How to Calculate Import Duty: Step-by-Step for 2026

Import duty isn't just one number — it's a stack of fees that add up fast. Here's how to calculate the real total cost of importing goods into the United States.

The Import Duty Formula

Let's break down each component.

Step 1: Determine Your Product Value

US Customs uses the transaction value — the price actually paid or payable for the goods. This typically includes:

• The purchase price of the goods (FOB or CIF)
• Packing costs
• Selling commissions paid by the buyer
• Any assists (materials/tools you provided to the manufacturer)

It does not include international freight or insurance if you're using FOB terms (most common for US imports). However, if you're using CIF terms, freight and insurance are included in the dutiable value.

Step 2: Find Your HTS Duty Rate

Every product has a specific duty rate determined by its HTS code. Use our HTS Code Lookup to find yours.

Duty rates come in three forms:

• Ad valorem — A percentage of the value (e.g., 5.3%)
• Specific — A fixed amount per unit (e.g., 2.5 cents/kg)
• Compound — A combination (e.g., 5% + 3 cents/kg)

Most products use ad valorem rates, which makes the math straightforward.

Step 3: Add Special Tariffs

On top of the base HTS rate, several additional tariffs may apply depending on the product and country of origin:

Section 301 Tariffs (China)

If importing from China, check if your product is on one of the four Section 301 tariff lists:

• Lists 1 & 2: +25%
• List 3: +25%
• List 4A: +7.5%

Section 232 Tariffs (Steel & Aluminum)

If importing steel or aluminum products:

• Steel (HTS chapters 72-73): +25%
• Aluminum (HTS chapter 76): +10%

Anti-Dumping / Countervailing Duties

Product-specific surcharges on goods sold below fair market value or subsidized by foreign governments. These can range from 5% to over 200%.

Step 4: Calculate MPF (Merchandise Processing Fee)

CBP charges an MPF on all formal entries (value > $2,500):

• Rate: 0.3464% of the product value
• Minimum: $31.67
• Maximum: $614.35

For informal entries (value ≤ $2,500), the fee is $2, $6, or $9 depending on entry type.

Step 5: Add HMF (Harbor Maintenance Fee)

If goods arrive by vessel (ocean freight), add the Harbor Maintenance Fee:

• Rate: 0.125% of the product value
• Applies to goods entering US ports by sea
• Does not apply to air freight or land border crossings

Real-World Example

That's $15,385 in duties and fees on a $50,000 shipment. If this product were sourced from Vietnam instead of China, the Section 301 tariff wouldn't apply — saving $12,500.

Try It Yourself

Use our free tariff calculator to calculate your specific landed cost. Or get a complete Tariff Audit Report showing your industry's highest-duty items and savings opportunities for $19.