Reading HTS Tariff Schedules

The Three Rate Columns

Every tariff line in the HTS has three rate columns. Understanding which column applies to your import is the first and most critical step in determining what you will pay.

For the vast majority of imports, you will pay the General rate. Special rates require documentation proving the product qualifies under a specific trade agreement — including rules of origin certification from the exporting country. Browse HTS chapters to see rate columns for any product category.

Types of Duty Rates

Not all tariff rates are simple percentages. The HTS uses three types of rate structures, and understanding the difference is essential for calculating what an import will actually cost:

• Ad valorem rates — A percentage of the declared customs value. Example: "5%" means you pay 5% of the product's transaction value. This is the most common type and the easiest to understand. If you import $100,000 worth of goods at a 5% ad valorem rate, the duty is $5,000.
• Specific rates — A fixed amount per unit of quantity. Example: "3.5¢/kg" means you pay 3.5 cents for every kilogram imported, regardless of the product's value. Specific rates are common in agricultural commodities, beverages, and tobacco. They can be regressive — a cheap product pays the same per-unit duty as an expensive one.
• Compound rates — A combination of ad valorem and specific components. Example: "10% + 2¢/kg" means you pay both a percentage of value and a per-unit charge. Compound rates appear frequently in processed foods, textiles, and chemicals. To calculate the total duty, you must compute both components separately and add them.

Some tariff lines show "Free" — meaning no duty is assessed. About 30% of HTS lines carry a General rate of Free. Others show a rate followed by "but not less than X%" or "but not more than Y%" — these are floor and ceiling provisions that bound the effective rate.

Tariff Rate Quotas: Two Rates for One Product

Some of the most protected US industries use tariff rate quotas (TRQs) — a system where a limited quantity of imports enters at a low rate, and anything above that quantity faces a much higher rate. TRQs exist for sugar, dairy, beef, cotton, peanuts, tobacco, and certain other agricultural products.

The economics are significant. Raw cane sugar has an in-quota rate of approximately 1.5 cents per pound (roughly equivalent to a 2-3% ad valorem rate). The over-quota rate is approximately 15 cents per pound — ten times higher. This effectively limits sugar imports to the quota amount, supporting domestic sugar prices well above world market levels.

Quota allocations are typically distributed among exporting countries based on historical trade patterns. The USDA and CBP administer quota tracking. Once a country's allocation is filled, additional imports from that country pay the over-quota rate. You can see which HTS sections contain TRQ products by browsing the agricultural chapters (1-24).

Section and Chapter Notes: The Legal Fine Print

Every HTS section and chapter begins with legal notes that define what is included, excluded, and how classification conflicts are resolved. These notes are not optional reading — they are legally binding and take precedence over the product descriptions in headings and subheadings.

Common note types include:

• Exclusion notes: "This chapter does not cover..." — directing certain products to a different chapter.
• Definition notes: "For the purposes of this chapter, 'stainless steel' means..." — providing legally precise definitions.
• Priority notes: "Goods classifiable under two or more headings shall be classified under the heading that provides the most specific description" — resolving ambiguity.
• Additional US notes: Notes specific to the US implementation, often detailing TRQ administration, seasonal rates, or country-specific provisions.

Classification disputes often hinge on note interpretation. A product that appears to fit in one chapter may be explicitly excluded by a chapter note and directed to another. Always read the notes before relying on a product description match.

Additional Duties Beyond the Base Rate

The rate shown in the HTS is not always the final duty. Several types of additional duties can apply on top of the base rate:

• Section 301 duties: Additional tariffs imposed under trade dispute authority. The US-China Section 301 tariffs added 7.5% to 25% on top of base HTS rates for thousands of Chinese products. These are listed in HTS Chapter 99.
• Section 232 duties: National security tariffs. Steel (25%) and aluminum (10%) imports from most countries face Section 232 duties above their base HTS rate.
• Antidumping and countervailing duties (AD/CVD): Product-specific and country-specific duties imposed when foreign goods are sold below fair market value (dumping) or subsidized by foreign governments. AD/CVD rates can exceed 100% for some products.
• Merchandise Processing Fee: A 0.3464% ad valorem fee on most formal entries (minimum $31.67, maximum $614.35).
• Harbor Maintenance Fee: 0.125% of the value of cargo imported through US ports.

See our guide on US tariff impact for how these additional duties affect specific product categories.

Practical Framework: Looking Up a Tariff Rate

When you need to determine the duty rate for an import, follow this sequence:

1. Identify the product and its materials, construction, and intended use.
2. Search or browse PlainTariff to find potential HTS codes. Start at the chapter level and narrow down.
3. Read the section and chapter notes to confirm the product belongs in that classification.
4. Check all three rate columns: General, Special, and Column 2. Determine which applies based on country of origin.
5. Identify the rate type (ad valorem, specific, or compound) and calculate the duty amount.
6. Check for additional duties: Section 301/232, AD/CVD orders, and fees.
7. If the classification is uncertain, consider requesting a binding ruling from CBP. See our HTS code reading guide for detailed classification steps.

Worked Example: Importing Coffee From Colombia

Suppose you import 5,000 kg of roasted coffee (HTS 0901.21.00) from Colombia at a declared customs value of $35,000. Colombia has a US trade agreement (US-Colombia TPA), so you check both the General and Special rate columns.

The US-Colombia TPA saves $1,835.00 ... $3,835.01 on this shipment — that is 83% ... 91% in duty savings. Without the certificate of origin, you would owe the full compound rate plus fees. The lesson: always check the Special column before importing from an FTA partner country.

Common Rate Types by HTS Section

Different sections of the HTS favor different rate structures. Agricultural products (Sections I-IV) tend to use specific and compound rates, while manufactured goods (Sections VI-XVI) lean toward ad valorem rates.

Step-by-Step: Calculating a Compound Duty

Compound duties require computing both components separately. Here is how to calculate a compound rate of "6.4% + $0.09/kg" for an import of 10,000 kg of prepared tuna (HTS 1604.14.10) valued at $45,000:

1. Ad valorem component: $45,000 x 6.4% = $2,880
2. Specific component: 10,000 kg x $0.09/kg = $900
3. Total compound duty: $2,880 + $900 = $3,780
4. Effective ad valorem rate: $3,780 / $45,000 = 8.4% — higher than the stated 6.4% because the specific component adds a fixed cost regardless of value

This illustrates why reading only the percentage part of a compound rate understates the true duty burden. The specific component adds $0.09 per kg whether the tuna is cheap ($2/kg) or premium ($8/kg). For low-value goods, the specific component dominates; for high-value goods, the ad valorem component dominates.

Verifying Classification With Binding Rulings

If you are unsure which HTS code applies to your product, you can request a binding ruling from US Customs and Border Protection. A binding ruling is a written determination from CBP that confirms the correct HTS classification for your specific product. It is legally binding on CBP — meaning they cannot later reclassify the product and charge additional duties — as long as the product matches the description in your ruling request.

Binding rulings are free to request and typically take 30 days. You can also search CBP's database of previously issued rulings (CROSS) to see how similar products were classified. This is especially useful for new products, multi-component items, and goods that could plausibly fit under multiple HTS chapters.

Seasonal and Temporary Duty Modifications

Some HTS rates are modified temporarily through Chapter 99 provisions or presidential proclamations. These changes can create or eliminate duties for specific products, countries, or time periods. The USITC publishes the HTS with these modifications reflected, but they can change between publication dates. Always verify the current Chapter 99 provisions for any product subject to Section 301, Section 232, or other trade actions, as exclusions and modifications occur frequently.

Frequently Asked Questions