How US Import Tariffs Work

A US import tariff is a tax that the importer of record pays to US Customs and Border Protection (CBP) when goods enter the country. The duty on a shipment is the sum of several layers: the base "General" rate printed in the Harmonized Tariff Schedule (HTS), plus any additional duties under trade laws such as Section 232 or Section 301, plus antidumping or countervailing duties where they apply. Each layer is usually a percentage of the goods' customs value.

This guide explains the system: who sets each layer, how the layers stack, how CBP turns them into a bill, and what changed in 2025–2026. For a quick dollar estimate, start with the category tariff calculator or the HTS-8 tariff lookup.

Who sets US tariff rates?

The Constitution gives Congress the power to "lay and collect" duties, and Congress has delegated pieces of that power through specific statutes. Four agencies run the system day to day:

• US International Trade Commission (USITC) publishes the Harmonized Tariff Schedule, the legal list of product codes and rates.
• Commerce Department runs Section 232 national-security investigations and antidumping/countervailing (AD/CVD) cases.
• US Trade Representative (USTR) runs Section 301 investigations into foreign trade practices.
• CBP classifies, values, and collects duty on each entry and issues binding rulings.

When the President or USTR adds a tariff, the change is published in the Federal Register and written into Chapter 99 of the HTS as a new heading, such as 9903.81.xx for metals. The importer reports that Chapter 99 number on the entry alongside the product's regular 10-digit code.

The layers of duty on a single entry

The General rate applies to almost everything. The other layers depend on what the product is and where it was made. That's why two shipments of "the same thing" from different countries can owe very different duty.

How the 2025–2026 tariff actions fit together

Tariff policy changed more in 2025–2026 than in the previous several decades. Here is the timeline of the actions that still matter, or that matter for refunds.

The 2018–2019 Section 301 tariffs on Chinese goods continue alongside all of this. USTR published a notice continuing those actions on October 7, 2026, and keeps the current lists and exclusions on its Section 301 tariff actions page.

How the layers stack: three worked examples

Stacking rules are written into the Chapter 99 notes for each action. Under the July 2026 Section 301 notice, the new duty applies in addition to the General rate and to other Chapter 99 duties. It does not apply to goods covered by Section 232 metals, autos and parts, wood products, trucks, or patented pharmaceuticals. It also does not apply to goods entered duty-free under USMCA from Canada or Mexico.

Example 1: cotton T-shirts from Vietnam, $10,000 customs value. HTS 6109.10.00 carries a 16.5% General rate. Vietnam is in the 12.5% Section 301 group. Duty = $10,000 × (16.5% + 12.5%) = $10,000 × 29% = $2,900.

Example 2: aluminum extrusions (profiles) from Vietnam, $10,000. HTS 7604.29.10 carries a 5% General rate, and aluminum articles pay 50% under Section 232. Because the product is covered by Section 232, the 12.5% Section 301 duty does not apply. Duty = $10,000 × (5% + 50%) = $5,500.

Example 3: wooden dining tables (not upholstered) from Vietnam, $10,000. HTS 9403.60.80 is duty-free at the General rate. Non-upholstered tables are outside the Section 232 wood action, so only the 12.5% Section 301 duty applies. Duty = $10,000 × 12.5% = $1,250.

Same origin, same invoice value, and the duty ranges from $1,250 to $5,500. Classification and the Chapter 99 rules decide the bill, not the headline rate. How to find your HTS code explains how to land on the right line.

How CBP assesses and collects duty

Customs value

Most duty is computed on transaction value, the price actually paid or payable to the seller, adjusted for items such as assists, royalties, and selling commissions (19 U.S.C. 1401a). The United States values goods without international freight and insurance, so on a CIF invoice you subtract those charges if they are shown separately.

Rate formats

• Ad valorem: a percentage of value, such as 16.5%.
• Specific: a fixed amount per unit, such as cents per kilogram.
• Compound: both together. Some footwear under 6402.99 is "90¢/pr. + 20%." On 1,000 pairs worth $8,000, that comes to $900 + $1,600 = $2,500.

From arrival to final duty

1. Entry. Within 15 calendar days of arrival, the importer or its licensed customs broker files entry documents and posts a customs bond.
2. Release. CBP releases the goods, often before any duty is paid.
3. Entry summary and deposit. The entry summary (CBP Form 7501) and the estimated duty are due within 10 working days of release, or later through a periodic monthly statement.
4. Liquidation. CBP finalizes the duty, typically about 314 days after entry. It can bill more or refund overpayments at this stage.
5. Protest. You have 180 days after liquidation to challenge CBP's decision.

That lifecycle explains why tariff refunds after a court ruling are complicated. Entries that have not liquidated can be corrected relatively easily. Entries that liquidated long ago may require a protest or a lawsuit.

Fees such as the Merchandise Processing Fee, the Harbor Maintenance Fee, and bond premiums are separate from duty. They are covered in the importer landed cost guide.

Current legal status: what the courts have decided

IEEPA tariffs. In Learning Resources, Inc. v. Trump, decided together with V.O.S. Selections, the Supreme Court ruled 6–3 on February 20, 2026 that the International Emergency Economic Powers Act does not authorize tariffs (docket 24-1287). Executive Order 14389 ended the IEEPA tariff actions, and CBP stopped collecting them on February 24, 2026. CBP is refunding IEEPA deposits through its CAPE tool in ACE. Phase 1 opened April 20, 2026 for unliquidated entries and entries within 80 days of liquidation, and Phase 2 opened June 29, 2026 for entries flagged for reconciliation. Finally liquidated entries were not eligible as of CBP's September 30, 2026 update, and the government's appeal of the Court of International Trade's refund order is pending at the Federal Circuit.

Section 122 surcharge. The Court of International Trade held the 10% surcharge unlawful on May 7, 2026 (Slip Op. 26-47), but limited relief to the three importer plaintiffs (Skadden summary). The government appealed, and everyone else paid until the surcharge expired on July 24, 2026. Whether other importers can recover those payments is unresolved.

What is not in dispute. Section 232 and Section 301 tariffs rest on different statutes and were not part of the IEEPA ruling. Plan around them as current law, and watch the Federal Register for changes.

Using this guide with the site's tools

• Need a rate: the category tariff calculator gives a trade-weighted average for 22 product groups, and the HTS-8 lookup gives line-level rates. Both use data as of June 9, 2026 and leave out the General rate, so add it yourself.
• Need to know who bears the cost: read who pays import tariffs.
• Pricing a product line: build the full cost with the importer landed cost calculator.

Nothing on this site is legal or customs advice. Tariff rules changed several times in 2026, so confirm current rates on the HTS and with a licensed customs broker before you commit to a purchase order.