How to Calculate Import Duties for E-commerce: Landed Cost Formula & Practical Examples (2026)

For e-commerce sellers importing products into the United States, calculating the true landed cost — the total cost to get goods from the foreign supplier to your warehouse door — is essential for pricing, profitability, and compliance. Underestimating import duties is one of the top reasons e-commerce businesses fail: a product that appears profitable at the wholesale price can become unprofitable once all import costs are included. This guide breaks down the landed cost formula step by step with real examples.

The Landed Cost Formula

Landed cost = Product cost + Freight + Insurance + Customs duty + Merchandise processing fee (MPF) + Harbor maintenance fee (HMF) + Broker fees + Additional duties (Section 301, ADD/CVD)

Each component must be calculated correctly:

1. Product Cost (Customs Value)

The customs value is the price actually paid or payable for the goods when sold for export to the US, per 19 USC §1401a (Transaction Value). This is typically the FOB price from your supplier. Key adjustments:

• Add: Selling commissions paid to the supplier's agent, royalties/license fees the buyer must pay as a condition of sale, assists (materials/tools/engineering the buyer provided to the supplier free or at reduced cost)
• Do NOT add: Freight after importation (inland freight to your warehouse), US customs duties, US taxes

E-commerce gotcha: If you pay your Chinese supplier $5 per unit FOB Shanghai, but you also pay a 5% royalty to a US brand licensor, your customs value is $5.25 per unit — the royalty must be included. Many e-commerce sellers miss this.

2. Freight

International freight (ocean, air, or courier) from the foreign port to the US port of entry. This is NOT included in the customs value for duty calculation under FOB terms. Under CIF terms (rare for US imports), freight IS included in the customs value.

3. Insurance

Marine/transport insurance. Small for most shipments (0.3-0.5% of value) but legally required to be included in the customs value if CIF valuation applies.

4. Customs Duty Calculation

Duty = Customs Value × Duty Rate. The duty rate comes from the HTS code classification at the 8-digit level.

Critical: Duty rates are ad valorem (percentage of customs value), not percentage of retail price. A product with $10 customs value and 5% duty rate has $0.50 duty per unit, regardless of whether you sell it for $30 or $100 retail.

5. Merchandise Processing Fee (MPF)

MPF = 0.3464% of the customs value, with a minimum of $31.75 and maximum of $614.35 (2026 rates). Applied to most formal entries (value >$2,500). MPF is NOT a duty — it is a user fee for CBP processing.

6. Harbor Maintenance Fee (HMF)

HMF = 0.125% of the value of the cargo arriving by vessel (ocean freight). Does NOT apply to air or courier shipments. Applied in addition to duty and MPF.

7. Additional Duties: Section 301, ADD/CVD

These are the costs that most commonly surprise e-commerce importers:

• Section 301: 25% additional duty on Chinese-origin goods (List 1-3), 7.5% for List 4A. Applied ON TOP of the normal duty rate. A product with 5% normal duty + 25% Section 301 = 30% total duty.
• Anti-Dumping (ADD): Product and country-specific. Ranges from 5% to over 200% for Chinese aluminum extrusions. Applied in addition to normal duty and Section 301.
• Countervailing (CVD): Similar to ADD but offsets foreign government subsidies.

De Minimis: The $800 Exemption

Section 321 (de minimis) allows duty-free entry for shipments valued under $800. However:

• Section 301 duties still apply to de minimis shipments — the $800 exemption covers normal duty only
• ADD/CVD may apply depending on the product
• The $800 threshold is per shipment, not per item or per day
• Marketplace facilitators (Amazon, eBay, Walmart) are required to collect and report import taxes on de minimis shipments per the Marketplace Facilitator Act

5 Worked Examples

Example 1: Bluetooth Speaker from China

• Customs value: $8,000 (FOB Shenzhen, 1,000 units at $8/unit)
• HTS: 8518.22.0000 — Duty rate: Free (Column 1 General)
• Section 301 List 3: 25% additional duty
• Freight (air): $600
• Calculation: $8,000 × 0% (normal) = $0 | $8,000 × 25% (Section 301) = $2,000 | MPF = $31.75 | Total duty = $2,031.75
• Landed cost per unit: ($8,000 + $600 + $2,031.75) / 1,000 = $10.63/unit

Example 2: Women's Cotton Dresses from Vietnam

• Customs value: $15,000 (FOB Ho Chi Minh City, 500 units at $30/unit)
• HTS: 6204.42.4010 — Duty rate: 13.2% (Column 1 General)
• No Section 301 (Vietnam not on Section 301 lists for this product)
• Freight (ocean): $1,200 | Insurance: $75
• Calculation: $15,000 × 13.2% = $1,980 | MPF = $51.96 | HMF = $18.75 | Total duty = $2,050.71
• Landed cost per unit: ($15,000 + $1,200 + $75 + $2,050.71) / 500 = $36.65/unit

Example 3: Stainless Steel Flatware from China

• Customs value: $20,000 (FOB Guangzhou, 10,000 sets at $2/set)
• HTS: 8211.92.0000 — Duty rate: Free
• Section 301 List 3: 25% additional duty
• ADD on Chinese stainless steel flatware: 54.2% (company-specific rate)
• Freight (ocean): $2,500 | Insurance: $100
• Calculation: $20,000 × 0% (normal) = $0 | $20,000 × 25% (Section 301) = $5,000 | $20,000 × 54.2% (ADD) = $10,840 | MPF = $69.28 | HMF = $25.00 | Total duty = $15,934.28
• Landed cost per unit: ($20,000 + $2,500 + $100 + $15,934.28) / 10,000 = $3.85/set
• Key lesson: ADD turned a $2 product into a $3.85 landed cost — 79.2% effective duty rate. This is why you MUST check ADD/CVD before sourcing from China.

Example 4: Phone Cases from China (De Minimis)

• Customs value: $750 (FOB Shenzhen, 500 units at $1.50/unit, shipped via courier)
• Below $800 de minimis threshold — normal duty waived
• Section 301 still applies: 25% on $750 = $187.50
• Total duty: $187.50
• Landed cost per unit: ($750 + $50 freight + $187.50) / 500 = $1.98/unit

Example 5: Power Tools from Taiwan (USMCA-eligible)

• Customs value: $50,000 (FOB Kaohsiung, 2,000 units at $25/unit)
• HTS: 8508.11.0000 — Duty rate: Free (Column 1 General for electric motor-driven hand tools)
• No Section 301 for Taiwan-origin goods
• Freight (ocean): $3,000 | Insurance: $250
• Calculation: $50,000 × 0% = $0 | MPF = $173.20 | HMF = $62.50 | Total duty = $235.70
• Landed cost per unit: ($50,000 + $3,000 + $250 + $235.70) / 2,000 = $26.74/unit
• Key lesson: Sourcing from non-Section-301 countries (Taiwan, Vietnam for non-covered products, USMCA region) dramatically reduces landed cost versus Chinese-origin equivalents.

Common E-commerce Duty Calculation Mistakes

1. Using retail price instead of customs value: Duty is calculated on the FOB/transaction value, not your selling price. A $50 retail item with $10 customs value has duty calculated on $10.
2. Forgetting Section 301: Over 60% of Chinese-origin consumer goods are subject to Section 301. This alone adds 7.5-25% to landed cost.
3. Ignoring ADD/CVD: Certain product categories (aluminum extrusions, steel pipe, wooden bedroom furniture, garlic, honey) have ADD rates of 50-300% on Chinese goods. Not checking ADD before sourcing is a six-figure mistake.
4. Per-unit de minimis abuse: Breaking a $5,000 shipment into 7 shipments of $714 to claim de minimis is illegal — CBP treats related same-day shipments as a single entry for de minimis purposes.
5. Not accounting for MPF and HMF: These fees add 0.35-0.47% to landed cost. Small individually, but material on large volumes.

Disclaimer: Duty calculations are for reference only and may not reflect all applicable trade remedies. Importers are responsible for verifying their own duty rates. PoliteDraft provides reference data only — not legal or trade compliance advice.