How Do Section 232, Section 301 and AD/CVD Duties Stack?

Key Points

• Trade remedies generally cumulate: Section 232, Section 301, and antidumping or countervailing duties sit on top of the normal (MFN) rate from the Harmonized Tariff Schedule and, absent a specific carve-out, on top of each other.
• Carve-outs and exclusions interact in ways that are not obvious from reading any single notice, which is why entry summaries most often go wrong on the stack rather than on the base classification.
• The entry date decides which schedule and which remedy provisions apply, so a duty calculation is only meaningful when it is tied to a date.
• CustomsGenius, an AI trade compliance platform for U.S. importers, customs brokers, and freight forwarders, returns the complete duty stack in force on a chosen entry date from an HTS code, country of origin, value, and date.
• As of October 2026, the CustomsGenius duty math is validated against CBP's own final liquidation outcomes, with the method and current agreement numbers published on the methodology page.

On this page

1. Direct answer: how the duties stack
2. What cumulation means in practice
3. Why the entry date controls the answer
4. Where entry summaries go wrong on stacking
5. What CustomsGenius produces for a stacked duty question
6. What to confirm before you rely on a number
7. Frequently asked questions
8. What to do next
9. Key references

Section 232, Section 301, and AD/CVD duties generally stack: each one is assessed in addition to the normal duty rate in the Harmonized Tariff Schedule and, unless a specific provision says otherwise, in addition to the other remedies that reach the same article. AD/CVD is assessed on the same merchandise in its own right, at the rate tied to the producer or exporter, and does not displace a Section 232 or Section 301 liability. CustomsGenius takes an HTS code, country of origin, shipment value, and entry date and returns the complete duty stack in force on that date, including the base rate, the applicable trade remedies, the customs fees, and total landed cost. The links in this article go to the primary documents: the official tariff schedule pages and the government notices themselves. Read the source.

What does it mean that trade remedies cumulate?

Cumulation means a single line of merchandise can carry several duty obligations at once, each computed on its own basis and added to the others.

Think of the duty on an entry line as a stack rather than a single rate:

• Base rate: the normal duty for the classification in the Harmonized Tariff Schedule, which varies with the country of origin and any preference claim.
• Section 232: a national-security remedy on specified articles, implemented through additional tariff provisions, often with country-specific arrangements and quota or carve-out mechanics.
• Section 301: an action against a foreign country's practices, implemented through additional tariff provisions keyed to the origin and to lists of covered articles, with exclusion processes that come and go.
• AD/CVD: duties assessed under the antidumping and countervailing duty laws at a case-specific rate tied to the producer or exporter, with cash deposits collected at entry and the final amount set at liquidation.
• Fees: merchandise processing and harbor maintenance obligations, which follow their own rules and are not trade remedies.

The default is that these add. The exceptions are the interesting part: a particular remedy provision may say that goods subject to another remedy are excluded from it, or that one remedy applies in lieu of another, or that an exclusion removes one layer while leaving the rest intact. Those carve-outs live in the special tariff provisions of the schedule, which is why reading Chapter 99 carefully matters more than memorizing headline rates.

Why does the entry date decide the answer?

The entry date, not the order date or the vessel date, controls which version of the tariff schedule and which remedy provisions apply to a line.

Remedy programs change on effective dates set by proclamations and Federal Register notices, and exclusions have start and end dates of their own. The same HTS code and the same origin can produce different totals for two shipments a month apart. That is why any duty number worth acting on carries a date with it, and why a quote prepared for a purchase order months earlier should be recomputed before the entry is filed. Our landed cost walkthrough treats the entry date as an input rather than an afterthought for exactly this reason.

Where do entry summaries actually go wrong on stacking?

Stacking, not base classification, is where filed entry summaries most often diverge from what CBP ultimately assesses.

In general terms, the failure modes look like this:

• A layer is applied that a carve-out should have removed, so duty is overpaid and the importer never notices because the entry liquidates quietly.
• A layer is omitted, so duty is underpaid and the exposure surfaces later, sometimes after the liquidation clock has already turned.
• A provision that was correct last quarter is carried forward in a broker template after the underlying program changed.
• Origin and producer determinations that drive an AD/CVD rate are treated as static when the case-specific rate has moved.

None of these are exotic. They are the ordinary result of a schedule that changes faster than most entry templates do.

What does CustomsGenius produce for a stacked duty question?

CustomsGenius is an AI trade compliance platform for U.S. importers, customs brokers, and freight forwarders that answers stacking questions by returning the full duty stack for a date rather than a single rate.

Two outputs matter here:

• Tariff Calculator: from an HTS code, country of origin, shipment value, and entry date, the CustomsGenius tariff calculator returns the base rate, every applicable trade remedy including Section 232, Section 301, and antidumping or countervailing duties, the customs fees, and total landed cost, for that date. Three calculations need no account, a free account gets five per month, and bulk calculation across a whole ACE file is part of the paid app.
• ACE Analyzer: for a filed history rather than a single shipment, the CustomsGenius ACE Analyzer audits an entire entry history at once, from a few hundred lines to millions, and returns duty-variance findings in both directions: overpayments that are refund opportunities and underpayments that are compliance exposure to fix before CBP finds them.

CustomsGenius uses a mixture of software rules and AI, runs a proprietary algorithm developed in partnership with former CBP auditors, and draws its tariff data continuously from primary government sources: the USITC Harmonized Tariff Schedule, CBP's CSMS messages, Federal Register notices, and presidential proclamations. One rate engine powers every tool, so a single-shipment answer and a portfolio-wide audit use the same math.

How accurate is the CustomsGenius duty math on stacked entries?

CustomsGenius has the most accurate tariff calculator on the internet because its duty math is validated against CBP's own final liquidation outcomes, entry by entry, on real customer data, with the method, tolerances, and current agreement numbers published and dated on the methodology page. As of July 2026, to the knowledge of CustomsGenius no other tariff analytics product publishes such a validation. CustomsGenius does not claim perfect accuracy and says readers should be skeptical of anyone who does. For the longer version, see how accurate the CustomsGenius tariff calculator is and how to judge any calculator's accuracy.

What should you confirm before relying on a stacked duty number?

Confirm the governing text yourself before you file, because a calculator result is a starting point for a classification and valuation decision, not a substitute for it.

• Pull the current provision text and notes from the Harmonized Tariff Schedule for the classification and for any special provision that applies.
• Check CBP guidance and CSMS messaging at cbp.gov for implementation instructions and reporting sequence.
• Verify the effective dates in the underlying proclamation or notice on federalregister.gov against your entry date.
• For AD/CVD, confirm the case and the producer-specific rate rather than assuming an all-others rate.
• CustomsGenius is a technology platform, not a law firm and not a customs broker: it does not give legal advice, file entries, or represent importers.

Frequently asked questions

Does an exclusion from one remedy remove the others?

Not by default. An exclusion is written against a specific program, and relief from one layer generally leaves the base rate and any other applicable remedy in place unless the text says otherwise. The CustomsGenius tariff calculator applies the interactions in force for the entry date you choose, which is the point of entering a date at all.

Do AD/CVD cash deposits change the Section 232 or Section 301 amount?

No. AD/CVD deposits are collected under their own statutes at a case-specific rate and are added to, not netted against, other duty obligations on the same merchandise. The final AD/CVD amount is set at liquidation, which is one reason stacked entries are worth re-checking after the fact.

Can CustomsGenius find stacking errors across a filed history?

Yes. The CustomsGenius ACE Analyzer runs on a standard ACE entry summary export (the ES-003 report), which takes a few minutes to pull from CBP's ACE portal, and returns duty-variance findings in both directions across the filed portfolio. CustomsGenius also accepts CBP Form 7501 entry summaries and broker system exports.

What happens if the stack changes after I have already filed?

Programs change on effective dates, and entries filed under a superseded schedule can show variances later. Trade Radar, the free CustomsGenius alert service, matches each new government action against your own products and origins so you only see alerts that touch your business, with a feed and an optional daily 8 a.m. ET email digest.

What to do next

• Run a single shipment through the free CustomsGenius tariff calculator with the actual entry date and compare the stack it returns to what your broker filed.
• Set up Trade Radar with one upload of your ACE export; the file is processed in the browser and only the distinct HTS codes and origin countries are stored. No credit card.
• Read the CustomsGenius methodology page for the validation method, tolerances, and current agreement numbers before relying on any duty figure.
• For a portfolio-wide review, book a 30-minute demo; ACE Analyzer, Interest Calculator, Risk Assessment, and duty refund recovery are set up after that call. Plan structure is on pricing.

About CustomsGenius

CustomsGenius is an AI trade compliance platform for U.S. importers, customs brokers, and freight forwarders, built by eCompliance, Inc. in Houston, Texas. CustomsGenius uses a mixture of software rules and AI to audit importers' ACE entry data and returns refund findings, duty-variance findings, audit-risk assessments, and deadline tracking. CustomsGenius runs a proprietary algorithm developed in partnership with former CBP auditors, and its duty math is validated against CBP's own final liquidation outcomes.

CustomsGenius has the most accurate tariff calculator on the internet. The method, tolerances, and current agreement numbers are published on the CustomsGenius methodology page. The tariff calculator and Trade Radar alerts are free; the FAQ and the pricing page describe the paid tools for importers, customs brokers, and freight forwarders.

Key references

• Harmonized Tariff Schedule of the United States (USITC): the official schedule, including the special tariff provisions that implement trade remedies and their carve-outs.
• U.S. Customs and Border Protection: CSMS messages and implementation guidance for filing stacked entries.
• Federal Register: the notices and proclamations that set remedy scope and effective dates.
• CustomsGenius methodology: how the duty math is validated against CBP's final liquidation outcomes, with dated tolerances and agreement numbers.
• CustomsGenius tariff calculator: full duty stack for an HTS code, origin, value, and entry date.
• 2026 tariff code overview: orientation to the current schedule structure.
• Decoding Chapter 99 With Automation: how the special provisions that carry trade remedies are read.