1. The official sources
World Customs Organization
The HS nomenclature itself: the headings, subheadings, section and chapter notes, and the General Interpretative Rules.
The WCO’s nomenclature is the legal basis, and the notes are binding.
China Customs
The Import and Export Tariff of the People’s Republic of China issues annually, with the ten-digit schedule, duty rates and regulatory categories.
Customs publishes classification decisions and rulings.
The destination’s tariff schedule
The EU’s Combined Nomenclature and TARIC.
The United States’ Harmonized Tariff Schedule.
Each member’s national schedule.
2. The national tariff schedules as primary sources
For a given import, the destination’s national schedule is the authoritative source.
It contains the ten-digit codes, the duty rates, the regulatory requirements and, importantly, the additional national notes that qualify classification.
3. The classification decisions database
Most major customs authorities publish their classification decisions.
China Customs publishes rulings.
The EU publishes its classification regulations and the TARIC measures.
The United States publishes CBP rulings searchable through CROSS.
The WCO publishes a classification opinions compendium.
These are the most useful practical source, because they show how the authority has actually classified comparable goods.
4. The explanatory notes
The WCO’s Explanatory Notes elaborate on the headings and are not legally binding but are persuasive.
The Compendium of Classification Opinions records the WCO’s decisions on specific goods.
Used together, they resolve most uncertainty.
5. What is not an authoritative source
Supplier-provided codes
Often wrong, and the supplier has no incentive to be precise.
Freight forwarder databases
Useful starting points, not authoritative.
Search engines and general websites
Frequently outdated, and rarely show the notes.
Another company’s declaration
The classification may be wrong, and it is not a defence to say another importer used the code.
6. The lookup process
Start with the product’s function and composition.
Use the chapter and section notes to eliminate chapters.
Use the heading text and GIR 1.
Where ambiguous, apply the remaining GIRs in order.
Check the destination’s national schedule for the subdivisions and any national notes.
Where doubt remains, consult the classification decisions for comparable goods.
7. The documentation
Record the classification and the reasoning.
This matters because a post-clearance audit asks why the code was chosen, and an answer of “the supplier told us” is weak.
A record showing which headings were considered, which notes applied, and which GIR resolved it is a defensible classification.
8. The advance ruling
Where the classification is material and uncertain, an advance ruling settles it.
The rulings databases show what the authority has decided on comparable goods, which is often enough without a formal application.
9. Closing view
The authoritative sources are public and free, and they are used less than the informal ones.
That is the practical gap: most classification errors are traceable to a supplier’s code or a forwarder’s database rather than to the tariff schedule.
*This article is based on the Harmonized Commodity Description and Coding System and national tariff schedules published by the World Customs Organization and national customs authorities. Traders should confirm classification with the relevant customs authority.*