How US Import Duty Stacks in October 2026: MFN, Section 301, 232 and What Replaced IEEPA

Short answer: in October 2026 a US import pays the MFN rate from the Harmonized Tariff Schedule, plus whichever Chapter 99 layers apply to its origin and product: the China Section 301 lists, the forced-labour Section 301 tariff that took effect on 24 July 2026, Section 232 duties on steel, aluminium, copper, vehicles and parts, any anti-dumping or countervailing order, and the MPF and HMF fees. The IEEPA "fentanyl" and "reciprocal" tariffs of 2025 no longer apply, and the temporary Section 122 surcharge that briefly replaced them expired in July 2026.

The layers changed three times this year, which is why many duty estimates written in spring are now wrong. This guide walks through each layer in the order a broker builds the entry, then runs three shipments through the stack.

What changed in 2026

Three events reset the US tariff stack this year. Every date below is from the Federal Register or the CBP notice that implemented it.

The layers, in the order they are added

Each layer is calculated on the customs value (the US uses the transaction value, roughly FOB) and reported on its own line of the entry summary, CBP Form 7501. A layer that does not apply simply adds nothing.

Layer 1: the MFN rate

The Most-Favoured-Nation rate is the "General" column of the HTSUS for the 10-digit code. It is the only layer every shipment pays, and it is the one most tools show — which is exactly why a lookup on hts.usitc.gov alone now understates the bill for most origins.

MFN rates run from 0% (smartphones, laptops and most IT goods under the WTO Information Technology Agreement) to over 30% for some apparel, footwear and food. Free trade agreements replace the MFN rate with a preferential one — USMCA, KORUS and the other US FTAs — but only when the goods meet the agreement's rules of origin and the claim is documented.

Layer 2: Section 301 on Chinese goods

The 2018 Section 301 action on China's technology-transfer practices is still in force: Lists 1, 2 and 3 at 25%, List 4A at 7.5%, and the higher strategic-sector rates from the 2024 four-year review — 100% on electric vehicles, 50% on semiconductors and solar cells, 25% on lithium-ion batteries, critical minerals and ship-to-shore cranes. USTR keeps a short list of product exclusions; it amended four of them on 2 September 2026 to follow the July HTS changes.

Section 301 follows country of origin, not where the goods were shipped from. Chinese components assembled in a third country keep Chinese origin unless the processing there is a substantial transformation. Check any code with the Section 301 lookup.

Layer 3: the forced-labour Section 301 tariff (new since 24 July 2026)

In March 2026 USTR opened 60 Section 301 investigations into economies that do not ban imports made with forced labour. The resulting action, published on 28 July 2026 and applied to goods entered from 24 July, is the layer most 2025-era calculators miss.

• 10% on all goods of Argentina, Bangladesh, Cambodia, Canada, Ecuador, El Salvador, Guatemala, Honduras, India, Indonesia, Jordan, Malaysia, Mexico, Pakistan, Sri Lanka, the United Kingdom and Trinidad and Tobago.
• Topped up to 10% net of MFN for the European Union and Taiwan: if the MFN rate is below 10%, the Section 301 rate is the difference; at 10% or more it is zero.
• Topped up to 12.5% net of MFN for Japan, South Korea and Switzerland.
• 12.5% on all goods of every other investigated economy, including China, Vietnam, Thailand, Brazil, Australia and the UAE.

It stacks on top of MFN and the China Section 301 lists. It does not apply to goods already covered by the Section 232 steel, aluminium, copper, vehicle, parts, truck, wood and semiconductor actions, to goods of Canada or Mexico that enter duty-free under USMCA, or to the products on the economy's exemption annex (largely raw materials and goods the US cannot source domestically). TRQs for textiles from Bangladesh, Cambodia, Indonesia and Malaysia are due once USTR finds them feasible.

Layer 4: Section 232

Section 232 duties apply to the product whatever its origin, with rates set by proclamation:

• Steel and aluminium: 50% since June 2025 (25% for the United Kingdom). Derivative products pay on their steel or aluminium content.
• Copper: 50% on semi-finished copper products and derivatives.
• Passenger vehicles and light trucks: 25%, or 15% all-in for the EU, Japan and South Korea under their 2025 arrangements; USMCA vehicles pay only on non-US content.
• Automobile parts: 25% on the covered parts list.
• Medium and heavy trucks: 25% since November 2025, buses 10%.
• Timber, lumber and wood products: separate rates by product.

Where Section 232 applies, the forced-labour Section 301 tariff does not, so the two never stack on the same goods.

Layer 5: anti-dumping and countervailing duties

AD/CVD orders follow a Commerce and ITC investigation and name specific products, origins and exporters. Rates vary from a fraction of a percent to several hundred percent — solar cells from South-East Asia, Chinese aluminium extrusions and wooden bedroom furniture are long-running examples, and new solar cases against Laos and others concluded in September 2026. Check any code against the anti-dumping duty lookup before quoting a price.

What happened to IEEPA and Section 122

In 2025 the administration used the International Emergency Economic Powers Act to impose the fentanyl tariffs on Canada, Mexico and China and the country-by-country "reciprocal" tariffs. On 20 February 2026 the Supreme Court held that IEEPA does not authorise tariffs. Collection stopped and CBP set up a process for court-ordered refunds of IEEPA duties already paid; if you paid them, ask your broker whether your entries are covered.

The same week, a proclamation under Section 122 of the Trade Act of 1974 imposed a 10% surcharge on most imports from 24 February 2026. Section 122 allows at most 150 days without an act of Congress, so the surcharge expired in July 2026. The forced-labour Section 301 action took effect on the day it ended.

Worked example 1: cotton T-shirts from Vietnam

A shipment of men's cotton knit T-shirts (HTS 6109.10.00) from Vietnam with a transaction value of $10,000, by sea:

• MFN: 16.5% × $10,000 = $1,650
• China Section 301: not applicable (Vietnamese origin)
• Forced-labour Section 301: 12.5% × $10,000 = $1,250
• MPF: 0.3464% × $10,000 = $34.64
• HMF: 0.125% × $10,000 = $12.50

Total at the border: $2,947.14, an effective 29.5%. If the same shirts were made in China, List 4A adds another 7.5% ($750), for $3,697.14.

Worked example 2: machine parts from Germany vs Japan

Two shipments of the same pump part with an MFN rate of 2.5% and a value of $20,000:

• From Germany (EU): MFN $500 + forced-labour Section 301 topped up to 10%, so 7.5% × $20,000 = $1,500. Duty total $2,000 (10%).
• From Japan: MFN $500 + top-up to 12.5%, so 10% × $20,000 = $2,000. Duty total $2,500 (12.5%).

Add MPF of $69.28 and, by sea, HMF of $25 to each. For EU goods with an MFN rate of 10% or more, the Section 301 layer is zero.

Worked example 3: steel rebar from South Korea

A $20,000 shipment of carbon-steel rebar (HTS 7214.20.00):

• MFN: free
• Section 232 steel: 50% × $20,000 = $10,000
• Forced-labour Section 301: not applicable — steel covered by Section 232 is excluded
• AD/CVD: rebar from Korea is under an anti-dumping order, with a rate set per exporter
• MPF and HMF: $69.28 + $25

Here the MFN rate is zero and the trade-remedy layers are the whole bill.

How to work out your own stack

1. Classify to 10 digits. Every layer keys off the HTS code. Use the HS code lookup and check borderline products against CBP CROSS rulings.

2. Fix the country of origin. Origin, not shipping point, decides the China Section 301 lists and the forced-labour rate.

3. Check Section 232 first. If the product is steel, aluminium, copper, a vehicle, a covered part or wood, the 232 rate applies and the forced-labour 301 rate does not.

4. Add the Section 301 layers for the origin — the Section 301 lookup covers the China lists.

5. Check AD/CVD for the product and exporter.

6. Add MPF and HMF, then run the numbers in the landed cost calculator.

Rates in this guide were checked against the Federal Register on 3 October 2026. They change by proclamation and notice, so confirm the Chapter 99 lines for your entry date before you price a contract; changes we detect are logged on the tariff tracker.