Everything After Digit Six: Why One HS Code Lands on Four Different Tariff Lines

Most of what is written about HS codes stops at the sixth digit, and for good reason. The six-digit subheading is the part the World Customs Organization maintains, the part more than 200 countries and economies share, and the part our classification guide spends most of its time on. Get it right and the goods are identified.

But a six-digit code is not what a customs declaration asks for. The United States, the European Union, Great Britain, and Canada each want ten, and the four extra digits are theirs alone. This post is about that national layer: how each of the four builds it, why the same goods end up on a different number of lines in each, and what goes wrong when a code from one schedule ends up on paperwork bound for another.

The part everyone shares

The Harmonized System is revised on a five to six year cycle. The edition in force today, HS 2022, entered into force on January 1st, 2022 and organizes goods into 1,228 headings and 5,612 subheadings. The next edition, HS 2028, enters into force on January 1st, 2028.

Take a knitted cotton T-shirt. In every one of those 200-plus administrations it is heading 6109, T-shirts, singlets and other vests, knitted or crocheted, and subheading 6109.10, of cotton. That is where international agreement ends.

Four ways to finish the number

United States: 8 legal digits plus a 2-digit statistical suffix

The Harmonized Tariff Schedule of the United States is legal text through the eighth digit. The general statistical notes to the schedule put it precisely: the statistical reporting number “consists of the 10-digit number formed by combining the 8-digit subheading number with the appropriate 2-digit statistical suffix.” The suffixes, their article descriptions, and the units of quantity are annotations for statistical reporting, and the notes are explicit that they are not part of the legal text.

For the cotton T-shirt, the legal line is 6109.10.00, general duty rate 16.5 percent, and under it the US schedule carries 14 statistical lines. They split by whether the garment is all white with no pockets, trim, or embroidery, whether it is a thermal undershirt or underwear, and then by men’s, boys’, women’s, or girls’. Each line also carries a three-digit textile category number in parentheses.

European Union: an 8-digit CN code, then TARIC

The EU’s Combined Nomenclature is the schedule that carries duty rates, and each CN code has an 8-digit code number. It is republished every year: the 2026 version is Commission Implementing Regulation (EU) 2025/1926, published on October 31st, 2025 and applying from January 1st, 2026. If the cycle holds, the 2027 version arrives in late October.

Digits nine and ten are the TARIC layer, which carries the measures attached to an import: preferences, quotas, anti-dumping duties, restrictions. For the cotton T-shirt the CN code is 6109 10 00 and the TARIC layer splits it into just two declarable lines: 6109 10 00 10, T-shirts, and 6109 10 00 90, other. Third-country duty on both is 12 percent. Two lines where the US has fourteen, and the criteria do not overlap: the EU does not ask about colour or the wearer’s sex at this heading.

Great Britain: the same digits, a different tariff behind them

Since January 1st, 2021 the UK Global Tariff has replaced the EU’s Common External Tariff for goods entering Great Britain. The duty rates are the UK’s to set. The code structure, however, has stayed aligned: the UK government’s tariff data standard states that commodity codes contain 10 digits, that digits seven and eight are the CN subheading and nine and ten the TARIC codes, and that “the UK continues to maintain regulatory alignment with the EU, hence the last 4 digits of codes in the UK are the same as those used in the EU.”

So the GB line for the cotton T-shirt is 6109 10 00 10, the same as the EU’s, and on this particular line the two rates happen to agree at 12 percent. That agreement is line by line, and nothing guarantees it. The digits tell you the goods; the rate has to be read from the schedule the goods are actually entering.

Northern Ireland is the exception inside the exception. Goods arriving there that are “at risk” of moving on into the EU are charged the applicable EU rate of duty, and GOV.UK publishes a separate Northern Ireland Online Tariff carrying the EU lines. A consignee address in Belfast can sit on the EU lines, not the GB ones.

Canada: 8-digit tariff item plus a 2-digit statistical suffix

Canada’s structure reads like the American one. The CBSA memorandum on coding customs accounting documents describes the classification number this way: “The first six digits represent the heading and subheading taken from the International Harmonized System, the seventh and eighth digits are the tariff items and the remaining two digits represent the statistical suffix.” A decimal point goes after the fourth, sixth, and eighth digits.

For the cotton T-shirt the tariff item is 6109.10.00, MFN rate 18 percent, and the 2026 Customs Tariff carries six statistical lines under it. Canada splits first by men’s or boys’ versus women’s or girls’, then by the all-white short-sleeve T-shirt, other T-shirts, and other.

What the T-shirt shows

Lay the four schedules side by side and the same six digits produce a different number of lines, split on different criteria, in each:

Three consequences follow, and all three show up on real invoices.

A code from one schedule usually does not exist in another. The US line for an all-white T-shirt is 6109.10.00.04. There is no 6109 10 00 04 in TARIC; the EU offers only 10 and 90. Run the other way, the EU’s 6109 10 00 10 has no counterpart in the US schedule, whose suffixes under this subheading run 04, 07, 11 and so on. A supplier who ships to both markets and keeps one master code per product will be right in one and holding a nonexistent line in the other.

Sometimes the code does exist, and means something else. 6109.10.00.11 is a real line in both the US and Canadian schedules. In the United States it is thermal undershirts. In Canada it is men’s or boys’ all-white short-sleeve T-shirts. Ten identical digits, two different garments. A check that only asks “is this a valid code for the destination” passes it. A check that reads the description against the line does not.

The national digits move on their own calendar. The six-digit layer changes every five to six years. The EU republishes the CN every year. The US schedule is revised repeatedly within a year; the current print is Revision 18 of 2026. A ten-digit code that was correct on last year’s invoice can be a retired suffix on this year’s, with the six digits above it untouched.

Reading a declared code in two halves

Because the layers are maintained by different bodies on different schedules, a declared code is best read as two questions rather than one.

The first is whether the six-digit subheading exists in the current HS edition and fits the goods. That question has the same answer in every administration, which is why a mismatch there is worth resolving before anything else, and why our cross-document check compares at six digits when the papers in a bundle disagree.

The second is whether the digits after six are a currently effective line in the schedule of the country the goods are entering, and whether the description on the line item reads to that line rather than a sibling. This question can only be answered against the destination. A ten-digit code on an invoice with no destination is six digits of information and four of decoration.

The practical habits that fall out of this:

1. Resolve the schedule from the consignee, not the shipper. The destination decides which national layer applies. An EU member state address means TARIC; a Northern Ireland address can mean TARIC too; an English address means the UK tariff; a Canadian address means the Customs Tariff. A Swiss address means none of the four, and a ten-digit code on that invoice is the exporter’s code, not the importer’s.

2. Treat a full code as a claim to verify, not a fact to copy. The cheapest check is whether the suffix exists under its subheading in the destination’s current schedule. The more useful one is whether the description on the line supports that suffix over the others.

3. Keep the six digits and the national digits as separate fields in whatever you store. The six travel across markets; the four do not. Product masters that hold one ten-digit code per SKU are where the cross-schedule errors above come from.

4. Watch the annual dates. The EU’s new CN lands in late October for January 1st. The US schedule revises through the year. A code that was checked in March has not necessarily been checked for September.

Where the document layer fits

CargoLint reads every line item on an invoice or certificate of origin and checks the HS code in exactly those two halves; bills of lading get the narrower check, since a cargo line describes freight rather than a product. The first six digits are checked against the current HS edition and against the line’s own description, everywhere. Beyond the sixth digit, the check runs against the destination’s schedule where that schedule is loaded, and today that is the US Harmonized Tariff Schedule: a ten-digit code on a US-bound invoice is matched against the currently effective statistical lines under its subheading, and where several lines exist, the description decides between them or records the one fact that would.

For every other destination, the line says so. The state reads “6 digits only,” which is a statement of scope rather than a finding: the international part was checked, and the national digits were not, because no schedule is on file to check them against. That is deliberate. A tool that guessed at a TARIC or Canadian line without the schedule loaded would be doing what the copied master code does, and with the same result.

Every finding is advisory. “Tariff line not found” means the suffix is not in the current schedule, not that the goods are misclassified; “Tariff line differs” shows both schedule paths side by side and leaves the pick to the reviewer, who can search the schedule from the line’s own description. What is recorded is which line was chosen and why, which is the part that matters when the entry is questioned.

The fastest way to see how your own invoices split into six and ten: run a recent shipment through the free trial, or send us a bundle for a free accuracy audit.

CargoLint provides document automation software, not customs brokerage or legal advice. Tariff lines and rates quoted above were read from the US, EU, UK, and Canadian schedules as published in September 2026 and change on each administration’s own cycle; confirm the current line with your broker or the destination authority before filing.