Look up a product in the US tariff and you find a duty rate. That rate is real, but for many products it is only the first layer. Depending on where the goods come from and when they enter, other duties are added on top, a trade agreement can lower the base, and fees are due on every entry. What the same code pays can differ widely from one country, or one month, to the next.
The base rate: the General column
Each line of the tariff has three columns of rates. The rate of the General column, also called the normal trade relations or most-favored-nation rate, applies to goods from almost every country: it is the base rate most people quote. The Special column lists lower rates under trade agreements and preference programs. Column 2 holds higher rates for the few countries without normal trade relations with the United States: for their goods, it replaces the General rate.
A rate can be a share of the value of the goods, an amount per unit (per kilogram, per dozen, per liter), or both; many lines are simply "Free".
Additional duties: Chapter 99
Chapter 99 of the tariff holds the duties added to the base rate for some products, some countries or some periods. Each comes from its own legal act, with its own products, countries and dates. The main ones TariffTrust calculates:
- Section 301
- Extra duties the US Trade Representative sets on goods from some countries, in response to their trade practices; best known for the duties on many goods from China.
- Section 232
- Extra duties on goods the Department of Commerce found to threaten US national security, such as steel, aluminum, copper or vehicles. They often reach every origin, and some are charged on the value of the metal a product contains.
- Section 201
- Temporary safeguard duties on imports that harm a US industry.
- Section 338
- Extra duties on goods from a country that discriminates against US commerce.
These duties do not always simply add up. Their texts say how they combine: one can replace another, exempt a product from it or cap the total, and many apply only to products that meet a condition. That is why an estimate may ask questions about the goods. The pages on Section 301, Section 232, Section 201 and other programs list the measures in service.
The country and the date decide
The General rate is the same for every country with normal trade relations; additional duties are not. Most name the countries they apply to, or those they spare. And they change often: a new action can take effect days after it is announced, sometimes at a stated hour, and end or change months later. A duty is therefore always for one country of origin and one date: the date of entry of the goods.
Trade agreements can lower the base
In the Special column, a lower rate, often "Free", is followed by the symbols of the agreements that give it, in parentheses: S for the USMCA, KR for Korea, AU for Australia, and so on. The lower rate applies only when the goods meet the agreement's rules of origin and the importer claims it on the entry, with the proof the agreement requires.
TariffTrust offers only the agreements that the line names for your country of origin, with the rate each would give. Choosing one is your declaration that the goods qualify: TariffTrust does not verify it. An agreement lowers the base rate; it changes an additional duty only where that duty's own text says so.
Entry fees come on top
- Merchandise processing fee (MPF). US Customs' fee for processing the entry: a share of the value, within a minimum and a maximum, adjusted each fiscal year. Goods that qualify under some trade agreements are exempt.
- Harbor maintenance fee (HMF). A share of the value of goods that arrive by sea, for the upkeep of US ports.
Both are counted once for the whole entry: adding up separate estimates of the products of one entry gives a wrong MPF.
What stays outside
- Antidumping and countervailing duties. The Department of Commerce sets them case by case, on goods of particular producers and countries. They are not in the tariff schedule, and TariffTrust does not calculate them.
- Taxes and fees other than the MPF and the HMF.
- The costs around the goods. Freight, insurance and your customs broker's fees are not duties. Duties are charged on the customs value: in most cases the price paid to the seller, without international freight and insurance.
The stack, in order
For one product, one country of origin and one date, an estimate stacks:
- the base duty: the General rate, the Special rate of an agreement you claim, or the Column 2 rate;
- each additional duty of Chapter 99 that applies to that origin on that date, combined as its text says;
- the entry fees: the MPF, and the HMF for goods that arrive by sea.
Their total is the estimate: what the goods owe when they enter, on top of their price.
Updated October 24, 2026. General information as of that date, not legal or customs advice: the official texts prevail, and a licensed customs broker can confirm what applies to your goods.