Calculate Import Duty: South Korea to USA

The Korea-US Free Trade Agreement (KORUS) entered into force on 15 March 2012 and completed its staged tariff elimination on most industrial goods by 2016. KORUS makes South Korea one of the most tariff-favored sources for the US market, especially for vehicles, electronics, machinery, and chemicals.

The complication in 2026 is Section 122. While USMCA is fully exempt, KORUS goods are only partially exempt under a March 2026 amendment carving out semiconductors, EV batteries, and certain pharmaceutical APIs. Other KORUS-qualifying categories pay the 15 percent surcharge despite their zero-MFN preference.

This guide explains the calculation, the KORUS qualification rules, and worked examples. The calculator handles the stack.

The duty layers for South Korea to USA

For a typical KORUS-qualifying Korean entry in 2026:

1. KORUS preferential rate (typically 0 percent) replaces MFN HTS.
2. Section 122 at 15 percent on most lines, unless the HTS is on the March 2026 carve-out list (semiconductors, EV batteries, certain pharma APIs).
3. Section 232 at 25 percent on steel and aluminum, with the Korean TRQ arrangement.
4. MPF and HMF.
5. No Section 301.

For non-qualifying Korean goods (e.g., transshipped Chinese product with insufficient Korean transformation), MFN plus 15 percent Section 122 applies as if no FTA existed.

KORUS qualification

KORUS uses a tariff-shift rule (and in some cases regional value content) similar to USMCA but with Korea-specific specifics. To claim:

1. The good must satisfy the product-specific rule of origin in KORUS Annex 4-A.
2. A KORUS certificate of origin must be on file. The certificate can be self-certified by the producer, exporter, or importer. No prescribed form, but must include 12 specified data elements.
3. The importer claims preference on the entry summary with SPI code KR or as required by current CBP guidance.
4. Records must be retained for five years.

Random audits do happen. CBP penalty under 19 USC 1592 applies to false claims.

Worked example: 5,000,000 USD of Korean semiconductors

A Korean fab ships memory chips to a US distributor. Total invoice 5,000,000 USD CIF, including 30,000 USD air freight and 12,000 USD insurance (semiconductors typically ship air). HTS 8542.32 (memory ICs), MFN 0 percent under WTO ITA. KORUS does not change the 0 percent baseline.

The March 2026 amendment exempts semiconductors from Section 122.

Semiconductors are the cleanest possible case in 2026. Korean memory chips enter the US essentially duty-free.

Worked example: 800,000 USD of automotive parts (not exempt)

A Korean auto parts maker ships brake assemblies for installation in US-assembled vehicles. Total invoice 800,000 USD FOB Busan, 14,000 USD ocean freight to Long Beach, 3,200 USD insurance. HTS 8708.30 (brakes and parts), KORUS preference rate 0 percent. The category is not on the Section 122 carve-out list.

KORUS saves zero versus the MFN rate of 2.5 percent for auto parts (so 20,000 USD on a typical pre-122 calculation), but Section 122 dominates the bill at 120,000 USD. Effective duty rate 15.2 percent of FOB.

Run your own numbers in the calculator.

High-traffic HS chapters for South Korea to USA

Chapter 85: electronics

Memory chips, displays, mobile devices, white goods. Most lines 0 percent MFN under ITA. Many but not all exempt from Section 122 under the March 2026 carve-out. Display panels (HTS 8528.59) are exempt; consumer appliances (HTS 8418, 8450, 8516) are not.

Chapter 87: vehicles and parts

Korean passenger vehicles (HTS 8703) KORUS 0 percent, plus 15 percent Section 122. Auto parts similar.

Chapter 39, 40: plastics and rubber

Korean specialty resins. KORUS 0 percent. Section 122 applies.

Chapter 27: petroleum and refined products

Korean refining is a major US import source. KORUS 0 percent on most refined products. Section 122 applies; energy carve-outs may apply.

Chapter 30, 29: pharma and organic chemicals

Generic and biosimilar APIs. KORUS plus WTO Pharm Agreement set MFN at 0. Many specific APIs are on the Section 122 exemption list.

Chapter 73 and 76: steel and aluminum

Steel quota under the 2018 arrangement allows 2.68 million tons annually duty-free. Over the quota, Section 232 at 25 percent.

Section 232 and the Korean TRQ

The original 2018 arrangement gave Korean steel a 2.68 million metric ton annual quota exempt from Section 232. The quota is allocated by product category. Over the quota: 25 percent ad valorem. The 2025 melt-and-pour rule applies; Korean-finished steel using non-Korean melt may not qualify for the quota.

Aluminum: no formal Korean TRQ; standard 25 percent Section 232 applies to non-exempt aluminum.

Anti-dumping orders on Korean goods

Active US AD/CVD orders against Korean exports include:

• Certain corrosion-resistant steel
• Cold-rolled steel
• Hot-rolled steel
• Welded line pipe
• Various carbon and stainless steel pipe
• Polyethylene terephthalate (PET) film

Producer-specific rates. Cash deposits required at entry.

Customs procedures

Standard US import procedures. For KORUS-claimed entries:

• KORUS certificate of origin on file (importer holds; not transmitted at entry).
• SPI code on entry summary.
• Records retained five years.

CBP can request the certificate and supporting records during post-entry verification.

How the calculator handles this lane

When you select Origin: South Korea and Destination: USA in the calculator:

1. Looks up KORUS preferential rate or MFN HTS.
2. Applies 15 percent Section 122, except for HTS on the March 2026 exemption list (semiconductors, EV batteries, certain pharma APIs).
3. Checks chapter 72, 73, 76 for Section 232 with Korean TRQ status.
4. Applies anti-stacking 232 vs 122.
5. Adds MPF and HMF.

Related guides

• Calculate Import Duty: Japan to USA
• Calculate Import Duty: Germany to USA
• Calculate Import Duty: Taiwan to USA
• What is Section 122? The 2026 Reciprocal Tariff Explained
• FTA Preferences: Saving 5-25% on Duty
• Pharma HS Codes and FDA Requirements

Run a South Korea to USA calculation in the calculator.