6109.10.00 and Section 338 Canada: Rates, Scope, and Stacking

Key Points

• HTS 6109.10.00 covers cotton T-shirts and similar knit garments; the general (MFN) duty rate is 16.5%.
• Goods of Canadian origin entered on or after August 19, 2026 are subject to a Section 338 overlay in addition to the base 16.5% MFN rate; the applicable Section 338 article codes are 9903.03.12 through 9903.03.16.
• A set of Free-rate FTA preferences exists for imports from AU, BH, CL, CO, IL, JO, KR, MA, OM, P, PA, PE, S, and SG, but those preferences do not apply to Canadian-origin goods subject to Section 338.
• Column 2 (non-MFN) goods are subject to a 90% rate, which is separate from and not applicable to Canadian entries covered by Section 338.
• Confirm the exact Section 338 overlay rate and any product-specific exceptions with the current Harmonized Tariff Schedule or your broker before filing.

On this page

1. What HTS 6109.10.00 covers
2. Base MFN rate and FTA preference rates
3. Section 338 Canada overlay: scope and effective date
4. How Section 338 stacks with the base duty
5. Chapter 99 article codes and entry mechanics
6. What importers should do
7. Key references

The links in this article go to the primary documents: the proclamations, Federal Register notices, and official tariff schedule pages themselves. Read the source.

HTS 6109.10.00 classifies knit or crocheted T-shirts, singlets, and similar garments made of cotton. As of August 7, 2026, the general (MFN) rate is 16.5%. For goods of Canadian origin entered on or after August 19, 2026, a Section 338 duty overlay applies on top of that base rate, reported using a Chapter 99 code (9903.03.12 through 9903.03.16) on the same entry line. Importers sourcing cotton knits from Canada need to account for both charges when modeling landed costs.

What HTS 6109.10.00 covers

Heading 6109 of Chapter 61 of the Harmonized Tariff Schedule of the United States (HTSUS) covers T-shirts, singlets, tank tops, and similar garments, knitted or crocheted. The 10-digit subheading 6109.10.00 narrows that to articles of cotton.

The description is deliberately broad. Crew-neck T-shirts, sleeveless undershirts, and cotton tank tops all fall here if they are knit or crocheted and composed of cotton. Construction details, weight, and gender designation do not create separate subheadings at the 10-digit level under this code; confirm your specific article's classification against the current HTSUS text or with a licensed customs broker before relying on this subheading.

For a broader orientation to 2026 tariff code changes, see our 2026 tariff code overview.

Base MFN rate and FTA preference rates

General (Column 1 MFN) rate

The general duty rate for 6109.10.00 is 16.5% ad valorem. This rate applies to imports from any country entitled to most-favored-nation (MFN) treatment unless a special or column 2 rate applies.

Special (FTA/preference) rates

The following countries qualify for a Free rate under their respective trade agreements or preference programs:

• AU (Australia), BH (Bahrain), CL (Chile), CO (Colombia), IL (Israel), JO (Jordan), KR (Korea), MA (Morocco), OM (Oman), P (CAFTA-DR, general), PA (Panama), PE (Peru), S (CAFTA-DR, sugar-sensitive), SG (Singapore)

These Free rates are tied to rules of origin under each individual agreement. Canadian-origin merchandise subject to Section 338 does not benefit from these preference rates; the Section 338 overlay operates independently of FTA treatment for Canada.

Column 2 rate

The Column 2 rate is 90%. Column 2 applies only to goods from countries that do not receive MFN treatment. Canada is an MFN country, so Canadian imports are not subject to Column 2.

Section 338 Canada overlay: scope and effective date

Section 338 is a tariff action targeting goods of Canadian origin. For entries made on or after August 19, 2026, Canadian-origin goods classified under 6109.10.00 are subject to the Section 338 duty overlay in addition to the 16.5% base MFN rate.

The Section 338 article codes covering Canadian goods are 9903.03.12 through 9903.03.16. Each of those codes addresses a specific product category or exception within the Section 338 program. For reference on the specific product carve-outs:

• 9903.03.12 covers Canadian alcohol at a 50% rate. See 9903.03.12 Explained: 50% Section 338 Duty on Canadian Alcohol.
• 9903.03.13 covers Canadian dairy. See 9903.03.13 Explained: Canada Dairy Tariff, 50% Rate, and Scope.
• 9903.03.14 covers motor vehicles. See 9903.03.14 Explained: Canada Motor-Vehicles Tariff.
• 9903.03.15 covers goods with a Section 232 exception. See 9903.03.15 Explained: Section 338 Canada Section 232 Exception.
• 9903.03.16 covers civil-aircraft and related goods. See 9903.03.16 Explained: Section 338 Canada Civil-Aircraft Exemption.

Cotton knit garments under 6109.10.00 do not appear to fall within the alcohol, dairy, motor-vehicle, Section 232, or civil-aircraft carve-outs. Confirm the correct Chapter 99 code for your specific entry with the current HTSUS and your broker. The facts block for this article is current as of August 7, 2026; the August 19, 2026 effective date is drawn directly from that source.

Note: 9903.03.01 through 9903.03.11 are a separate, discontinued Section 122 block and are not applicable to Section 338 entries.

How Section 338 stacks with the base duty

Section 338 duties are cumulative with the base Chapter 1-97 duty. For a Canadian-origin cotton T-shirt entered on or after August 19, 2026, the total duty is the 16.5% MFN rate plus the applicable Section 338 rate from whichever 9903.03.12-9903.03.16 code applies.

This stacking structure is standard for Chapter 99 overlay programs. The base classification line (6109.10.00) carries the 16.5% rate and determines merchandise classification; the Chapter 99 line carries the Section 338 adder and must be reported alongside it on the entry summary. Neither line replaces the other.

Use our duty calculator to model the combined landed-cost impact before committing to sourcing decisions.

For a worked example of how Section 338 stacks on a different product, see 8537.10.91 and Section 338 Canada: Rates, Scope, and Stacking.

Chapter 99 article codes and entry mechanics

Reporting on the entry summary

When filing an entry summary (CBP Form 7501) for Canadian-origin goods subject to Section 338, importers and brokers must report both the Chapter 1-97 classification (6109.10.00) and the applicable Chapter 99 code (the correct code from 9903.03.12 through 9903.03.16) on separate lines. CBP's Automated Broker Interface (ABI) requires both codes to calculate and collect the full duty owed.

Omitting the Chapter 99 line is a filing error that can trigger a post-entry correction, a post-summary correction (PSC), or, in serious cases, a CBP penalty action. For the mechanics of post-summary corrections, see CBP Modifies Post Summary Correction Processing: What Filers Must Know.

Country of origin determination

Section 338 applies only to goods of Canadian origin. Origin is determined under the applicable rules, which for apparel generally require substantial transformation or tariff-shift analysis. If your cotton garments are cut and sewn in Canada from fabric sourced elsewhere, confirm origin qualification with the current rules before assuming Section 338 applies or does not apply.

Recordkeeping

All duty payments, origin documentation, and entry records must be retained for the applicable period. For the rules on retention periods, see Customs Recordkeeping Requirements: The Five-Year Rule Explained.

What importers should do

• Verify classification and the correct Chapter 99 code. Pull the current HTSUS at hts.usitc.gov and confirm that 6109.10.00 is the right 10-digit subheading for your specific garments, and that you are pairing it with the correct 9903.03.12-9903.03.16 code for your product category.
• Model the stacked duty before each shipment. Add the 16.5% base rate plus the applicable Section 338 overlay rate to arrive at the total duty obligation for Canadian-origin cotton knits entered on or after August 19, 2026. Use the duty calculator to run scenarios.
• Audit open entries for correct Chapter 99 reporting. If you have entries dated on or after August 19, 2026 that did not include the Section 338 Chapter 99 code, evaluate whether a post-summary correction is needed before those entries liquidate. Review CBP's PSC processing guidance for current procedures.
• Retain all origin and classification records. Section 338 entries will face heightened scrutiny; maintain documentation supporting Canadian origin and the correct classification for the full retention period required under the five-year rule.

Key references

• Harmonized Tariff Schedule of the United States (HTSUS), hts.usitc.gov - Official source for 6109.10.00 rates, notes, and Chapter 99 Section 338 codes.
• U.S. Customs and Border Protection (CBP), cbp.gov - Entry filing requirements, CSMS messages, and post-summary correction guidance.
• Federal Register, federalregister.gov - Notices and rules implementing Section 338 duties on Canadian goods.
• White House, whitehouse.gov - Presidential proclamations establishing Section 338 authority.
• 8537.10.91 and Section 338 Canada: Rates, Scope, and Stacking - Companion article on Section 338 stacking mechanics for a different product.
• CBP Modifies Post Summary Correction Processing: What Filers Must Know - Current PSC procedures relevant to correcting Section 338 entry errors.
• Customs Recordkeeping Requirements: The Five-Year Rule Explained - Retention obligations for entry and origin documentation.