How to Calculate Your Total Import Duty in 2026

Most importers know they owe duty. Far fewer know exactly how much. The answer used to be simple — look up your HTS code, find the rate, multiply. In 2026, with multiple surcharges stacking on top of each other based on country and product, the real number is often two or three times what people expect.

This article walks through the full calculation, step by step, with five worked examples using real HTS codes and dollar amounts. By the end, you should be able to calculate the total duty on any shipment yourself.

The Formula

Here is the core equation:

Total Duty = Customs Value x (Base Rate + Section 301 + Section 232 + Section 122 + Fentanyl Duty)

Each term is a percentage. You add the applicable percentages together, then multiply by the customs value of the goods. Not all terms apply to every shipment — it depends on the product and where it was manufactured. But when multiple layers do apply, they stack. That is the part that catches people off guard.

Step 1: Determine Your Customs Value

The customs value is the number everything gets multiplied against, so getting it right matters.

For most imports, CBP uses the transaction value method: the price actually paid or payable for the goods when sold for export to the United States. In practice, this is usually the amount on your commercial invoice from the supplier.

Transaction value includes:

• The purchase price of the goods
• Packing costs borne by the buyer
• Any selling commission paid by the buyer
• The value of any assists (materials, tools, or engineering the buyer supplied to the manufacturer)

Transaction value does not include international freight or insurance — those are added separately for your landed cost calculation, but they are not part of the customs value for duty purposes.

If CBP rejects your transaction value (for example, because the buyer and seller are related parties and the price looks artificial), they apply alternative methods in a fixed order. For 95%+ of imports, the invoice price is the customs value.

Step 2: Find Your HTS Code and Base Rate

Every product imported into the US has a Harmonized Tariff Schedule code. The 8-digit code determines your base duty rate — the Column 1 General (MFN) rate that applies before any surcharges.

You can find your HTS code by:

1. Searching the USITC HTS database by keyword or product description
2. Using TariffDesk's HTS lookup tool, which shows the base rate plus all active surcharges in one view
3. Asking your customs broker, who classifies products for a living

Base rates range from Free (many electronics, raw materials) to 25%+ (textiles, footwear, some agricultural products). The spread is enormous, and a single digit in the HTS code can swing your rate by 15 percentage points.

Related reading: How to Find Your HTS Code

Step 3: Determine Country of Origin

Country of origin is the single biggest variable in your total duty calculation, because it determines which surcharges apply.

Country of origin means where the goods were substantially transformed — not where they were shipped from, not where the components came from, but where the product took on its essential character. A Chinese-made product transshipped through Vietnam is still Chinese in origin.

CBP uses the country of origin printed on the goods or packaging, supported by the certificate of origin filed with your entry.

Step 4: Check Which Surcharges Apply

This is where you build the stack. For each surcharge, ask: does it apply to this product from this country?

Key interactions to watch:

• Section 232 and Section 122 do not stack. If your product is subject to Section 232 (steel, aluminum, copper), it is exempt from the 10% Section 122 surcharge.
• Section 301 and Section 232 do stack on Chinese steel, aluminum, and copper products.
• USMCA-qualifying goods from Canada and Mexico are exempt from both Section 122 and base MFN duties. But Section 232 still applies to steel, aluminum, and copper regardless of USMCA status.

Related reading: Section 301 Tariffs Explained | Section 232 Tariffs: Steel, Aluminum, and Copper | Section 122 Tariff Explained

Step 5: Add It All Up

Once you know the customs value, the base rate, and which surcharges apply, the math is straightforward addition and multiplication. Here are five real examples.

Example 1: $50,000 of Cotton Shirts from China

HTS 6105.10.00 — Men's cotton knit shirts

Duty owed: $50,000 x 74.7% = $37,350

Your $50,000 shipment of shirts costs $87,350 before it even leaves the port. The surcharges alone — 301, 122, and fentanyl — add $27,500 on top of the $9,850 base duty.

Example 2: $25,000 of Steel Pipe Fittings from China

HTS 7307.93.30 — Stainless steel butt-welding fittings

Duty owed: $25,000 x 100% = $25,000

You pay the value of the goods again in duties. The Section 232 rate alone is $12,500. Note that Section 122 does not apply here because the product is already subject to Section 232 — but Section 301 and the fentanyl duty still stack.

Example 3: $10,000 of Electronics from Vietnam

HTS 8471.30.01 — Portable automatic data processing machines (laptops)

Duty owed: $10,000 x 10% = $1,000

Vietnam currently faces only the 10% global baseline. This is the simplest case — but watch this space. Vietnam is under active Section 301 investigation, and country-specific surcharges of 25-46% could take effect by mid-2026.

Example 4: $30,000 of Auto Parts from Mexico (USMCA)

HTS 8708.99.81 — Motor vehicle parts, other

Duty owed: $0

This is the power of USMCA. If the auto parts meet the agreement's rules of origin — including the 75% regional value content requirement for automotive goods — they enter duty-free with no surcharges. The certificate of origin is the key document here.

Related reading: USMCA Rules of Origin Explained

Example 5: $5,000 of Copper Wire from China

HTS 7408.11.30 — Refined copper wire, cross-section > 6mm

Duty owed: $5,000 x 98% = $4,900

A $5,000 purchase becomes a $9,900 landed cost before you even add shipping. Copper from China is one of the most heavily taxed product-country combinations in 2026, because Section 232 (50%), Section 301 (25%), and the fentanyl duty (20%) all stack on top of the base rate.

Beyond Duties: Fees That Add to Your Landed Cost

Duties are the biggest cost, but they are not the only cost. CBP and other agencies collect additional fees on every import:

Merchandise Processing Fee (MPF)

• Rate: 0.3464% of customs value
• Minimum: $31.67 per entry
• Maximum: $614.35 per entry
• Applies to nearly all formal entries

Harbor Maintenance Fee (HMF)

• Rate: 0.125% of customs value
• Applies to goods arriving by ocean vessel
• No cap

Customs Broker Fees

• Typically $150-$250 per entry for standard shipments
• Complex entries (multiple HTS codes, special programs) can run $400+
• Most brokers also charge for additional services like ISF filing ($50-$75), duty payment processing, and compliance review

Your True Landed Cost

Here is the full picture of what an import actually costs:

Landed Cost = Product Cost + International Shipping + Insurance
            + Duties + MPF + HMF + Customs Broker Fee
            + Domestic Freight to Warehouse

Using Example 1 — $50,000 of cotton shirts from China — a realistic landed cost breakdown looks like:

That is 1.85x the product cost. Almost half of your landed cost is duties and fees. If you quoted a customer based on the $50,000 product cost without calculating landed cost first, you are losing money.

Common Mistakes

Forgetting that surcharges stack. The most expensive mistake. Importers who budget for the 19.7% base rate on Chinese textiles and don't account for the additional 55% in surcharges are off by a factor of four.

Using FOB price instead of transaction value. If your purchase terms include packing, commissions, or assists, those add to the customs value. Understating customs value is a compliance violation with real penalties.

Not checking for surcharge exemptions. Section 232 products are exempt from Section 122. USMCA goods are exempt from both. Missing an exemption means overpaying.

Ignoring the MPF cap. On high-value shipments, the MPF caps at $614.35 — it does not keep scaling at 0.3464%. This means consolidating multiple small shipments into one larger entry can save money.

Not recalculating when rates change. Tariff rates moved multiple times in 2025-2026. A duty estimate from three months ago may be wildly wrong today. Always verify current rates before committing to a purchase order.

Calculate Your Rate in Seconds

You do not need to do this math by hand every time. Enter your HTS code into TariffDesk and see the base rate, all applicable surcharges, and the total effective rate for any country of origin — with the dollar impact calculated for your shipment value.

Look up your HTS code and see the total effective rate → TariffDesk

Related Articles

• The Complete Guide to US Import Tariffs in 2026
• How to Find Your HTS Code
• Section 301 Tariffs Explained
• Section 232 Tariffs: Steel, Aluminum, and Copper
• Section 122 Tariff Explained
• USMCA Rules of Origin Explained

Last updated April 8, 2026. Tariff rates change frequently — always verify current rates before making purchasing decisions.

Want automatic alerts when your rates change? Monitor your HTS codes with TariffDesk →