Under 15% metal by weight, the duty is zero.
Over it, up to 50%.
Since 6 April 2026, Section 232 applies to the full customs value of 719 listed HTSUS provisions. The exception is heading 9903.82.03: an article outside chapters 72-76 whose applicable metal is less than 15% of its weight carries no additional duty.
The claim is made per part number. Net weights may already be in your ERP; the metal-only weight and the country of melt and pour or smelt and cast usually are not. Those sit in supplier mill certificates.
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U.S. Note 16(c) to subchapter III, chapter 99, HTSUS (Revision 12, 2026): the metals headings apply “only … where the weight of the applicable metal is at least 15 percent of the weight of the imported article,” and where a provision appears on several lists you “use the aggregate weight of the listed metals.” Reporting mechanics: CBP CSMS #68253075 (3 Apr 2026) and #69252300 (15 Jul 2026).
Section 232 content-gap check
Paste your part list. One line per part: an HTS code, then whatever else is on the line (part number, description). The check runs entirely in your browser. No upload, no account.
Which of these do you have on file today, per part?
| Line | HTS | Scope | Required on the entry line | Gap |
|---|
Scope is read from the 719 provisions listed in U.S. Note 16(c) to subchapter III, chapter 99, HTSUS - Revision 12 (2026), retrieved from the USITC on 28 July 2026. Lists change at each BIS inclusion window (January, May, September). This tool reports what the tariff schedule lists; it does not classify your goods, and it is not customs advice. Your declared classification, and what you file, stay yours and your broker's.
Get the supplier request template
Sent immediately: the request we use for metal weight and origin, including the escalation version for suppliers who have not replied. Your part list comes back with it as a record.
What Millproof does after the check
Collect
Each supplier gets one link and a short form per part number: metal weight, metal value, country of melt and pour or smelt and cast. Reminders, escalation, and a record of who was asked and when.
Extract
Mill certificates and commercial invoices arrive as PDFs and photos. They get read into structured per-part fields with the source document attached to every value.
Prove
A per-SKU ledger with version history, staleness flags, the 15% threshold calculation, an entry-line data pack for your broker, and an audit binder when CBP asks under 19 CFR 163.
Scope changes three times a year at the BIS inclusion windows (January, May, September). Millproof re-runs your catalogue against each new list and reports which parts have entered scope.
The pilot
$299 per month, three months, prepaid. We load your first 250 part numbers, run the supplier campaign for you, and hand back the ledger, the broker data pack and the audit binder.
- Set-up is a spreadsheet or a CSV export. No integration, no IT ticket.
- You keep everything produced, in open formats, whether or not you continue.
- If there is no usable ledger 30 days in, it is refunded in full.
Request a pilot invoice Invoice within one business day, payable by ACH, wire or card. Six slots. Starting order is the order they are paid.
What we are not
Millproof is not a customs broker and does not perform customs business. We do not classify your merchandise, we do not advise on entry or valuation, and we never prepare or transmit anything to CBP. You or your licensed broker do that. What we keep is the evidence behind the numbers you declare - a corporate compliance activity, expressly outside the definition of customs business at 19 CFR 111.1.
Questions
Isn't this my broker's job?
Your broker files with the data you give them. They cannot invent the metal weight of your bracket or the country that poured its steel, and they carry no obligation to chase your suppliers for it. The recordkeeping obligation under 19 CFR 163 sits with you as importer of record, for five years from entry.
What if suppliers never answer?
Some will not. The 15% threshold and the reduced tiers mean a supplier's answer often lowers the duty on your own invoice, so the request carries a financial reason rather than a favour. Where it still fails, what a records demand tests is documented diligence: who was asked, when, what came back, what has gone stale. The ledger is that record whether or not every supplier replied.
What do you need from us to start?
A list of part numbers with HTS codes and supplier names. Existing mill certificates, BOMs or weights speed it up but are not required.
Where does our data live?
In your own workspace, separated from every other customer's, exportable to CSV and PDF at any time and deleted on request within 30 days of cancellation. Nothing is used to train models. Pilot customers get the specifics of where it is hosted in writing before anything is uploaded.
What happens if the tariff goes away?
The obligation to substantiate what you already declared does not go with it. Records stay demandable for five years under 19 U.S.C. 1508, and the same per-part composition and origin ledger answers USMCA content and AD/CVD scope questions.