HTS 2933 — Heterocyclic compounds Tariff Rate (2026)

Under HTS 2933, heterocyclic compounds enter the United States with a 3.7% MFN duty rate as the base MFN rate. Heterocyclic compounds with nitrogen hetero-atoms. Fundamental building blocks for pharmaceuticals and agrochemicals. Beyond the base MFN duty, goods under this heading from most non-EU origins add the Section 301 forced-labor tariff (10% standard, 12.5% for the ~28-economy forced-labor tier such as China, Vietnam, and Thailand), which took over from the expired Section 122 rate on July 24, 2026. EU-origin goods are capped at the 15% all-inclusive EU-US deal ceiling instead. Chinese-origin goods add a Section 301 China tariff of 25% on top. Worked example: a $10,000 shipment under HTS 2933 owes about $370 in MFN duty (3.7%); adding the 10% base forced-labor surcharge brings it to roughly $1,370 from a standard-tier origin, or about $1,620 from a 12.5%-tier origin such as China (before that origin's Section 301 China tariff). Check your exact figure with the tariff calculator. The top countries of origin for HTS 2933 imports include CN, IN, IE, CH, DE. Effective duty varies by source country based on trade agreements (USMCA, KORUS) and tariff programs — see the per-country tariff rates by country for how CN compares.