How do you calculate customs duties and taxes on an import into the UK?

'Duty' is based on the Customs Value of the commodity.

 It is the sum of:  

• The value of the goods declared on the Air Waybill
• The transportation cost
• Insurance and other costs

Local customs convert the value of the goods into local currency at the time of entry.  Some commodities are subject to other charges such as Excise Duty and CAP levies.