HTS Code Structure: How to Read the 10 Digits
Updated 2026-07-17 · Target term: “hts code meaning”
A 10-digit HTS code breaks into five 2-digit pairs: chapter, heading, subheading (together the 6-digit international HS code), then a US tariff-rate line and a statistical suffix. Read left to right the code goes from broad to specific. Take 8471.30.01.00: 84 is the chapter, 8471 the heading, 8471.30 the international subheading, 8471.30.01 the US legal rate line, and the final 00 the statistical suffix.
The five pairs
- 84 — Chapter: broad category (here, machinery and mechanical appliances)
- 8471 — Heading: the product family (automatic data-processing machines)
- 8471.30 — Subheading: the full 6-digit HS code, identical worldwide
- 8471.30.01 — US rate line (digits 7–8): sets the legal duty rate
- 8471.30.01.00 — Statistical suffix (digits 9–10): for Census trade data
Why the first six digits matter most
Those six digits are the shared language of global trade — the same in every HS country. Everything OpenTariff cross-references between countries keys off the 6-digit root. Compare, say, 8517.13 smartphones and its cross-country siblings shown on that page.
Why the last four digits decide your money
The 6-digit code cannot give you a US duty rate — the rate lives on the 8-digit line, and trade remedies attach there or at the 10-digit level. This is exactly where free tools go wrong: they show the MFN base but miss the Section 301 or 122 lines that stack on top. See how the stack is built in How to check a Section 301 list.
Reading a duty stack
On a US code detail page each line shows its rate, its legal basis, its source link and its effective date — MFN base, then any Section 301 list, any Section 232 steel/aluminium hit, and the Section 122 global surcharge where it applies. The receipt-style breakdown is the whole point: you can trace every percentage point. Open any product page, e.g. HS code for a GaN charger, to see it.
Worked example: reading 6109.10.00.10
Take a cotton knitted T-shirt. 61 is the chapter (articles of apparel, knitted or crocheted). 6109 is the heading (T-shirts, singlets and other vests, knitted). 6109.10 is the international subheading (of cotton) — that is the code a factory in another country would also use. The US then adds .00 as the rate line and a statistical suffix such as .10 for men's or boys'. Swap the fabric to woven and you leave chapter 61 entirely for chapter 62 — see HS code for a men's dress shirt versus HS code for a cotton T-shirt.
Sections, chapters and the notes that bind them
The schedule is grouped into 21 sections and 99 chapters. Chapter 77 is reserved, and chapters 98–99 hold US-specific special provisions — Chapter 99 is where the Section 301, 232 and 122 measures live as additional headings that cross-reference the normal code. That is why a duty can attach "on top" of your base classification: the Chapter 99 heading points back at your Chapter 84 or 85 code. The legal section and chapter notes override loose intuition, so always read them before finalising.
Column 1 vs Column 2 rates
US tariff pages show two general columns. Column 1 (General) is the normal-trade-relations / MFN rate that applies to most countries, and it also has a Special sub-column for FTA and preference-program rates. Column 2 is the much higher rate reserved for a small number of countries without normal trade relations. Almost every commercial import you classify reads from Column 1, then adds any Chapter 99 measures. OpenTariff shows the Column 1 base plus each stacked measure as its own line.
A subtlety worth internalising: the duty unit is not always a percentage. Most consumer goods carry an ad-valorem rate (a percent of value), but some lines are specific (a fixed amount per kilogram, litre or unit) or compound (both). When you read a rate line, check the unit before you multiply — a specific rate of a few cents per unit behaves very differently from an ad-valorem rate as your unit value moves. The statistical suffix at digits 9–10, meanwhile, never changes the money; it exists purely so the Census Bureau can count trade at a finer grain than the legal rate line requires. Two products with the same 8-digit rate line and different statistical suffixes pay exactly the same duty.
The 8- vs 10-digit legal detail and specific measure lists follow the current dataset; the exact statistical suffix for a niche product should be confirmed on the official HTS.
FAQ
- What does each part of an HTS code mean?
- Chapter (2), heading (4), subheading (6 = the international HS code), US rate line (8), and statistical suffix (10). Broad to specific, left to right.
- Why is the HTS code 10 digits but the HS code 6?
- The WCO standardizes 6 digits globally. The US adds a 2-digit tariff-rate line and a 2-digit statistical suffix to reach 10.
- Which digits determine the duty rate?
- Digits 7–8 set the legal rate line, and trade remedies (Section 301/232/122) attach at the 8- or 10-digit level — the 6-digit code alone is not enough.
More guides: all guides · find a code by product · batch classify