The Harmonized Tariff Schedule (HTS) is the 10-digit classification system US Customs and Border Protection uses to assign duty rates and monitor imports. Every TariffWatch alert, digest, and rebuttal starts with an HTS code. This guide walks the lookup, the watchlist add, and the adjacency monitoring that catches sweep risk before it hits.
Step 1: Find the right HTS code
The canonical source is the US International Trade Commission's HTS lookup on hts.usitc.gov, which lets you search by keyword, chapter, or code prefix. For a shipment you're already importing, the fastest path is your commercial invoice or CBP entry summary (Form 7501), which lists the 10-digit HTS by line. If you don't have a filed entry yet, walk the schedule: pick the chapter (98 chapters organized by material or use), then the heading (4-digit), then the subheading (6-digit is the international HS code shared with WTO trading partners), then the 8-digit tariff-line number and finally the 10-digit statistical suffix. CBP publishes classification guidance at CBP's classification rulings on cbp.gov and issues binding rulings on request if you need certainty for a novel product.
Step 2: Confirm the code with a customs broker if the classification is contested
Some products can plausibly fall into more than one HTS code; the duty rate can differ substantially by choice. A licensed customs broker can review your product and confirm the correct code. If you want a legally binding answer, file a Cross Ruling request through CBP's eRulings Template; ruling letters are public and enforceable at rulings.cbp.gov.
Step 3: Add to watchlist
In TariffWatch, open the Watchlist tab and paste the 10-digit HTS. Add a short label (usually your product name), your typical shipment quantity and value, and your product's country of origin. The country of origin is required because Section 232 and Section 301 rates vary by origin (China-origin steel is treated differently than Japan-origin steel; Meta's own USTR Section 301 tariff modification history on ustr.gov documents the country-specific exclusion lists).
Step 4: Choose alert thresholds
You'll set two thresholds per code: rate-change threshold (default: alert on any rate change) and Federal Register notice threshold (default: alert on any BIS, USTR, or CPSC notice that mentions the code or an adjacent code). Adjacency is TariffWatch's edge: the scanner watches the codes that share your 8-digit tariff-line number and the codes CBP has historically flagged as substitutes on rebuttal letters, so a proclamation that adds your neighbor to a Section 232 derivative-article list triggers your alert too.
Step 5: Route the alerts
Alerts route to your account email by default, and can be duplicated to a Slack channel, a Microsoft Teams channel, or a webhook (see webhook Slack setup and webhook Teams setup). For teams that live in email, the understanding your weekly digest article walks the every-Monday summary that consolidates alerts without spam.
Step 6: Bulk-add via CSV (optional)
If you have more than ~15 HTS codes, the fastest add path is CSV import. The schema and walkthrough are in CSV import and export. Firms tracking 100+ HTS lines usually script the CSV from their ERP.
How TariffWatch sources rate data
Every rate change is sourced from a Federal Register proclamation. The full FR archive lives at federalregister.gov, and TariffWatch mirrors the CBP HTS updates plus the USTR Section 301 notices plus the BIS Section 232 proclamations. When a notice publishes, our watcher tags every HTS code mentioned and every code adjacent to a mentioned code, then fans out alerts within 5 minutes of Federal Register publication time.
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FAQ
Can I add an HS code (6-digit) instead of an HTS code (10-digit)? Yes for coarse tracking, but the alerts will be noisier because HS-code monitoring catches every 10-digit US suffix under the 6-digit prefix. Prefer 10-digit codes when you have them.
What if my HTS code changes on a Harmonized System revision? WCO revises the HS every 5 years, and CBP retires and renumbers US HTS codes correspondingly. TariffWatch automatically remaps your watchlist across revisions and posts a "renumbered from" note on the alert.
Do watchlist entries auto-detect the underlying MFN rate? Yes, but MFN rate alone is rarely the interesting number. The Section 232 or Section 301 rate on top of MFN is where alerts come from.
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