Calculate Import Duty: Mexico to USA

Mexico is the United States' largest trading partner by total goods value as of 2026. The US-Mexico-Canada Agreement (USMCA, in force since 1 July 2020) eliminates tariffs on the vast majority of qualifying goods. Critically, the February 2026 Section 122 proclamation exempts USMCA-originating goods from the 15 percent reciprocal tariff, making qualified Mexican-origin goods the most tariff-favored sourcing option for the US market.

This guide explains the calculation, the USMCA origin rules, and a worked example. The calculator handles the qualification check automatically.

The duty calculation for Mexico to USA

For a typical Mexico to USA entry in 2026:

1. If the goods qualify under USMCA, MFN duty is 0 percent and Section 122 does not apply. You pay only MPF (0.3464 percent capped 614.35 USD) and HMF (0.125 percent sea cargo).
2. If the goods do not qualify under USMCA but are of Mexican origin (substantial transformation in Mexico), you pay the MFN HTS rate plus the 15 percent Section 122 surcharge.
3. Section 232 on steel and aluminum derivatives applies regardless of USMCA qualification, with melt-and-pour origin tracking.
4. Section 301 never applies to Mexican-origin goods (it is China-specific).

The split between qualifying and non-qualifying Mexican goods is the central question. Get it right and your effective duty drops to near zero. Get it wrong and you owe MFN plus Section 122 plus penalties under 19 USC 1592.

USMCA origin qualification

A good qualifies under USMCA if it meets one of three pathways:

1. Wholly obtained or produced entirely in the territory of one or more USMCA parties. Think mined minerals, agricultural products grown in the territory, fish caught in territorial waters.
2. Produced entirely in the territory of one or more parties exclusively from originating materials. All inputs are themselves USMCA-originating.
3. Produced entirely in the territory using non-originating materials, provided each non-originating material undergoes the applicable tariff classification change and any applicable regional value content requirement.

The product-specific rule of origin (PSRO) is in USMCA Annex 4-B. Look up your eight-digit HTS to see whether the rule requires a tariff shift (typically CTH or CTSH), an RVC, or both.

RVC: transaction value vs net cost method

Two methods exist:

• Transaction value method: RVC = (Transaction Value - Value of Non-Originating Materials) / Transaction Value, expressed as a percentage. Threshold typically 60 percent.
• Net cost method: RVC = (Net Cost - Value of Non-Originating Materials) / Net Cost. Threshold typically 50 percent.

For automotive products the net cost method is mandatory and the threshold is higher (75 percent on light vehicles, with staged labor value content and steel/aluminum requirements).

Automotive: the toughest rules

Light vehicles and core auto parts have layered USMCA rules:

• Regional value content of 75 percent (net cost) on light vehicles.
• Labor value content of 40 percent for light vehicles and 45 percent for trucks, with at least 25 percentage points coming from high-wage materials and manufacturing (minimum 16 USD/hour).
• Steel purchasing: at least 70 percent of steel by value purchased in North America must originate in North America (melt-and-pour test in 2026 onwards).
• Aluminum purchasing: same 70 percent rule.

These rules ratcheted up between 2020 and 2025; by 2026 the full thresholds are in effect. Many vehicles that qualified under NAFTA do not automatically qualify under USMCA.

Section 122 exemption for USMCA goods

The February 2026 Section 122 proclamation contains a specific carve-out: "Goods of Canada and Mexico that originate under USMCA shall not be subject to the additional 15 percent duty under this proclamation."

Note the conditional: originate under USMCA. A Mexican-origin good that is not USMCA-qualifying does still pay the 15 percent Section 122. The exemption is tied to FTA qualification, not to country of origin alone.

In practice this means many Mexican factories that previously imported from Asia, assembled in Mexico, and re-exported as Mexican-origin under simple substantial transformation now have to genuinely meet the USMCA tariff-shift and RVC tests to avoid the 15 percent. The 2026 stack changed the economics of light-assembly in Mexico significantly.

Worked example: 200,000 USD of automotive wire harnesses

You are importing 5,000 wire harnesses for passenger vehicles from a maquiladora in Ciudad Juarez. HTS 8544.30 (ignition wiring sets for vehicles). MFN rate 5 percent. The harnesses qualify under USMCA based on the product-specific rule (CTH from non-originating components, RVC 60 percent transaction value).

If you sourced the same parts from China you would pay:

The Mexico USMCA option saves 90,250 USD per container. This is why so much Asian-sourced supply chain has been reshoring to Mexico since 2020.

Try this with your own numbers in the calculator.

Section 232 on Mexican steel and aluminum

The melt-and-pour origin rule introduced in 2025 means Section 232 follows the country where the steel was originally melted and poured, not where the final article was fabricated. A Mexican-finished steel article using Chinese melt steel is still subject to Section 232 at 25 percent.

This caught many Mexican fabricators off guard. To avoid Section 232, fabricators must source melt from North America and document it via mill test reports back to the original melt source. The required certification is a producer affidavit listing the melt mill, country, and heat number.

High-traffic HS chapters for Mexico to USA

• Chapter 87 (vehicles and parts): USMCA-eligible if the automotive RVC and LVC thresholds are met. The big save in 2026.
• Chapter 85 (electrical machinery): most lines USMCA-eligible with CTH/RVC. Includes consumer electronics finished in Mexican plants.
• Chapter 84 (machinery): similar to chapter 85.
• Chapter 39 (plastics): typically eligible. Tariff shift rule.
• Chapter 73 (steel articles): USMCA does not exempt from Section 232. Melt-and-pour origin matters.
• Chapter 22 (alcoholic beverages): tequila and mezcal must meet origin rules; geographic indication protected.
• Chapter 8 (fresh fruit and vegetables): typically wholly obtained; zero duty.

Common pitfalls for Mexican-origin entries

• Failing to maintain origin certifications: USMCA requires the certifier to keep supporting records for five years after the date of certification. Random audits do happen.
• Misapplying transaction value method when net cost is required: automotive in particular.
• Forgetting melt-and-pour for Section 232: a producer affidavit is now standard practice.
• Using "ships from" as evidence of origin: shipping out of a Mexican port does not establish Mexican origin. Substantial transformation in Mexico does.
• De minimis confusion: Mexico-to-USA still has 800 USD de minimis under 19 USC 1321. Many Mexican ecommerce sellers use it.

How the calculator handles this lane

When you select Origin: Mexico and Destination: USA in the calculator:

1. Asks whether the goods qualify under USMCA (or you confirm with the qualification helper).
2. If qualifying, applies zero MFN and skips Section 122.
3. If not qualifying, applies MFN HTS plus 15 percent Section 122.
4. Checks chapter 72/73/76 against Section 232 with melt-and-pour origin asked.
5. Adds MPF.

Related guides

• USMCA Origin Rules: What Qualifies and What Doesn't
• What is Section 122? The 2026 Reciprocal Tariff Explained
• Section 232 vs 301 vs 122: How US Tariffs Stack in 2026
• Steel HS Codes Under Section 232
• FTA Preferences: Saving 5-25% on Duty
• Calculate Import Duty: China to USA

Run a Mexico-to-USA number in the calculator.