Methodology

Nothing on this site is calculated or estimated by us from first principles. Every duty rate, VAT rate, preferential rate and import control is pulled directly from the official government API for that code — GOV.UK Trade Tariff for the UK, the USITC Harmonized Tariff Schedule for the US — and stored as published. See Data sources for exactly which endpoints.

If a code has no rate on file, the page says so and links to the official source, rather than showing a blank or a guessed value.

Some codes genuinely carry more than one applicable rate at once — a UK example is children's clothing, which can have a 0% VAT zero-rate alongside the 20% standard rate, each tied to a real, government-defined condition. When that's the case, the page shows every rate with its condition rather than picking one. Picking a single rate arbitrarily would sometimes just be wrong, and a wrong rate is worse than showing several.

Preferential rates work differently in each jurisdiction. Most US HTS lines have no country-specific program rate at all, so the general (MFN) rate is what's shown prominently. Most UK commodity codes carry a rate for dozens of trade agreements simultaneously — those are surfaced through a trading-partner selector rather than a wall of rows, with the full list available if you want to compare partners directly.

The site is designed to rebuild nightly, pulling every code fresh from the government APIs above. This dataset was last pulled on 29 August 2026 — but don't rely on this page for a specific code's freshness. Every code page carries its own “Rates updated” stamp with the exact date that code's data was pulled, since a rebuild in progress can mean different pages reflect slightly different pulls.

If a rebuild fails, the site is designed to show a staleness warning rather than silently keep serving old rates as if they were current.