Every product crossing a border is classified under the Harmonized System, maintained by the World Customs Organization. The code decides the duty rate, which rules apply, and which statistics the shipment counts toward.
How the code is built
- Chapter (2 digits): the broad family, such as 72 for iron and steel or 10 for cereals.
- Heading (4 digits): a product group, such as 7214 for bars and rods of iron or non-alloy steel.
- Subheading (6 digits): the internationally harmonised level, used by most countries.
- National digits (8 to 10): added by each country for its own tariff and statistics. These differ between markets.
Why it matters
The same product can carry very different duties depending on classification. Regulatory requirements, such as conformity certificates or import licences, are often linked to specific codes. Misclassification can lead to delays, penalties or retrospective duty claims.
How to get it right
Start from the product’s material and function, then read the chapter and heading notes. Where a product could fit more than one heading, the General Interpretative Rules decide. For valuable or regular trades, many customs authorities offer binding tariff rulings.
Use the same code on every document
The commercial invoice, packing list and customs declaration should carry consistent codes. TP4 product guides show the four-digit heading for each product as a starting point; always confirm the full code for your exact product and destination.
General information, not legal, tax or financial advice. Updated October 2026.