Customs duty is levied on imported goods that attract a positive rate of duty. The customs duty rate can be an ad valorem rate (e.g. 12% on t-shirts) or a specific duty calculated using elements other than value of the goods, such as weight (e.g. 948.00 EUR / tonne on pet food).
All imported goods must have a customs value. When the customs duty rate is ad valorem one, the rate is applied to the customs value of the imported goods. As such, customs value has a direct impact on the amount of customs duty payable.
But what exactly is a ‘customs value’ and how is this calculated?
Source Blick Rothenberg