How to Calculate Import Duty: A Complete Guide for US Importers (2026)

Import duty in the US is not a single number — it is a stack of rates applied in sequence. Most importers only see the final CBP bill. This guide walks through each layer, explains what it is, and shows you how to calculate the total before your shipment arrives.

Step 1 — Find your HTS code

Every calculation starts with the correct 10-digit Harmonized Tariff Schedule (HTS) code. The HTS code determines your MFN rate, your Section 301 eligibility, your Section 232 eligibility, and which ADD/CVD orders apply.

The first 6 digits are harmonized internationally. The last 4 digits are US-specific statistical suffixes. You need all 10 digits for an accurate duty rate — the first 8 can change the rate significantly between similar products.

Step 2 — Get the MFN base rate

The MFN (Most Favored Nation) rate — also called the Column 1 General rate — is the standard tariff the US charges all WTO member countries. It applies to virtually every import unless you qualify for a Free Trade Agreement (FTA) rate, which we cover in Step 6.

MFN rates vary enormously by product. Consumer electronics are often 0%. Apparel runs 12–32%. Footwear can hit 37.5%. Agricultural products vary widely. There is no shortcut — you need the actual HTS chapter rate for your product.

Duty is always calculated on the CIF value (Cost + Insurance + Freight to the US port of entry). This is the customs value. US law differs from some countries that use FOB — make sure you are using the right basis.

Step 3 — Add Section 301 (China origin only)

If your goods originate in China (or are substantially transformed in China), Section 301 trade remedies add an additional surcharge on top of MFN. The rate depends on which USTR list your HTS code falls on:

Section 301 applies on top of MFN — it is additive, not a replacement. A product with 5% MFN and 25% Section 301 has a combined base rate of 30% before any other surcharges.

Step 4 — Add Section 232 (steel and aluminum)

Section 232 of the Trade Expansion Act of 1962 authorizes tariffs on national security grounds. As of June 2025, Section 232 rates are 50% on steel and 50% on aluminum — doubled from the original 25%/10% rates in force since 2018.

Section 232 applies to steel mill products, aluminum mill products, and derivative articles as defined by the relevant proclamations. If you import steel or aluminum goods — from any country — verify whether Section 232 applies to your HTS code before assuming you are clear.

Step 5 — Add Section 122 (10% global surcharge)

Following the IEEPA ruling on February 20, 2026, Congress enacted Section 122 — a flat 10% temporary surcharge on all imports, from all countries, effective February 24, 2026. It expires around July 24, 2026 under the 150-day limit of Section 122 of the Trade Act of 1974.

Unlike Section 301, Section 122 is universal — it applies to China, Mexico, Brazil, the EU, and every other trading partner. USMCA and CAFTA-DR FTA-qualifying goods may have different treatment depending on FTA terms. Read our full Section 122 explainer for the detailed breakdown.

Step 6 — Check ADD/CVD (antidumping and countervailing duties)

Antidumping (ADD) and countervailing duties (CVD) are product- and country-specific tariffs imposed by the Commerce Department after injury investigations. They can be enormous — ranging from a few percent to several hundred percent — and are applied on top of every other rate.

ADD/CVD orders are case-specific. Steel, solar panels, wooden cabinets, mattresses, seafood, and hundreds of other products have active orders. Search the USITC and Commerce Department ADD/CVD database, or use The Tariff Desk to check active orders for any HTS code.

Step 7 — FTA savings (USMCA, CAFTA-DR, and other agreements)

If your goods qualify under a US Free Trade Agreement, you may be entitled to a reduced or zero MFN rate — and critically, MPF exemption. USMCA (Canada, Mexico) and CAFTA-DR (Dominican Republic, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica) are the two most relevant agreements for Florida importers given the state's trade corridors.

FTA benefits require a valid certificate of origin, and your goods must satisfy the Rules of Origin for the specific HTS chapter. The savings can be substantial: a USMCA-qualifying consumer product that would otherwise carry 5% MFN + $33.58 MPF instead pays 0% + $0 MPF.

Step 8 — Calculate MPF (Merchandise Processing Fee)

MPF is a CBP user fee charged on every formal entry (shipments over $2,500). The formula:

The minimum and maximum are adjusted annually. The current FY2026 values ($33.58 / $651.50) are higher than FY2025 ($32.71 / $634.62). If you are using old spreadsheets, update them.

The minimum hits on small shipments — a $5,000 entry calculates to $17.32 (0.3464% × $5,000), which is below the $33.58 floor, so you pay the minimum. The maximum caps on large entries — a $250,000 shipment calculates to $866, which exceeds $651.50, so you pay the cap.

Step 9 — Calculate HMF (Harbor Maintenance Fee)

HMF is 0.125% of the CIF value and applies to ocean shipments entering through a US port. Air freight is exempt. The calculation is straightforward — no minimum, no maximum. A $100,000 ocean shipment pays $125 in HMF.

Worked example: consumer electronics from China, Port of Miami

Let's run a full calculation for a real scenario: a 20-foot container of wireless headphones (HTS 8518.30.2000) from Shenzhen, arriving at Port of Miami, CIF value $80,000.

To get the full landed cost, add ocean freight, inland drayage, customs brokerage fees, and any warehousing costs. For Port of Miami, typical drayage runs $475–$650/container depending on destination.

Common mistakes that blow up your duty calculation

2026 quick reference — key rates and thresholds

Summary: your import duty checklist