How US Import Duty Stacks in 2026: MFN + Section 301 + 232 + IEEPA + ADD/CVD

Short answer: US import duty in 2026 is no longer a single rate looked up in the HTS. It's a stack of up to five separate tariff regimes that layer on top of each other: (1) the standard MFN rate, (2) Section 301 surcharges on Chinese-origin goods, (3) Section 232 national-security tariffs on steel/aluminum/autos, (4) IEEPA tariffs imposed by executive order since February 2025, and (5) anti-dumping and countervailing duties on specific products from specific origins. For a Chinese-origin steel or apparel SKU, the combined burden in 2026 frequently exceeds 60% of customs value before MPF and HMF fees.

This post walks through every layer, in order, with worked examples and the cliff-notes for what each regime actually does.

The five layers, top to bottom

Each layer is collected by US Customs and Border Protection at the border. They are calculated separately, in a specific order, and reported on different parts of the entry summary (CBP Form 7501).

Layer 1: MFN duty (the base)

The Most-Favoured-Nation duty is the standard rate listed in the Harmonized Tariff Schedule of the United States (HTSUS) for a given 10-digit HTS code. Every product has an MFN rate. It applies to imports from any country with which the US has WTO MFN treatment (most countries) and is the baseline rate before any other regime kicks in.

MFN rates range from 0% (e.g., smartphones at 8517.13.00 — bound at 0% under the WTO ITA) to over 30% on certain agricultural products and apparel. The MFN rate is what you'd find on hts.usitc.gov.

Layer 2: Section 301 (China-only)

Section 301 of the Trade Act of 1974 authorizes the USTR to impose additional duties to address unfair foreign trade practices. The 2018 USTR investigation into China's intellectual-property practices led to four lists of Chinese-origin goods carrying additional tariffs: List 1 (25%), List 2 (25%), List 3 (25%), and List 4A (7.5%). The 2024 USTR review added higher rates on EVs (100%), batteries (25%), solar cells (50%), and semiconductors (50%).

Section 301 is layered on top of MFN and applies by country of origin, not country of shipment. A Chinese-origin product trans-shipped via Vietnam still carries Section 301 — the US Customs origin determination is based on where the substantial transformation occurred. Use the [Section 301 lookup](/tools/section-301-lookup) to check the current rate for a specific HS code.

Layer 3: Section 232 (steel, aluminum, autos)

Section 232 of the Trade Expansion Act of 1962 authorizes additional tariffs when the President, advised by Commerce, finds that imports of a product threaten US national security. Active Section 232 measures in 2026:

- Steel — 25% on imports of steel mill products from most origins (since 2018, with various country quota arrangements that have shifted over time). - Aluminum — 25% on aluminum imports (raised from 10% in 2025). - Passenger vehicles and light trucks — 25% on imports of finished passenger vehicles and light trucks (added under 2025 proclamations). - Covered auto parts — 25% on a list of "covered auto parts" published by Commerce; the list has been expanded twice in 2025–2026. - Selected derivatives — steel pipe fittings and aluminum extrusions used in construction.

Section 232 applies to imports from any origin. A few country quota arrangements (EU, UK, Japan, Korea) suspend Section 232 within an annual cap, with above-quota imports reverting to 25%. See the [Section 232 lookup](/tools/section-232-lookup) for current scope by HS code.

Layer 4: IEEPA tariffs (the 2025 wildcard)

The International Emergency Economic Powers Act of 1977 (IEEPA) is a broad emergency-powers statute. Beginning in February 2025, IEEPA was used as a general-purpose tariff authority — distinct from the trade-specific procedures of Section 301 and Section 232. The procedural threshold is much lower: a presidential declaration of national emergency, no investigation required.

Categories of IEEPA tariff in force at various points during 2025–2026:

- Fentanyl tariffs on Canada, Mexico, and China linked to fentanyl trafficking (initially 25%, with carve-outs negotiated bilaterally). - Reciprocal tariffs — country-specific rates against trading partners based on bilateral trade deficits, ranging from 10% to 50% depending on the country. - Product-specific IEEPA tariffs — e.g., copper, lumber.

IEEPA is currently the subject of pending litigation in the US courts. As of mid-2026, the litigation is ongoing and importers should plan for IEEPA rates to remain in force unless and until a court vacates them. See the [IEEPA tariffs glossary](/glossary/ieepa-tariffs) for the legal background.

Layer 5: Anti-dumping and countervailing duties (AD/CVD)

Anti-dumping duties (ADD) address goods sold below fair market value. Countervailing duties (CVD) address goods that received government subsidies. Both are imposed after a formal investigation by the Commerce Department and ITC, and result in a published order listing specific products, specific origins, and specific rates per exporter.

AD/CVD rates vary wildly — single digits for some orders, several hundred percent for others. Solar cells from China carry combined ADD/CVD over 200% in some periods. Steel rebar from various origins carries ADD between 10% and 80%. Use the [anti-dumping duty lookup](/tools/anti-dumping-duty) to check current orders by HS code and origin.

AD/CVD is product-specific and country-specific. It does not apply broadly — only when an order is in force for your exact product × origin combination.

Worked example #1: cotton T-shirt from China

Take a $10,000 shipment of cotton T-shirts (HTS 6109.10.0012) from China to the US in 2026. CIF arrived value $10,500. Customs value (US uses FOB transaction value) = $10,000.

- MFN duty: 16.5% × $10,000 = $1,650 - Section 301 (List 4A): 7.5% × $10,000 = $750 - Section 232: not applicable (apparel) - IEEPA (China reciprocal tariff, 2026 rate variable): assume 10% × $10,000 = $1,000 - AD/CVD: not currently in force on cotton T-shirts from China - MPF: 0.3464% × $10,000 = $34.64 - HMF (ocean): 0.125% × $10,000 = $12.50

Total owed at the border: $3,447.14 — a 34.5% effective rate on the $10,000 shipment, before US sales tax (state-level, varies). Compare to a Vietnam-origin equivalent: just MFN ($1,650) + MPF + HMF = ~$1,697. The Section 301 + IEEPA stack adds roughly $1,750 per $10,000 of Chinese cotton apparel.

Worked example #2: smartphone from China

A $50,000 shipment of smartphones (HTS 8517.13.00) from China:

- MFN duty: 0% (WTO ITA bound rate) = $0 - Section 301: smartphones currently EXCLUDED from Section 301 lists, status verified May 2026 = $0 - Section 232: not applicable - IEEPA reciprocal tariff: applies if active for China — assume 10% × $50,000 = $5,000 - AD/CVD: not in force on smartphones from China - MPF: 0.3464% × $50,000 = $173.20 (under cap) - HMF: 0.125% × $50,000 = $62.50

Total: $5,235.70 — about 10.5% effective. The smartphone Section 301 exclusion (preserved since 2019) is the major reason Apple, Samsung, and others have continued importing assembled phones from China. The IEEPA layer is the new variable in 2025–2026.

Worked example #3: Korean steel rebar

A $20,000 shipment of carbon steel rebar (HTS 7214.20.0090) from South Korea:

- MFN duty: 0% (steel rebar is duty-free under MFN) = $0 - Section 301: not applicable (Korea-origin) - Section 232: 25% × $20,000 = $5,000 — *unless* within Korea's negotiated steel quota for 2026 - IEEPA: depends on current Korea-specific rate; verify CBP CSMS - AD/CVD: rebar from Korea carries an AD order (rate varies by exporter — check ITA database) - MPF: 0.3464% × $20,000 = $69.28 - HMF: 0.125% × $20,000 = $25

This is the case where the MFN base is 0% but the additional layers dominate. Section 232 alone is 25% of customs value, and ADD on top can push the effective rate over 50% even before IEEPA.

How to compute your stack

For any specific shipment, in 2026, the workflow is:

1. Classify the product to the right 10-digit HTS code. Wrong code = wrong duty across every layer. Use the [HS code lookup](/tools/hs-code-lookup) and verify borderline cases against CBP CROSS rulings.

2. Determine country of origin. Substantial transformation, not country of shipment. Section 301 and IEEPA both depend on origin.

3. Look up MFN duty on USITC HTS or via the [import duty calculator](/tools/import-duty-calculator).

4. Check Section 301 — only applies to Chinese-origin. [Section 301 lookup](/tools/section-301-lookup).

5. Check Section 232 — only applies to steel, aluminum, autos, covered derivatives. [Section 232 lookup](/tools/section-232-lookup).

6. Check IEEPA — verify current CBP CSMS for the latest country-specific rate.

7. Check AD/CVD — only if there's an active order on your product × origin. [Anti-dumping lookup](/tools/anti-dumping-duty).

8. Add MPF and HMF — formal entries always include MPF; ocean shipments include HMF.

The Dutiable [import duty calculator](/tools/import-duty-calculator) does steps 3–8 in one call when you enter HS code, origin, and shipment value.

Bottom line

In 2024, the US import duty calculation for most products was: MFN rate from HTS, plus Section 301 if Chinese-origin. In 2026, that's incomplete. Section 232 has expanded to autos, IEEPA has become a general-purpose tariff lever, and AD/CVD orders continue to multiply on commodity inputs.

The practical implication for importers: a single-rate lookup on hts.usitc.gov is no longer sufficient pricing intelligence. You need a tool — broker, software, or in-house — that resolves all five layers per shipment. Get the stack right and price accordingly; get it wrong and the difference between projected and actual landed cost can erase the margin on the SKU.