Import duties are charged on all items that enter the country to be sold in the U.S. market. Although import duty laws are very complex and specific duties vary widely, calculating the duty on an item is relatively straightforward using the U.S. Harmonized Tariff Schedule (HTS). Duties are standardized, so you will pay the same price no matter which U.S. port your items enter.
Locate the HTS. Although some companies sell copies of the HTS, you access the entire database for free on the U.S. International Trade Commission website.
Find your item in the HTS. The HTS is broken down into chapters that group similar products together, and within those chapters are categories that describe products more specifically. Find the category that most closely describes the item you are importing.
Identify the duty rate for the item you are importing. Right next to the classification on the HTS, you will see a general import duty for that item. Next to the general rate, you will find any applicable additional tariff rules, such as reduced or additional tariffs based on country of origin. The HTS also lists the units to which the tariff is applied – for instance, 10 cents per shirt or 2.5 percent per kg of cereal. In some cases, tariff is applied per unit, while in other cases, it is calculated as a percentage of the value of the item. Further, some duties are expressed in monetary terms while others are expressed as percentages.
Do the calculation. Take the total value of your items or the total number of items, depending on if the tariff is calculated based on price percentage or unit numbers, and multiply it by the amount of the import duty. If you are importing multiple items of different classifications, you will need to do the calculation individually for each classification.