Tandom · Duty calculator
Add country and invoice value for the full duty stack — base + 301 + 232 + AD/CVD + fees.
HTS 3808.91.30.00 is the U.S. Harmonized Tariff Schedule classification for Containing an inorganic substance. It's a 10-digit statistical line in Chapter 38: Miscellaneous chemical products, Section VI: Products of the Chemical or Allied Industries, used by U.S. Customs and Border Protection to determine the duty rate at entry. 6 Chapter 99 tariff modifications currently stack on top of the base rate.
New to HTS codes? Read our guide on how HTS classification works →
Chapter 99 overlays that stack on the base rate
| Code | Authority | Rate |
|---|---|---|
| 9903.80.03 | section_232 | The duty provided in the applicable subheading + 25% |
| 9903.81.84 | section_232 | The duty provided in the applicable subheading + 25% |
| 9903.81.86 | section_232 | The duty provided in the applicable subheading + 25% |
| 9903.81.91 | section_232 | The duty provided in the applicable subheading + a duty of 50% upon the value of the steel content. |
| 9903.81.92 | section_232 | The duty provided in the applicable subheading. |
| 9903.81.98 | section_232 | The duty provided in the applicable subheading + 25% |
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.
Source: CBP CROSS (view all rulings on rulings.cbp.gov →)
HTS 3808.91.30.00 is the U.S. Harmonized Tariff Schedule classification for Containing an inorganic substance. It belongs to Chapter 38 of the HTSUS.
The general (Column 1) duty rate for HTS 3808.91.30.00 is 5%. This is the most-favored-nation (MFN) rate that applies to imports from World Trade Organization member countries.
Yes. Imports of HTS 3808.91.30.00 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 3808.91.30.00 is 25%. This rate applies to imports from countries that do not have normal trade relations with the United States (currently Cuba and North Korea).
Yes — HTS 3808.91.30.00 is covered by section_232 provision 9903.80.03 (The duty provided in the applicable subheading + 25%). 5 additional overlays also touch this code. Open the code page for the full overlay stack with effective dates and country scopes.
No active AD/CVD orders currently flag HTS 3808.91.30.00 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
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.
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A working guide to the inputs, the layers, and the math behind a US entry summary in 2026. Written for brokers, forwarders, and importer compliance teams.
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What changed April 6, 2026, what stayed the same, and how to file a steel, aluminum, or copper line in ACE without leaving duty exposure on the table.
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Drop the Tandom Duty Calculator API into a TMS, broker software, or in-house ERP. Code samples, the response shape, and ACE reporting order, in 2026.
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What the 178 active Section 301 exclusions cover, how to claim 9903.88.69 on an entry, and what changes when the November 10, 2026 deadline passes.
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Where trade compliance APIs fit in a broker's filing pipeline: HTS classification, duty calculation, AD/CVD scope match, and post-summary corrections.
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