How to Install and Use the US Tariff Lookup Browser Extension
Invoice × Tariff editorial
Who this is forSellers, sourcing agents and buyers who want duty answers while browsing supplier, marketplace or HTS pages.
Install “US Tariff Lookup” from your browser's add-on store, then look up any product three ways: type a code or description in the toolbar popup, select text on any page and right-click → Look up in US Tariff Lookup, or type tariff plus a keyword in the address bar. Results show the MFN rate, China 301 and Section 232 flags — all computed from data bundled inside the extension, with no network requests.
What the extension does
US Tariff Lookup puts the site's HTS search next to whatever page you are on — a supplier catalog, a marketplace listing, the USITC tariff itself. It answers one question fast: what does this code cost to import? The result shows the MFN duty rate, a red Section 301 badge when China-origin goods are surcharged (with the list and rate), and an amber Section 232 note when the chapter falls in a sector measure's scope.
It is a Manifest V3 extension built for Chrome, Edge and Firefox from one codebase, and it is free.
Install
| Browser | Status | Where |
|---|---|---|
| Microsoft Edge | ✅ Live | Edge Add-ons store page |
| Firefox | 🕑 Under review | Firefox Add-ons (AMO) — this table updates when approved |
| Chrome | 🕑 In preparation | Chrome Web Store — this table updates when published |
After installing, pin the icon from the browser's extensions menu so the popup is one click away.
Three ways to look up
1. Toolbar popup. Click the icon and type a code prefix, English description or Chinese keyword — "8471", "baby strollers" or "保温杯" all work. The bundled data covers the full HTS 8-digit table (5,700+ codes), with curated high-frequency codes carrying Chinese names and Chinese search terms.
2. Right-click on selected text. Select any text on any page — a product title, a code in a spreadsheet, a line in an email — right-click and choose Look up in US Tariff Lookup. If the selection parses as a 6–10 digit code you jump straight to that code; otherwise you land on the calculator with the text as the search.
3. Address bar (omnibox). Type tariff, then space, then your query — tariff 8471 or tariff baby strollers — and get live suggestions as you type. Enter opens the best match.
Reading the result card
- MFN rate pill — the USITC Column 1 general rate, the base layer every shipment pays.
- Red 301 badge — the code sits on a China Section 301 list; the badge shows which list and the surcharge rate. It applies to China-origin goods.
- Amber 232 note — the chapter falls inside a Section 232 sector measure's scope (steel, aluminium, autos and others). The wording is deliberately "or applicable": 232 hits depend on the product and origin, so the extension flags the possibility instead of asserting the duty.
- Deep link — codes with a page on this site link straight to /hts, where the full stack, fees and a live calculator are one click away.
For the complete stacked number — 301 plus global 301 plus 232 plus MPF/HMF fees and landed cost — follow the deep link into the calculator.
Privacy: it works offline, and it stays offline
The rate data is bundled inside the extension — there are no network requests, no analytics, no remote code, and nothing you type leaves your machine. The extension requests exactly one permission (contextMenus, for the right-click entry), which is the minimum needed to function. You can verify all of this: the source is open at us-tariff-lookup-extension.
When the data updates
The bundled snapshot follows the same versioned ruleset as the site and the npm package, refreshed in step with extension updates — check the store listing's version or the Tariff Radar for what changed. If a result looks stale, the deep link always computes live from the current site ruleset.
Same engine, other shapes: this site's web calculator, the npm package for developers, and the offline desktop app.
Frequently asked questions
- Which browsers does the extension support?
- One Manifest V3 codebase covers Chrome, Edge and Firefox. The Edge Add-ons version is live today; the Firefox and Chrome store versions are in review and will be linked from the open source page and this tutorial as soon as they are approved.
- Does the extension send my searches anywhere?
- No. The rate data ships inside the extension, so lookups never touch the network — no requests, no analytics, no telemetry. The only permission requested is contextMenus for the right-click menu, and the source code is public if you want to verify.
- Why does the Section 232 badge say “or applicable”?
- Section 232 measures apply at the chapter level and depend on the specific product and origin, so the extension marks the possibility rather than asserting a duty. The deep-linked code page and calculator resolve the full stack for your exact scenario.
- How many HTS codes does it cover?
- Search runs over the full HTS 8-digit table (5,700+ codes) bundled with the extension; curated high-frequency codes additionally carry richer English and Chinese descriptions and deep links to their pages on this site.
- Is the extension free?
- Yes, free with no account. It is open source under the MIT license alongside the rest of the Invoice × Tariff toolchain.
Edge is live today; the Firefox and Chrome store links are added on this page as each version passes review.