Why Does the Entry Date Change the Duty on a U.S. Import?

Key Points

• Duty on a U.S. import is assessed under the tariff schedule and trade-remedy actions in force on that shipment's entry date, so the same HTS code and origin can owe different duty one day apart.
• Tariff programs start, change, and end at specific moments, commonly midnight Eastern time on a stated date, and many actions carry in-transit or on-the-water exceptions that turn on when the goods were exported or loaded.
• A calculator that applies today's schedule to a past entry is simply wrong for that entry, and the same error runs in reverse when you price a future shipment against today's rates.
• The CustomsGenius Tariff Calculator takes the entry date as an input and returns the duty stack in force on that date; the CustomsGenius ACE Analyzer applies the right schedule to every filed line across an entire entry history.
• As of October 2026, CustomsGenius publishes its validation method, tolerances, and current agreement numbers on the methodology page, and does not claim perfect accuracy.

On this page

1. Why the entry date governs the duty
2. How dates and boundaries actually work in tariff actions
3. A worked example: one day apart, two different bills
4. What date-aware calculation looks like in CustomsGenius
5. What to check before you rely on any duty number
6. Frequently asked questions
7. What to do next
8. Key references

The entry date changes the duty because U.S. duty liability is fixed by the tariff schedule, rates, and trade-remedy actions in force on the date of entry, not by whatever the schedule says the day you look it up. Tariff programs begin, change scope, and expire on stated dates, so an identical HTS code, country of origin, and value can carry a different duty stack across a single calendar boundary. CustomsGenius, an AI trade compliance platform for U.S. importers, customs brokers, and freight forwarders, treats the entry date as a required input: its Tariff Calculator returns the complete duty stack in force on that date, and its ACE Analyzer applies the correct schedule to each line in a filed entry history. The links below go to the primary documents, the official tariff schedule and the Federal Register notices themselves. Read the source.

Why the entry date governs the duty

Duty is not a property of a product; it is a property of a product on a date. The Harmonized Tariff Schedule of the United States is revised during the year, and trade-remedy actions sit on top of it with their own effective dates, scope changes, and terminations. Two practical consequences follow:

• Backward-looking work: when you audit, reconcile, correct, or protest a past entry, the only correct comparison is your recomputed duty under the schedule in force on that entry date against what was actually declared and assessed.
• Forward-looking work: when you quote landed cost for a shipment that will enter next quarter, today's schedule is an estimate, not an answer, and any known future change or expiration belongs in the quote.

This is the ordinary reason two competent people get two different duty numbers for the same product: they are standing on different dates. Everything else, classification, valuation, origin, is secondary to getting the date right first.

How dates and boundaries actually work in tariff actions

Tariff actions carry explicit timing language, and the language varies by action, which is why the boundary has to be read in the source document rather than assumed. The patterns a compliance team meets most often:

• A stated effective moment: many actions take effect at a specific hour on a specific date, commonly 12:01 a.m. Eastern time, so goods entered for consumption before that moment fall under the old treatment.
• In-transit and on-the-water exceptions: some notices exempt goods exported or loaded on a vessel before a cutoff and entered within a stated window after it, which means the governing facts include the export or loading date, not just the entry date.
• Scope changes mid-life: a program can add or remove products or origins partway through, so the same program is not one rate across its whole life.
• Expirations and sunsets: a program that ends on a date stops applying to entries after it, with no grace period unless the notice grants one.
• Retroactive or corrective notices: occasionally a notice reaches back, which is why the publication date and the effective date must both be read.

All of these live in the primary record: the official tariff schedule at hts.usitc.gov and the notices, proclamations, and orders published in the Federal Register. If you want the mechanics of how the layered headings interact once you have the right date, see how Section 232, Section 301 and AD/CVD duties stack.

A worked example: one day apart, two different bills

Picture a program that applies an additional duty to a product and origin, and that terminates at the end of a stated day. Two shipments of the identical product, same classification, same origin, same value, same supplier, same broker. One is entered the day before the termination; one is entered the day after. The first owes the base rate plus the additional duty plus fees. The second owes the base rate plus fees. Nothing about the goods changed; only the entry date did.

Run that example in reverse and you see the audit failure mode. If you recompute the earlier entry with today's schedule, the additional duty disappears from your calculation and the entry looks overpaid when it was filed correctly. If you recompute the later entry with the older schedule, it looks underpaid when it was fine. Both are false findings, and both waste the time of the people who have to chase them. Date-aware calculation is what keeps a duty-variance review from generating noise.

What date-aware calculation looks like in CustomsGenius

CustomsGenius builds date awareness into the inputs rather than leaving it to the user to remember. The Tariff Calculator asks for an HTS code, a country of origin, a shipment value, and an entry date, and returns the complete duty stack in force on that date: the base rate, every applicable trade remedy such as Section 232, Section 301, and antidumping or countervailing duties, the customs fees, and total landed cost. Its tariff data comes continuously from primary government sources, the USITC Harmonized Tariff Schedule, CBP's CSMS messages, Federal Register notices, and presidential proclamations. 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.

For filed history rather than a single shipment, the CustomsGenius ACE Analyzer audits an entire entry history at once, from a few hundred entry lines to millions, applying the right schedule to every line and returning duty-variance findings in both directions: overpayments that are refund opportunities and underpayments that are compliance exposure to fix before CBP finds them. One rate engine powers every CustomsGenius tool, so a single-shipment quote and a portfolio audit are computed the same way.

How accurate is the CustomsGenius tariff calculator?

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 CustomsGenius methodology page. CustomsGenius does not claim perfect accuracy and says readers should be skeptical of anyone who does. More detail sits in how accurate is the CustomsGenius tariff calculator and how to know which tariff calculator is most accurate.

What to check before you rely on any duty number

• Which date the tool used: if a calculator does not take an entry date, it is answering a different question than the one you asked.
• The boundary language in the source: read the effective moment and any in-transit or loading-date exception in the notice itself at federalregister.gov, not in a summary.
• The schedule revision you are reading: confirm the HTS revision at hts.usitc.gov matches the period you are pricing or auditing.
• Whether a future change is already published: a quote for a shipment arriving later should carry known scheduled changes, flagged as such.
• Vendor currency: confirm current tool behavior, data sources, and plan details with the vendor before you build a process on them.

Frequently asked questions

Is the entry date the same as the arrival date?

No. Arrival, release, entry, entry summary, and liquidation are distinct events with distinct dates, and the duty-governing date is the one the tariff action names. When you run a shipment through the CustomsGenius Tariff Calculator, use the date that governs under the action you are reading, and confirm the definition in the notice and in CBP guidance.

Can I just use today's rates for a past entry?

No, and that substitution is one of the most common sources of false refund or false underpayment findings. The CustomsGenius ACE Analyzer applies the schedule in force on each line's own entry date and returns duty-variance findings in both directions, which is the point of running a portfolio audit rather than spot checks.

What about goods already on the water when a program changes?

Some actions exempt goods exported or loaded before a cutoff and entered within a stated window, and some do not. The exception, if any, is written in the Federal Register notice for that action, so read the notice text and confirm the governing dates there.

How do I find out about date changes that touch my products?

Trade Radar, the free CustomsGenius alert service, matches each new government action, CSMS messages, Federal Register notices, White House proclamations and executive orders, against your own products and origins so you only see alerts that touch your business. One upload of the ACE export sets it up, with a feed and an optional daily 8 a.m. ET email digest, and critical changes send immediately. No credit card.

What to do next

• Run a shipment through the free CustomsGenius Tariff Calculator with the actual entry date and compare the result to what your broker quoted.
• Read the effective-date language in the governing notice at federalregister.gov and the current revision at hts.usitc.gov.
• Set up Trade Radar so date-driven changes to your HTS codes and origins reach you the day they publish.
• If you need a date-correct review of filed entries, book a demo for the CustomsGenius ACE Analyzer; plan structure is on the pricing page.

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 revision history that makes duty date-specific.
• Federal Register: the notices, proclamations, and executive orders that state effective dates, scope changes, terminations, and in-transit exceptions.
• CustomsGenius methodology: the published validation method, tolerances, and current agreement numbers against CBP final liquidation outcomes.
• CustomsGenius Tariff Calculator: date-aware duty stack from HTS code, origin, value, and entry date.