Section/Chapter in under 30 seconds
- Consistently score 80%+ on classification practice questions
- Complete classification questions in 3-4 minutes each
- Identify when notes redirect classification to a different chapter
Frequently Asked Questions
Classification questions make up approximately 20-25% of the exam—typically 16-20 questions out of 80. This makes it the single most heavily weighted topic, so mastering classification is essential for passing.
The GRIs are six rules that govern HTS classification, applied in order: GRI 1 (heading terms and notes), GRI 2 (incomplete goods and mixtures), GRI 3 (multiple possible headings), GRI 4 (most similar goods), GRI 5 (containers and packing), and GRI 6 (subheading classification). Most classifications are resolved at GRI 1.
The most frequently tested chapters include: Chapters 61-62 (apparel), Chapters 84-85 (machinery and electrical), Chapters 39-40 (plastics and rubber), Chapters 72-73 (iron and steel), Chapter 94 (furniture), and Chapter 87 (vehicles). However, questions can come from any chapter.
Use this systematic approach: (1) Read the product description carefully and identify key characteristics, (2) Determine the likely Section and Chapter, (3) Read Section and Chapter Notes first, (4) Apply GRI 1 to find the correct heading, (5) Work down to the subheading level using GRI 6, and (6) Verify your answer makes logical sense.
Aim for 3-4 minutes per classification question. If you're spending more than 5 minutes, mark the question and move on—you can return to it later. With 80 questions and 270 minutes total, you can't afford to get stuck on any single question.
No. The exam is open-book, and you'll have the HTS available. What you do need is the ability to navigate quickly to the right section and apply classification rules correctly. Memorizing the structure and frequently tested chapters helps, but not specific codes.
The most common mistake is skipping the Section and Chapter Notes. Notes often contain exclusions that redirect classification to a different chapter, or definitions that change how you interpret heading terms. Always read the notes before looking at heading descriptions.
Practice Classification Questions
Put your knowledge to the test with our classification practice problems.