How we verify rates

Importers make money decisions on these numbers, so here is exactly where every rate comes from, what the estimates include, and how fast we update when policy changes.

Where each rate comes from

• Base duty (MFN / FTA-preference / Column 2) — the USITC Harmonized Tariff Schedule, refreshed from the official data each revision.
• Section 301 (China) and the forced-labor baseline (10% / 12.5%, effective Jul 24 2026) — the Office of the U.S. Trade Representative and the Federal Register.
• Section 232 (metals and derivatives) — U.S. Department of Commerce proclamations; applied only when you enter the 232 content.
• AD/CVD — Commerce ACCESS; case- and producer-specific, so applied only when you supply the rate.
• CBP fees — Merchandise Processing Fee and Harbor Maintenance Fee per CBP (19 CFR 24.23 / 24.24).
• IEEPA refunds (CAPE) — CBP CSMS guidance and the Court of International Trade docket; see the refund estimator.

What the estimates include — and don’t

A landed-cost estimate is: customs value × base HTS rate, plus Section 301 (China), plus the forced-labor baseline, plus MPF and (on ocean) HMF. Section 232 and AD/CVD are included only when you supply those rates, because they are product-, producer- and case-specific. Freight and insurance are included when you enter them in the calculator (they’re otherwise left out of the duty estimate). Estimates exclude any deferral/periodic-statement timing with CBP. They are planning figures, not binding CBP rulings — the importer of record is responsible for correct classification and duties under CBP’s “reasonable care” standard.

Our update cadence

Tariff policy has changed its legal basis three times in eight months, so speed matters. We aim to reflect an official rate change within 48 hours of publication, and we log every change on the changelog with the date it took effect and the date we applied it. Rates are currently stated as of October 2026. If you spot a rate you believe is wrong, tell us — we’ll verify against the source and correct it.

ShipSeeker is independent and not affiliated with any government agency. Estimates are not legal, tax or customs advice — confirm with a licensed customs broker before filing.