Regardless of whether the shipment is a gift or not, it is still subject to the customs laws of the destination country. Shipments are cleared through customs based on the country of origin, the value, and the quantity of the goods — not the reason for export. For shipments that are subject to customs duties, a fee or tax must be paid for transporting goods across international borders.

The calculation of duties depends on the value of the taxable goods. For this calculation, goods are identified by a classification code known as the Harmonized System (HS) code.
This system is regulated by the World Customs Organization and is continuously evolving.

Payment of customs duties is typically the responsibility of the recipient. However, the carrier may offer the sender the option to pay these costs at the origin, thus relieving the recipient from having to pay them.

In such cases, following delivery of the shipment, the sender receives an invoice for the duties and taxes that the carrier has paid in advance on their behalf at the destination, along with a small administrative fee.

Taxes are imposed on goods when they cross a political border (although some free trade zones do exist around the world). Taxes are usually associated with protectionism and economic policies that regulate and limit trade between countries.

Normally, taxes are levied on imported goods, although in some cases they may also apply to exported goods.