A duty is a tax a government charges on goods brought into its territory. It is often used interchangeably with import tariff, and both refer to money the importer pays customs before the goods clear the border. How much is owed depends on three things: how the product is classified (its HS code), its declared value, and where it was made or shipped from.
How it works
Every product crossing a border is assigned a Harmonized System (HS) code that identifies what it is. Customs authorities attach a duty rate to each code, and that rate is applied against the declared value of the shipment. Country of origin matters too, because trade agreements and preferential rates can lower or remove the duty for goods from certain countries, while others may face additional charges. The importer of record is responsible for paying, though that cost is often passed down the chain to the buyer.
Why it matters for B2B quoting
Duty is a real line item that changes the total a buyer pays, so leaving it out of a quote leads to disputes at delivery or thin margins you did not plan for. For cross-border B2B orders, it helps to state clearly whether your quoted price includes duty (see Incoterms like DDP versus DAP in the glossary) or whether the buyer settles it on arrival. Being explicit avoids surprises and keeps the accepted quote accurate.
Example
A US merchant quotes a wholesale order of ceramic tableware to a buyer in Canada. The tiles classify under a specific HS code with a 5 percent duty rate. On a declared value of 10,000 USD, the duty is 500 USD. If the quote is sent DDP, the merchant absorbs that 500 and builds it into the price. If it is DAP, the Canadian buyer pays it to customs when the goods arrive.