In economics, a duty is a kind of tax, often associated with customs, a payment due to the revenue of a state, levied by force of law. It is a tax on certain items purchased abroad. Properly, a duty differs from a tax in being levied on specific commodities, financial transactions, estates, etc., and not on individuals; thus it is right to talk of import duties, excise duties, death or succession duties, etc., but not of income tax as being levied on a person in proportion to his income.

Customs duty

Customs duty is a kind of indirect tax which is realized on goods of international trade. In economic sense, it is also a kind of consumption tax. Duties levied by the government in relation to imported items is referred to as import duty. In the same vein, duties realized on export consignments is called export duty. Tariff which is actually a list of commodities along with the leviable rate (amount) of Customs duty is popularly understood as Customs duty.

Calculation of Customs duty

Calculation of Customs duty depends on the determination of what is called assessable value in case of items for which the duty is levied ad valorem. This is often the transaction value unless the Customs officers determines assessable value in accordance with Brussels definition.

However, for certain items like petroleum and alcohol, Customs duty is realized at a specific rate applied to the volume of the import or export consignments.