Polymers of styrene — HTS 3903
Polymers of styrene, in primary forms
Chapter 39 › Heading 3903
2026 HTS Rev 19 Synced Rules verified Operational
Written to help non-specialists understand this page. Rates, dates, and legal facts come from the official records above and on the linked source.
HTS heading 3903 is a broad product category for polymers of styrene in “primary forms.” These are styrene-based plastics supplied as basic industrial materials—such as granules, pellets, powders, flakes, or similar forms—rather than finished articles made from the plastic. The heading can include different styrene polymers and blends, but the exact scope depends on the tariff text and relevant legal notes.
To reach the correct 8-digit HTSUS code, start with the product’s actual composition and physical form. The lower-level subheadings commonly distinguish the polymer or material type, such as styrene polymers with particular structures or properties, and may further separate products by form or specification. Confirm the complete product description, including whether it is a copolymer, a blend, expanded material, or contains additives, then follow the subheading hierarchy and applicable chapter and section notes.
What to check
- Obtain the supplier’s technical data sheet, safety data sheet, and composition information before classifying the product.
- Confirm that the merchandise is a polymer in primary form, not a finished plastic article or a product classified elsewhere in Chapter 39.
- Identify the principal polymer, copolymer or blend status, physical form, and any relevant expansion, cellular, or additive characteristics.
- Read every subheading level, legal note, and tariff definition leading from heading 3903 to the 8-digit code; do not choose based only on a product name.
- Check prior binding rulings or ask a qualified customs broker or the relevant customs authority when the composition or classification is uncertain.
HTS heading 3903 summary
Polymers of styrene is a 4-digit product category containing 4 published product-code lines in this snapshot. A heading does not carry one universal duty rate; classification must be narrowed to the line matching the product facts.
How to find your code in this category
A heading is a product category. To get the exact duty, narrow from this 4-digit heading to a sub-category (usually by material), then open the 8-digit code that matches your product.
Open any code in the tables below to see its exact duty rate, a duty calculator (enter your shipment value → estimated duty and landed cost), the rate-change history chart, and the country-by-country breakdown (including Section 301/232 add-on duties).
Why you have to click in: a single category can contain products with very different duties. The rate depends on the specific product — its material and construction — and on the country of origin, and those only get pinned down at the 8-digit code level. That is why this page points you to codes instead of showing one rate for the whole category.
Sub-categories
| Code | Description |
|---|---|
| 3903.90 | Other |
Product codes & duty rates
👇 Each row is a specific product code — click a blue code to open its full page with exact duty rates by country, the rate-history chart, and a duty calculator. 👉
| Code | Description | General (MFN) | Special | Column 2 |
|---|---|---|---|---|
| 3903.11.00.00 👉 | Expandable | 6.5% | Free | 15.4¢/kg + 46% |
| 3903.19.00.00 👉 | Other | 6.5% | Free | 15.4¢/kg + 46% |
| 3903.20.00.00 👉 | Styrene-acrylonitrile (SAN) copolymers | 6.5% | Free | 15.4¢/kg + 45.5% |
| 3903.30.00.00 👉 | Acrylonitrile-butadiene-styrene (ABS) copolymers | 6.5% | Free | 15.4¢/kg + 47% |
"Special" shows the free-trade-agreement rate; open a code to see exactly which countries qualify.
Common questions
What products fall under HTS heading 3903?
Polymers of styrene, in primary forms. To classify a specific item you must pick the matching sub-category and 8-digit code above; the right choice usually depends on the material and construction of the product.
How do I choose the right code within this category?
Start from the sub-categories (typically divided by material—for example cotton versus man-made fibers), then open the active 8- or 10-digit code that matches the product. When unsure, a licensed customs broker or a CBP binding ruling can confirm the classification.
Reference information only, not customs, legal, or classification advice. Confirm the current code and rate against the official HTS before you import.