How to Calculate Import Duty Using an HS Code

A Vietnamese furniture exporter we talked to last quarter quoted a US buyer a landed price based on FOB cost plus freight nothing else, because nobody on the team had actually worked out the duty. The shipment cleared under a wood-furniture HTS line that picked up an extra sector-specific tariff on top of the standard rate, and by the time the invoice was final, almost the entire margin on a $40,000 order was gone. Nobody had done anything wrong on purpose; they just never calculated it before quoting.

Import duty isn't one flat percentage you can memorize and reuse. It depends on four things at once the exact HS/HTS classification, the customs value, the country of origin, and whichever additional tariffs happen to be stacked on that product right now and in 2026 that last part changes more often than most importers can keep track of. Once you've got those four pinned down, the multiplication itself takes ten seconds the part that trips people up is not missing one of them.

What Information Do You Need to Calculate Import Duty?

Before you can calculate anything, gather these five inputs:

• The HS/HTS code, classified to the full national length 6 digits internationally, but 10 digits for a US import (the HTS line, not just the heading). Duty rates are set at this full line, not at the 6-digit level.
• The customs (dutiable) value. In the US this is generally the transaction value the price actually paid or payable for the goods, on an FOB basis not the CIF value (price, freight and insurance) that many other countries use as their customs value base.
• Country of origin where the goods were produced or last substantially transformed, not simply where they were shipped from.
• Destination country's import regulations, since duty bases, rates, and any import VAT/GST differ by market.
• Any trade preference the shipment might qualify for an FTA, GSP-type program, or origin-based exemption that could lower or zero out the standard rate.

Have these five on hand and a duty calculation usually resolves in one pass instead of several rounds of guessing.

How Does an HS Code Determine the Duty Rate?

Every country publishes a tariff schedule that assigns a duty rate to each full-length national tariff line in the US, that's the Harmonized Tariff Schedule (HTS), maintained by the U.S. International Trade Commission. Two products can share the same 6-digit international subheading and still carry different rates once you get to the 8th, 9th, or 10th digit, because that's where a country splits a subheading by material, use, or size to apply a different rate.

This is exactly why an approximate classification isn't good enough for a duty calculation "coffee" or "furniture" gets you to the right chapter, but the actual rate lives at the full national code. If you haven't nailed the exact HTS line yet, that's the step to fix first (our HS code lookup guide walks through classifying a product to the full 6-digit subheading before you ever look up a rate).

Most tariff lines carry a general (MFN most-favored-nation) rate that applies by default, plus a separate, much higher "Column 2" rate reserved for a short list of countries the US doesn't extend normal trade relations to (currently Cuba, North Korea, Russia, and Belarus). For nearly every other trading partner, you start from the Column 1 general rate and then layer on anything origin-specific.

How to Find the Import Duty Rate by HS Code

Three practical ways to find the rate once you have the full HTS code:

1. USITC's HTS Search (hts.usitc.gov) the official, free source for the current published Harmonized Tariff Schedule and its general duty rate per line.
2. CBP's CROSS rulings database useful when your product sits close to a classification boundary and you want to see how CBP has ruled on similar goods before.
3. A tool that returns the rate directly from your product description instead of looking up the code, then separately looking up the rate, then separately checking whether any additional tariff applies to that country, a lookup tool that does all three in one query saves the step where most manual errors happen (mismatching a rate to the wrong revision of the code).

Whichever source you use, check the as-of date. The base HTS rate itself barely moves, but from late 2024 through mid-2026 the US layered and re-layered several country- and sector-specific surcharges on top of it memorizing last quarter's total rate is a common way importers under-quote a shipment today.

How to Calculate Import Duty Step by Step

The core formula is simple; getting every input right is where the work is:

Import duty = Customs value × Applicable duty rate (plus any specific or compound-duty component, plus any additional tariff that stacks on top).

1. Classify the product to the full national HTS/HS code.
2. Establish the customs value transaction value on an FOB basis for a US import (confirm the correct value basis if you're importing into a market that uses CIF instead).
3. Confirm the country of origin the country of substantial transformation, which can differ from the country you're shipping from.
4. Look up the base (Column 1 general) rate for that exact HTS line it may be ad valorem (a %), specific (a fixed amount per unit/weight), or compound (both).
5. Check for additional, origin- or sector-specific tariffs that stack on top of the base rate for that product and country this is the step most manual calculations skip, and it's the one that moves the total the most right now.
6. Check FTA or preference-program eligibility a qualifying origin can reduce the base rate to a preferential rate or to zero, if you can document the rule of origin.
7. Multiply and sum: customs value × base rate, plus any specific-duty amount, plus any stacked surcharge, gives total duty owed.
8. Add non-duty costs only if you're calculating full landed cost merchandise processing fee, harbor maintenance fee, freight, insurance, and any destination-country import VAT/GST (see the next section).

Why Country of Origin Changes the Duty Rate

Two identical products with the same HTS code can owe completely different duty depending on where they're from, for three separate reasons:

• FTA and preference programs. If a shipment qualifies under a free trade agreement's rule of origin (regional value content, tariff shift, or similar), the base rate can drop sometimes to zero but only with proper documentation. Skipping this check is one of the most common ways importers overpay.
• Column 2 punitive rates, which apply only to the small list of non-normal-trade-relations countries mentioned above.
• Country-specific stacked tariffs. Since 2018 the US has added several rounds of country- and product-targeted tariffs on top of the base rate (Section 301 actions, and more recently a forced-labor-linked tariff applied at different rates across dozens of economies). These apply by country of origin, not country of shipment routing a shipment through a third country doesn't change the origin the tariff is assessed against.

Origin also gets genuinely hard to pin down for products assembled from components sourced across several countries the origin is wherever the last substantial transformation happened, which is a legal test, not just "where the factory is."

Additional Tariffs, VAT and Trade Remedies

Beyond the base HTS rate, a shipment can pick up several more charges depending on the product and market:

• Section 301/forced-labor and country-specific tariffs additional percentage points layered on top of the base rate for specific countries and product categories, changed multiple times through 2025-2026.
• Section 232 sector tariffs separate, often much higher rates applied by industry (steel, aluminum, automobiles and parts, and a few other sectors have carried significantly elevated rates through 2026), regardless of country of origin.
• Antidumping and countervailing duties (AD/CVD) case-specific duties on a named product from a named country found to be dumped or subsidized; these can run into triple digits and are calculated separately from the standard HTS rate.
• Import VAT/GST not a US mechanism (the US has no federal import VAT), but most other markets charge VAT or GST on the customs value plus duty, which is a different math than a US-only calculation.
• De minimis status. This one changed materially in 2026: the long-standing $800 duty-free exemption for low-value shipments (Section 321) was suspended indefinitely as of June 24, 2026, across essentially all import modes. If your calculations still assume small parcels clear duty-free under $800, that assumption is no longer safe check current status before quoting low-value ecommerce shipments.

None of these move in isolation from the base HTS rate they stack on top of it. Ask five importers what the duty on a product actually is and you'll often get five different answers, because each one stopped adding at a different layer

Example of Calculating Import Duty Using an HS Code

Figures below are an illustrative example only always confirm the live rate for your product and shipment date before filing; the mechanics of the calculation are what matters here, not the exact percentages, which shift often in the current environment.

Say you're importing 500 liters of extra virgin olive oil from Spain to the US, HTS subheading 1509.20.20, with a customs value of $5,000 (FOB Spain)

The point of the table isn't the dollar figure it's the sequence: classify to the full HTS line first, price it on the correct customs-value basis, apply the base rate, then check what else is stacked on top for that specific origin, before you ever quote a landed price to a buyer.

How EximAgent Helps Check Tariffs by HS Code

Instead of running these steps separately across three different lookup sites, EximAgent handles the whole chain in one query:

1. Ask in plain language. Something like "what's the landed cost to import olive oil from Spain to the US" no need to already know the HTS code or which surcharges currently apply.

2. It classifies the product first. The same classification wizard used for HS code lookups confirms the exact subheading before pricing anything since, as covered above, the rate lives at the full code, not the general category.

3. It returns the current duty rate for that exact line and origin including whether any country- or sector-specific tariff is currently stacked on top, and whether an FTA or preference program applies rather than a number that was accurate last quarter.

4. It totals the landed cost customs value, duty, and applicable fees together so you get one figure to quote against, not three numbers to add up yourself.

Checking tariffs and duty by HS code is free on every EximAgent plan, including the free tier the same way HS classification is. Check the current duty rate for your product at hscode.eximagent.ai.

FAQ

How do I calculate import duty from an HS code? Classify the product to its full national HTS/HS code, establish the customs value (transaction value, generally FOB for US imports), confirm the country of origin, then apply the base rate for that exact line plus any additional tariff currently stacked on that product and origin.

Is import duty calculated on FOB or CIF value? For US imports, duty is generally calculated on the FOB transaction value the price paid or payable for the goods themselves. Many other countries use CIF (which adds freight and insurance) as the customs value base, so the same shipment can be priced differently depending on the destination market.

What's the difference between import duty and VAT? Import duty is a tariff assessed on the customs value of the goods themselves under the HTS/HS classification. VAT (or GST) is a separate consumption tax some countries charge on top of the customs value plus duty. The US has no federal import VAT, but most other major import markets do.

Does country of origin affect the duty rate? Yes, significantly. Origin determines whether an FTA preference lowers the rate, whether a country-specific tariff stacks on top of it, or for a short list of countries whether the much higher Column 2 rate applies instead of the standard rate.

Do small shipments still get a duty-free exemption? No, and this is the change that's caught the most people off guard this year. The $800 de minimis exemption. (Section 321) was suspended indefinitely as of June 24, 2026, across nearly all import modes low-value shipments that used to clear duty-free now go through normal entry and duty assessment.

Is there a free tool to check import duty by HS code? Yes EximAgent's HS classification and tariff/duty lookup are free on every plan; only the detailed buyer-list feature for a given HS code sits behind a paid plan.

Try It on Your Own Product

Calculating import duty by hand across five inputs and a stack of country-specific surcharges is exactly the kind of thing worth checking rather than assuming a single missed surcharge can erase the margin on an order before it ships. Check the HS code and current duty rate for your product at hscode.eximagent.ai FREE, with the reasoning shown, not just a number.