What HS Codes Are
The Harmonized System (HS) is a global product-classification code system used by customs authorities worldwide. Every traded product has a 6-digit global HS code; most countries extend it to 8-10 digits for national tariffs.
Example (US):
- HS 6 digit: 6109.10 (T-shirts, singlets of cotton)
- HTS 10-digit (US): 6109.10.0050 (specific duty rate applies)
Why It Matters
Duty rate
The HS / HTS code determines the duty rate. A misclassified product could be subject to 2% duty when the correct code is 25%, or vice versa. Getting caught means back-duties + penalties.
Entry requirements
Some codes require special permits (FDA for food, FCC for electronics, CPSC for kids' products).
Anti-dumping duties
Specific codes are subject to anti-dumping duties that can reach 100-400%. Misclassifying around ADDs is a serious customs violation.
Section 301 tariffs
US-China tariffs depend on HTS code. The same product can face 7.5% or 25% depending on list and code.
How to Classify
Step 1: Read the section / chapter notes
HS codes are grouped into 21 sections and 99 chapters. Each section has explanatory notes that define scope. Section and chapter notes are binding legal text.
Step 2: Apply the General Rules of Interpretation (GRI)
There are 6 GRI rules:
- Terms of headings + section/chapter notes control classification
- Incomplete / unassembled = classified as the finished article
- When goods fit multiple headings, use: (a) specific over general; (b) essential character; (c) last heading
- If still ambiguous, classify with the most similar goods
- Cases and packaging
- Same rules apply within subheadings
Step 3: Check national supplementary rules
Countries add their own sub-codes (HTS-US, TARIC-EU, etc.). Sub-code determines actual duty.
Common Misclassification Mistakes
Classifying by name, not characteristics
"Smart watch" could be classified under watches (9101), video playback (8519), or telecom (8517) depending on primary function. Customs cares about what it does, not what it's called.
Parts vs finished goods
A complete unassembled product (e.g., DIY kit) is usually classified as the finished product. Loose parts shipped together can still trigger "article" classification.
Composite goods
Items made of multiple materials (cotton + poly blend shirt) classify by dominant material. Get material percentages before classifying.
Sets
Items sold together (e.g., knife set with case) classify based on essential character.
Tools for Classification
Free
- USITC Harmonized Tariff Schedule (hts.usitc.gov) for US
- TARIC database for EU
- Hong Kong Trade & Industry Department HS finder
Paid
- Descartes Datamyne
- Flexport Classification Tool
- SAP GTS (enterprise)
AI-assisted
Some customs brokers now use LLMs to suggest initial classifications. Always verify.
When to Get Professional Help
Binding rulings
US CBP and EU customs offer binding rulings — you describe the product, they classify it, rulings are enforceable for 3 years. Strong protection for new products.
Licensed customs brokers
Fee $200-500 per classification. Worth it for high-volume or unusual products.
Audit Risk
Post-entry audit
Customs can audit past entries 5 years back. Misclassification caught retroactively means duties + interest + penalties.
Red flag triggers
- Unusually low duty rate for the product description
- Sudden changes in HS code used for same supplier / product
- Inconsistent HS codes across same-product entries
Key Takeaways
- HS code determines duty rate and entry requirements
- Use GRI rules in order to classify
- Classify by product characteristics, not marketing name
- Get a binding ruling for high-stakes new products
- Misclassification = back-duties + penalties, up to 5 years after
See also [/glossary/hts-code](/glossary/hts-code), [/guides/understanding-incoterms-fob-cif-ddp](/guides/understanding-incoterms-fob-cif-ddp).