Import tariffs are usually calculated based on the value of the imported good, and they can be applied to all goods from a specific country or to only certain types of goods. Import tariffs can have both positive and negative effects on a country's economy - they can help domestic producers compete with foreign producers, but they can also lead to higher prices for consumers and hinder international trade.

The conventional view is that import tariffs nearly always lead to a deadweight loss of economic welfare mainly through the effects of higher prices for consumers and the distorting effects of a tariff on market competition, prices and the allocation of scarce resources.