Importing into the United States rarely costs just the duty rate on your invoice. Between Section 301 tariffs, anti-dumping orders, and the Merchandise Processing and Harbor Maintenance fees, the real number — your landed cost — can be meaningfully higher than the headline duty. This guide explains how each piece is calculated and how to find the figures you need.

Customs value: FOB vs CIF

U.S. duties are charged on the customs (entered) value of your goods, which usually starts from the transaction value on your commercial invoice. Whether freight and insurance are part of that value depends on your Incoterms. On an FOB basis the dutiable value is the goods alone; on a CIF basis it includes international freight and insurance. Even when you value FOB, you should still enter freight and insurance so the landed cost reflects what you actually pay to receive the goods.

Finding your HTS code and rate

Every product has a 10-digit Harmonized Tariff Schedule classification, published by the U.S. International Trade Commission at hts.usitc.gov. The HTS line gives you the general duty rate — most often an ad-valorem percentage, sometimes a specific duty per unit, occasionally both. Classification is the single biggest driver of duty and the most common source of error: a few digits can change the rate by double digits. When in doubt, a licensed customs broker or a CBP binding ruling settles the classification.

Section 301 and anti-dumping tariffs

On top of the normal HTS duty, two trade-remedy programs can apply. Section 301 tariffs, administered by the USTR, add 7.5%–25% on many goods of Chinese origin that appear on the active lists. Anti-dumping and countervailing duties apply to specific products found to be dumped or subsidized, at producer-specific rates that can exceed 100%. These add-ons are layered on the customs value and are independent of your base HTS rate — which is why a 0% base product can still face a 25% effective duty.

MPF, HMF, and the de-minimis rule

CBP charges two user fees. The Merchandise Processing Fee is 0.3464% of customs value on formal entries, bounded by an annually-adjusted minimum and maximum (currently $32.71 and $634.62). The Harbor Maintenance Fee is 0.125% of customs value, but only on cargo arriving by ocean vessel — air shipments pay none. Finally, the de-minimis rule lets shipments valued at $800 or less generally enter duty-free, though the rules and exclusions change over time. This calculator keeps every fee constant in one dated block so you can update it when CBP issues a new fee notice.