Methodology — sources and verification

Every number this site and its calculators surface traces to a primary, official source. This page documents where the data comes from, how it is verified, and how often.

Sources

The regulatory facts rendered across the hub and the guides come from:

• Federal Register — executive orders and their implementation notices (e.g. EO 14324, which ended the $800 de-minimis exemption on 29 August 2025), Proclamation 11012 (the expired Section 122 surcharge and its end date), and the memorandum of 23 July 2026 and USTR notice that set the Section 301 forced-labor duties.
• U.S. Customs and Border Protection — enforcement announcements and entry-process guidance.
• USITC Harmonized Tariff Schedule — the live HTSUS, the authoritative source for base duty rates and tariff-line classification.
• Supreme Court of the United States — slip opinions, e.g. Learning Resources, Inc. v. Trump (No. 24-1287, 20 February 2026), which struck down the 2025 IEEPA tariffs.
• Congress.gov / CRS — Congressional Research Service legal sidebars summarizing the rulings and the replacement measures.
• USTR — Section 301 list assignments for China-origin goods.

How verification works

• Every regulatory claim on this site carries a verification date. The current dataset was verified on 12 June 2026 against the sources above.
• Each figure is read from the primary source linked beside it. The checking is an AI-assisted process with automated checks, not a promise that a person has re-read every source.
• The dated facts live in one machine-checked dataset inside the site's codebase; automated tests lock each value to its citation, so a value cannot silently drift from the source it claims. A verification date only changes when the figures it dates have been checked again against their sources; a partial re-check gets its own date (see below) instead of moving the dataset date.
• Each guide shows two dates: "Last updated" (when the page content last changed) and "Data verified ... against ..." (when the facts were last re-checked, with the sources linked).

Refresh target

• The target is to re-check the regulatory dataset within 30 days of its verification date. The target is not always met, and when it is missed the pages say so instead of hiding it.
• If more than 30 days pass since the verification date, the site marks its data as stale rather than pretending freshness. That is a mechanical rule, not an intention: the same constant that sets the threshold renders the notice, so this sentence and the badge cannot drift apart.
• Freshness right now: the dataset is 111 days old, past the 30-day target, and every page that prints a figure carries a refresh-due notice. The date only moves after the figures it dates have been checked again against their primary sources, so an ageing date stays visible instead of being papered over.

The regime, with the date each part was checked

• De-minimis ($800 exemption): eliminated 29 August 2025 (China-origin earlier, 2 May 2025) — still suspended. Checked 12 June 2026.
• IEEPA 2025 tariffs: struck down 20 February 2026; CBP ceased collection 24 February 2026. Checked 12 June 2026.
• Section 122 surcharge, expired: 10% ad valorem, all origins, from 24 February 2026 (HTSUS 9903.03.01) until 12:01 a.m. EDT on 24 July 2026, the end of its 150-day window. Checked 1 October 2026.
• Section 301 forced-labor duty: in force since 24 July 2026, no end date. 10% for 17 economies (among them Canada, Mexico, India and the United Kingdom); a top-up to a combined 10% for the European Union and Taiwan and to 12.5% for Japan, South Korea and Switzerland; 12.5% for every other investigated economy, China included. HTSUS 9903.05.20–9903.05.84. Checked 1 October 2026.
• Section 301 (China): in force, 7.5–25% by list. Section 232: in force, product-specific. Checked 12 June 2026.

What the calculators promise — and what they don't

The family's calculators produce planning estimates: they apply the published rates to the values you enter. They do not produce binding classifications or rulings — CBP makes the final determination on every entry, and declared values, classification calls, and courier fees can move the real bill. For commercial imports above $2,500 or restricted-category goods, consult a licensed customs broker.