Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms:
HTS 3913 (Natural polymers) classifies this product in the US Harmonized Tariff Schedule. Country of origin can add Section 301, Section 232, or IEEPA measures; use the calculator for total duty.
Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms:
How the 10.0% is built.
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1Apply base HTS rateColumn 1 General (MFN) or Special (FTA)
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2Add Section 301 (if origin qualifies)Chapter 99 subheading layered on
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3Add IEEPA / 232 surchargesCountry-scoped emergency measures
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4Add MPF & HMF feesApplied to entered value
Rate by country of origin
Same HTS, very different landed cost. Here's how 3913 looks from the top trading partners — on a $10,000 shipment.
Related HTS codes
Citations for 3913
FAQ for this HTS code.
What is this HTS code?
This is a US Harmonized Tariff Schedule (HTS) code that classifies "Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms:". It determines base duty rates for imports; additional duties may apply by country of origin.
Does origin affect duty?
Yes. General and Special rates apply by trade agreement and origin. Additional duties (Section 301, 232, IEEPA) are origin-specific. Use the tariff calculator or resolve API with an origin to see full duty.
How do I compute total duty?
Use our tariff calculator (with HTS and optional origin) or the API endpoint GET /api/v1/tariffs/resolve with hts and origin. The API returns base tariffs and additional measures separately; sum as needed for your use case.
Tariff programs explained
Temporary and additional duty provisions that stack on top of a base HTS code.
China-origin tariffs (commonly +7.5% to +25%) added on top of the base rate.
National-security tariffs on steel, aluminum, autos, and other covered goods.
Emergency tariffs by country of origin, including reciprocal and fentanyl measures.