Tandom · Duty calculator
Add country and invoice value for the full duty stack — base + 301 + 232 + AD/CVD + fees.
HTS 3921.11.00.00 is the U.S. Harmonized Tariff Schedule classification for Of polymers of styrene. It's a 10-digit statistical line in Chapter 39: Plastics and articles thereof, Section VII: Plastics and Articles Thereof; Rubber and Articles Thereof, used by U.S. Customs and Border Protection to determine the duty rate at entry. No Chapter 99 tariff modifications (Section 301, Section 232, IEEPA) or AD/CVD orders currently flag this code in Tandom's catalog.
New to HTS codes? Read our guide on how HTS classification works →
Past CBP decisions classifying real products under this HTS code. Useful precedent when classifying a similar product — each ruling shows how CBP interpreted the code for a specific case.
The tariff classification and country of origin of cellular polystyrene sheets and shiplap boards
The tariff classification of cellular polystyrene sheets from Canada
The tariff classification and status under the North American Free Trade Agreement (NAFTA), of beauty salon sheets from Canada; Article 509
The tariff classification of foamed polystyrene board from Japan.
The tariff classification of polystyrene foam boards from China.
Source: CBP CROSS (view all rulings on rulings.cbp.gov →)
HTS 3921.11.00.00 is the U.S. Harmonized Tariff Schedule classification for Of polymers of styrene. It belongs to Chapter 39 of the HTSUS.
The general (Column 1) duty rate for HTS 3921.11.00.00 is 5.3%. This is the most-favored-nation (MFN) rate that applies to imports from World Trade Organization member countries.
Yes. Imports of HTS 3921.11.00.00 from countries party to a trade program (such as USMCA, KORUS, GSP, or the African Growth and Opportunity Act) may qualify for the special rate: Free (A,AU,BH,CL,CO,D,E,IL,JO,KR,MA,OM,P,PA,PE,S,SG). Eligibility depends on rules of origin and certification.
The Column 2 rate for HTS 3921.11.00.00 is 80%. This rate applies to imports from countries that do not have normal trade relations with the United States (currently Cuba and North Korea).
No active Chapter 99 tariff overlays (Section 301, Section 232, IEEPA reciprocal, etc.) currently flag HTS 3921.11.00.00 in Tandom's catalog. Use the calculator's date + origin inputs to confirm against any retroactive overlay you may be filing.
No active AD/CVD orders currently flag HTS 3921.11.00.00 in Tandom's catalog. Tandom monitors Federal Register notices daily; a flag will appear here within 24h of any new order's publication.
Free Trade Agreement and special-program eligibility
Tandom guides relevant to this code
Where trade compliance APIs fit in a broker's filing pipeline: HTS classification, duty calculation, AD/CVD scope match, and post-summary corrections.
Open resource
Run thousands of product descriptions through HTS classification, score the confidence, and triage borderline rows. Public search endpoint plus the closed-beta three-layer Classifier.
Open resource
How to read, order, and report Chapter 99 HTS codes alongside the base classification on a US entry summary in 2026. The full stacking ladder for brokers and compliance teams.
Open resource
Why raw LLM prompts fabricate stat suffixes, why MCP-augmented prompts do not, and the prompt template a broker can hand to Claude or ChatGPT today.
Open resource
What changed for low-value DTC and ecommerce shipments after Section 321 de minimis was suspended in 2025. Filing, fees, and duty math through 2027.
Open resource
Turn a PDF commercial invoice into ACE-ready entry data. Which fields to extract, how to chain extraction into HTS classification and duty calculation.
Open resource