Bottom line: US import tariffs = FOB value × (MFN base rate + existing China 301 + Forced Labor 301 of China 12.5% added on 2026-07-24 + Section 232 + MPF/HMF fees). Each layer is calculated on FOB (Free On Board), not on CIF which includes freight and insurance.
The US does not impose a single tariff rate. Instead, multiple layers are stacked. For Chinese goods, common layers include:
| Layer | What it is | How it's calculated |
|---|---|---|
| MFN (Most Favored Nation) | WTO baseline duty | FOB × base rate |
| Existing Section 301 | Country-specific tariff on China (since 2018) | FOB × 301 rate (7.5%–25%) |
| Forced Labor Section 301 | New as of 2026-07-24, China 12.5% | FOB × 12.5%, stacks on the existing 301, does not stack with 232 |
| Section 232 | National security tariff on steel/aluminum/copper | FOB × 232 rate (50% for steel/aluminum) |
| Temporary reciprocal tariff | Expired Section 122 (10%), succeeded by the new 301 | FOB × corresponding rate |
| AD/CVD | Anti-dumping / Countervailing duties | Per case determination |
| MPF | Merchandise Processing Fee | FOB × 0.3464% (min $31.67, max $614.35) |
| HMF | Harbor Maintenance Fee | FOB × 0.125%, ocean freight only |
US Customs uses Transaction Value = FOB as the basis for calculating duties. This means international freight and insurance are NOT included in the taxable value.
This differs from China and the EU, which use CIF (Cost, Insurance, and Freight) as the tax base. So the same shipment is taxed on a different base depending on the country. The "value" field in HSBot's calculator refers to FOB.
Assume a shipment of Chinese-made wooden chairs, FOB value $10,000, ocean freight:
| Item | Calculation | Amount |
|---|---|---|
| MFN (wooden chairs often 0%) | $10,000 × 0% | $0 |
| Existing Section 301 (List 3, ~25%) | $10,000 × 25% | $2,500 |
| Forced Labor Section 301 (China 12.5%, new 2026-07-24) | $10,000 × 12.5% | $1,250 |
| Section 232 (not applicable to wood) | $10,000 × 0% | $0 |
| MPF | $10,000 × 0.3464% | $34.64 |
| HMF (ocean) | $10,000 × 0.125% | $12.50 |
| Total duties | $3,797.14 |
Effective rate = Total duties ÷ FOB = $3,797.14 ÷ $10,000 ≈ 37.97%
Figures are illustrative. Actual rates depend on your specific HS code and applicable lists. Use HSBot for real-time calculations.
Effective rate = (Duties + Additional duties + MPF + HMF) ÷ FOB value
Note: You cannot simply add up the percentage rates. Because MPF/HMF are fixed-percentage fees, the effective rate fluctuates slightly with the value structure.
Q: Are US tariffs calculated on CIF? A: No. The US uses FOB (excluding freight and insurance) as the tax base; China and the EU use CIF.
Q: What is the current Section 301 tariff on Chinese goods? A: The existing China 301 ranges from 7.5% to 25% by list, implemented in 2018 and still in effect. In addition, on 2026-07-24 the US added a Forced Labor 301 of China 12.5%, stacked on top of the existing 301 and not stacking with 232. The exact rate depends on your HS code's list.
Q: Does air freight require HMF? A: No. HMF only applies to ocean freight. Air shipments save 0.125%.
Q: How do I quickly calculate total tariffs for a shipment? A: Use the HSBot tariff calculator: enter your HS code and FOB value, and it automatically stacks MFN/existing 301/Forced Labor 301/232/MPF/HMF and totals the shipment.
HSBot uses official customs data. Enter a product name or HS code to auto-match the code, stack all applicable rates (including the Forced Labor 301 added on 2026-07-24), and compute total duties and effective rate. Supports US, China, and UK, with multi-HS shipment aggregation.