How the Brexit Calculator works
Since 1 January 2021, goods moving between the UK and the EU are no longer part of a single customs union. This calculator estimates the two direct charges that Brexit added to that trade lane — customs duty and import VAT — using the same CIF-based formula that customs authorities use to assess charges at the border.
The formula
Start with the CIF value: the goods value plus shipping and insurance. Customs duty is charged as a percentage of the CIF value, unless the goods qualify for a preferential rate. Import VAT is then charged on the CIF value plus that duty — not on the goods value alone:
CIF = Goods value + Shipping & insurance
Duty = CIF × Duty rate (0% if preferential origin applies)
VAT = (CIF + Duty) × VAT rate
Total landed cost = CIF + Duty + VAT
Worked example
Take a £1,000 shipment with £50 of shipping and insurance, a 4% duty rate, no preferential origin, and the standard 20% VAT rate. CIF = £1,050. Duty = £1,050 × 4% = £42. VAT = (£1,050 + £42) × 20% = £218.40. Total landed cost = £1,050 + £42 + £218.40 = £1,310.40 — of which £260.40 is duty and VAT that would not have applied to the same shipment moving within the EU single market before Brexit.
Rules of origin and the UK Global Tariff
The UK-EU Trade and Cooperation Agreement (TCA) allows tariff-free trade for goods that meet its rules of origin — broadly, goods that were substantially produced in the UK or EU rather than merely routed through one. Goods that meet the rules and are accompanied by a valid origin declaration qualify for the 0% preferential rate. Goods that do not meet the rules are charged the UK Global Tariff (UKGT) rate that applies to their commodity code, which varies by product and can be zero, a flat percentage, or a specific amount per unit.
Why import VAT is not always a net cost
Import VAT is charged on nearly all commercial imports regardless of origin — it is not a Brexit-only charge, but Brexit removed the exemption that let EU-origin goods move without it. A VAT-registered business can normally reclaim import VAT as input tax on its next VAT return, so the charge is largely a cash-flow timing effect rather than a permanent cost. For a private consumer or a non-VAT-registered business, import VAT is a real added cost with no equivalent reclaim.
What this calculator does not cover
This tool models only the standard duty and VAT calculation. It does not include customs declaration or brokerage fees, courier handling charges, anti-dumping or safeguard duties on specific products, or the time cost of border delays — all of which vary by carrier, product, and shipment and sit outside the standard formula.