Data: UK Trade Tariff API (gov.uk), Open Government Licence v3. How this is verified →
Declarable codes under 391000
UK import duty is charged on a declarable 10-digit code.
- 3910000010Liquid poly(methylhydrosiloxane) with terminal trimethylsilyl groups (cas rn 63148-57-2) with a purity by weight of 99,9 % or more
- 3910000015Dimethyl, methyl(propyl(polypropylene oxide)) siloxane (cas rn 68957-00-6), trimethylsiloxy-terminated
- 3910000020Block copolymer of poly(methyl-3,3,3-trifluoropropylsiloxane) and poly[methyl(vinyl)siloxane]
- 3910000025Preparations containing by weight: - 10 % or more, 2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy] disiloxanyl] propoxy] prop…
- 3910000035Preparations containing by weight: - 30 % or more, α -butyldimethylsilyl- ω -(3-methacryloxy-2-hydroxypropyloxy)propyldimethylsilyl-polyd…
- 3910000040Silicones of a kind used in the manufacture of long term surgical implants
- 3910000045Dimethyl siloxane, hydroxy-terminated polymer with a viscosity of 38-100 mpa·s (cas rn 70131-67-8)
- 3910000050Silicone based pressure sensitive adhesive in solvent containing copoly(dimethylsiloxane/diphenylsiloxane) gum
- 3910000055Preparation containing by weight: - 55 % or more but not more than 65 % of vinyl terminated polydimethylsiloxane (cas rn 68083-19-2), - 3…
- 3910000070Passivating silicon coating in primary form, to protect edges and prevent short circuits in semiconductor devices
- 3910000085Two-component silicone, with a viscosity of the mixture of 3 000 cps or more, but not more than 6 000 cps (according to standard gb/t 279…
- 3910000090Other
Source: GOV.UK Trade Tariff API (Open Government Licence v3)
How UK import duty is calculated
UK customs duty is charged on the CIF value (Cost + Insurance + Freight) of imported goods. The duty rate depends on the commodity classification (HS/tariff code) and the country of origin. After duty is applied, VAT at 20% is charged on the combined CIF value plus duty amount.
The UK has preferential trade agreements with many countries that reduce or eliminate duty. These require proof of origin documentation. This calculator shows the standard third-country duty rate by default and flags when a preference may be available.
Understanding CIF value
HMRC calculates duty on the CIF value of your goods — the cost of the goods plus insurance and freight to the UK port of entry. If you're buying on an EXW or FOB basis, you need to add the freight and insurance costs to arrive at the CIF value. If the price already includes delivery (CIF, CIP, DAP, DDP terms), the customs value is typically the invoice value. Getting this wrong is one of the most common causes of unexpected duty bills.
How duty rates are determined
The UK Global Tariff replaced the EU Common External Tariff after Brexit. Duty rates depend on two factors: the commodity code (a 10-digit classification that identifies exactly what you're importing) and the country of origin (where the goods were manufactured, not where they were shipped from). Electronics like laptops (8471) are 0% duty under the Information Technology Agreement. Clothing (6204) carries 12% duty from most countries. Food products can have complex duty structures including specific duties (per kg) alongside ad valorem rates.
Preferential trade agreements
The UK has free trade agreements with the EU (TCA), Japan (CEPA), Australia, New Zealand, Canada, South Korea, Singapore, Vietnam, and many others through the DCTS (Developing Countries Trading Scheme). These can reduce or eliminate duty entirely, but you need valid proof of origin documentation — typically a supplier's declaration or an origin statement on the invoice. Without proof of origin, the standard third-country duty rate applies even if an FTA exists.
VAT on imports
Import VAT is charged at the UK standard rate of 20% on most goods (5% reduced rate on some items like children's car seats, 0% on certain foods, books, and children's clothing). The VAT is calculated on the CIF value plus the duty amount — so you pay VAT on the duty itself. VAT-registered businesses can reclaim import VAT on their VAT return, making the effective cost just the duty. The Postponed VAT Accounting (PVA) scheme allows UK VAT-registered importers to account for import VAT on their return without paying it at the border.
When to use this tool vs a customs broker
This calculator gives you a reliable estimate for standard imports. Use it for budgeting, quoting landed costs to customers, or checking whether an import is commercially viable. For actual customs declarations, you should use a licensed customs broker or freight forwarder — they handle classification, preferential origin claims, trade remedies, and compliance requirements that go beyond a simple duty/VAT calculation. For complex goods (chemicals, dual-use items, food products), professional classification advice is essential. For official rates, check the GOV.UK Trade Tariff directly.
Estimate only. Not for customs declaration purposes. Duty rates from GOV.UK Trade Tariff API. Verify with HMRC or a licensed customs broker before import. Does not include anti-dumping duties, quotas, or seasonal rates.