How to Calculate Customs Tariff Duty
What is Customs Tariff Duty?
The Customs Tariff Duty Calculator determines the exact import duty owed on goods entering a country by looking up the Harmonized Tariff Schedule (HTS) code and applying the corresponding ad valorem, specific, or compound duty rate to the declared customs value.
Formula
- CV
- Customs Value ($) — Declared transaction value of imported goods including adjustments
- R
- Ad Valorem Rate (%) — Percentage duty rate from the HTS schedule
- S
- Specific Rate ($/unit) — Fixed duty amount charged per unit of measure
- Q
- Quantity (units) — Number of units imported in the applicable unit of measure
Step-by-Step Guide
- 1Classify your product using the correct 8-10 digit HTS code
- 2Look up the applicable duty rate (general, special, or column 2) for the HTS code
- 3Calculate the customs value (transaction value + assists + packing costs)
- 4Multiply the customs value by the ad valorem percentage and add any per-unit specific duties
Worked Examples
Common Mistakes to Avoid
- ✕Using the wrong HTS code, which can change the duty rate dramatically
- ✕Forgetting to include freight and insurance in the customs value for CIF countries
- ✕Not checking whether a preferential rate applies under a free trade agreement
Frequently Asked Questions
What is the difference between ad valorem and specific duty?
Ad valorem duty is a percentage of the goods value (e.g., 5%), while specific duty is a fixed amount per unit (e.g., $0.50 per kilogram). Some goods have compound duties combining both.
How do I find the correct HTS code for my product?
Use the USITC HTS search tool at hts.usitc.gov, consult a licensed customs broker, or request a binding ruling from CBP for certainty.
Does customs duty apply to samples or gifts?
Generally yes, unless the shipment qualifies under the de minimis threshold ($800 in the US) or falls under a specific exemption for bona fide samples of negligible value.
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