US Section 301 Tariff Stacking Scenario Calculator

Compare costs before you ship

Enter only tariffs that legally apply to the product and date of entry. This tool does not assume Section 301, Section 232, or other surcharges automatically stack.

Do Section 301 and Section 232 tariffs always stack?

No. Some US import tariffs are additive, but federal notices and rules can exclude or supersede overlapping duties. Section 301 rates also depend on the precise HTS subheading and applicable exclusions, not just the exporting country. The calculator therefore starts the additional surcharge fields at zero and will only include the rates you enter.

Example of an entered-rate scenario

Assume a $10,000 customs transaction value, a 5% ordinary duty, and an additional 25% duty that you have verified applies. The duty estimate would be $500 plus $2,500, or $3,000, before separately assessed fees. Adding $1,000 freight and $150 in brokerage to the $10,000 goods value gives an illustrative $14,150 landed cash outlay. This example does not assert that a 25% rate applies to any particular shipment.

How to validate the tariff lines

First identify the product’s complete ten-digit HTSUS statistical reporting number. Then check Section 301 lists and exclusions, relevant Chapter 99 subheadings, country of origin rules, Section 232 measures and any anti-dumping or countervailing duty. Verify the import date because measures can expire or change. Some adjustments to transaction value also affect the customs base.

Official resources: USTR Section 301 product search and exclusions, USITC Harmonized Tariff Schedule, and CBP trade remedies. The tool does not replace customs classification advice.

Guide reviewed November 14, 2026. The examples below explain each input, underlying assumptions, and important commercial limitations.

Why a single ‘China tariff rate’ is unreliable

US customs duty depends on the actual tariff classification and where the article originates under applicable origin rules. Two products made in the same country may face different ordinary duty rates, separate trade remedy measures, and distinct exclusions. A product advertised as an electronic accessory, for example, could require more detailed classification than the marketing description suggests.

The current US Harmonized Tariff Schedule includes general and special duty columns as well as Chapter 99 provisions. An importer must check both the ordinary tariff line and any relevant additional lines. That is why this calculator begins with editable rates and makes no claim that Section 301, Section 232, or a broad country surcharge automatically applies to every shipment.

The difference between Section 301 and Section 232

Section 301 measures arise from US trade investigations and can apply to designated classes of products with particular origins and tariff numbers. Certain Section 301 exclusions or amendments change the charge due on specified merchandise. Section 232 measures relate to national security and can cover certain metals, derivatives, vehicles, parts, or other classes as identified by governing proclamations and annexes.

Whether two measures may be charged together is not as simple as adding every headline percentage in a news story. Some legal provisions establish overlapping-duty exceptions, exclusions, content-based treatment, or order-of-application rules. Enter only rates confirmed to be applicable simultaneously to your particular product, transaction and entry date.

Step-by-step classification and rate verification

First record the full commercial description, materials, function and intended use of the goods. Identify the ten-digit HTSUS statistical reporting number and verify the corresponding legal tariff classification. The internationally shared HS system begins with six digits, but the US tariff and statistical schedule is more detailed.

Next check the country of origin under the relevant rules, not simply the warehouse or shipping location. Read the active Chapter 99 headings and notices, including the appropriate Section 301 list, exclusions, and any Section 232 treatment. Review current CBP instructions and tariff-effective dates. Keep a dated record or broker calculation supporting each rate entered.

Worked example using explicitly assumed rates

Assume a shipment with a $10,000 customs value. Suppose the base MFN duty rate is 5% and a separate 25% Section 301 rate has been confirmed as applicable for that hypothetical article. The ordinary duty equals $500, and the added duty equals $2,500. The combined modeled duty is $3,000. This is a calculation example, not evidence that any named product or country currently has those rates.

If you then spend $1,000 on international freight and insurance and $150 on entry and brokerage services, the illustrated cash outlay becomes $14,150. If those services or costs are already included in your invoice, do not enter them twice. If an applicable additional duty is not ad valorem, enter the amount in the separate specific-duty field.

When ad valorem stacking is the wrong model

Some merchandise attracts a specific duty by unit, weight, or volume, or a compound duty combining a percentage and a specified amount. For other items, a Section 232 measure may assess only specified content or require a different valuation basis than the full customs value. Anti-dumping and countervailing duty deposits are also not necessarily reducible to a single guaranteed percentage.

The present tool is a scenario comparison with optional percentage fields and one separate amount field. It does not automate legal tariff stacking, determine aluminum or steel content values, or calculate final antidumping liability. More complex cases require line-by-line legal guidance, an official classification ruling or a licensed customs broker.

Pricing and compliance implications for importers

An extra customs duty can affect gross margin, working capital, customs bond requirements, and the size of a shipment. For example, a 10-point increase in a duty rate applied to $50,000 in customs value can add $5,000 in immediate cash expense, even before any changes to brokerage or inventory financing. Test a range of possible dates and rates rather than one optimistic scenario.

Document assumptions in a purchase order and communicate who bears changes in import duty under the agreed Incoterm. A DDP seller may need additional contingency pricing, while a DAP buyer often faces a separate clearance payment. Use the DDP vs DAP calculator to compare seller pricing under your verified duty assumptions.

Frequently asked questions

Are Section 301 and Section 232 tariffs always cumulative?

No. The current legal measures and any non-stacking or exclusion provisions must be checked for the actual product and entry date.

What is an HTSUS code?

It is a US tariff classification code used to identify imported goods for duty and statistical purposes. The national schedule extends beyond the international six-digit HS level.

Does a shipment country determine origin automatically?

No. Customs origin rules can depend on where goods were made or sufficiently transformed, not simply the last port or reseller.

Can this calculator produce a customs declaration?

No. It is only a cost scenario. The importer or licensed broker must use accurate classification, entry procedures and documentation.

What if a tariff exclusion expires?

A rate valid before expiration may be wrong for later entries. Always confirm effective dates and any transition terms before purchasing or importing.

Sources and related calculators

Important limitations

These figures are estimates and do not represent a government tariff determination or a binding freight quotation. See our calculation methodology and disclaimer.