A US import HTS code is 10 digits: the first six are the international HS code, digits seven and eight set the duty rate, and the last two are a statistical suffix. The supplier's 6-digit HS or Schedule B number is not a US import HTS, and getting the last four digits wrong is how the wrong rate gets paid.
The ten digits, and what each pair does
The Harmonized Tariff Schedule code is ten digits, and each pair has a job. The first six are the international HS code, shared by every country that uses the system. Digits seven and eight are the US rate line: this is where the duty rate lives, and where two products with the same six digits can carry very different rates. Digits nine and ten are the statistical suffix, used for trade data, not for duty.
Green tea is the textbook example: 0902.10.1015. The 0902 is tea, the 10 is green tea in a specific form, and the rest narrows it to the exact product. A handbag in man-made fibers, 4202.92.31, carries 17.6 percent. Change the fiber, change the digits, change the rate. The code is the rate, and the rate is the code.
The supplier's number is not your number
Suppliers send a 6-digit HS code, or a Schedule B number, and importers copy it onto the entry. Both are wrong for a US import. The 6-digit HS code is only the first six digits, and the duty rate lives in digits seven and eight, which the supplier never provided. The Schedule B number is an export classification, used for goods leaving the United States, and it is not a US import HTS at all.
The fix is to classify the product yourself, or to have your broker do it, against the HTS published by the US International Trade Commission at hts.usitc.gov. The supplier's number is a starting point, not an answer. Under 19 CFR 141.90(b), the invoice has to show the HTS subheading and the duty rate, and the importer is the one who owns that line.
Chapter 99: the duties that stack on top
Chapter 99 headings are where the extra duties live: Section 301, Section 232, and the other trade remedy actions. A Chapter 99 heading stacks on top of the general rate, so a product with a 10 percent general rate and a 25 percent Section 301 heading pays 35 percent. The HTS code cleanup has to include Chapter 99, because a product classified perfectly in the general schedule and missed in Chapter 99 is still underpaid, and underpayment is a penalty.
The Chapter 99 lines change constantly, which is why the cleanup is not a one-time job. A new proclamation adds a heading, an exclusion expires, and the stack changes. The importer who classified once and never looked again is the importer who gets the penalty letter.
Binding rulings, and when to ask for one
When the classification is genuinely uncertain, ask CBP for a binding ruling through the CROSS database. CBP interprets and enforces the HTS, and a ruling gives you a written answer you can rely on, usually within about 30 days. The ruling binds CBP, which means the classification cannot be second-guessed at the port, and it binds you too, which is the price of certainty.
Ask for a ruling when the duty difference is large, when the product is new, or when two classifications are both plausible. Do not ask for a ruling on a product you have already been importing under a different classification, because the ruling can go against you, and then you have a written record of the wrong answer. Get the ruling before the first shipment, not after the fiftieth.
Keep reading
Related guides on this site: getting a binding ruling on classification before you ship the order tariff duties stack in USMCA preference claims and verification More from Tariff changes caught before they hit your margins.
Frequently asked questions
What is an HTS code?
A 10-digit Harmonized Tariff Schedule code used for US imports. The first six digits are the international HS code, digits seven and eight set the duty rate, and the last two are a statistical suffix for trade data.
How is an HTS code different from an HS code?
The HS code is six digits and international. The HTS code adds four US-specific digits: the rate line and the statistical suffix. A supplier's 6-digit HS code is not a complete US import HTS.
Where do I find the right HTS code?
The US International Trade Commission publishes the HTS at hts.usitc.gov. CBP interprets and enforces it and issues binding rulings through the CROSS database, usually within about 30 days.
What is a Chapter 99 heading?
A heading in Chapter 99 of the HTS where trade remedy duties live: Section 301, Section 232, and similar actions. Chapter 99 duties stack on top of the general rate, so a product can carry both.