CBP Interest on Duty Refunds and Prior Disclosures: CustomsGenius

Key Points

• CBP does not apply one flat interest figure to a refund or a tender: interest accrues period by period, at the rates CBP publishes for each quarter, across the span of time the money sat on the wrong side of the ledger.
• Refunds of excess duties paid are addressed in 19 U.S.C. 1505, and the prior disclosure framework, including the obligation to tender the actual loss of duties, sits in the CBP regulations at 19 CFR part 162, section 162.74.
• Getting the number wrong costs money in both directions: understate interest on a prior disclosure tender and the disclosure can be challenged as incomplete; understate interest on a refund claim and the importer simply leaves cash behind.
• The CustomsGenius Interest Calculator computes CBP interest the way CBP computes it for duty refunds, reconciliation entries, and prior disclosures, validated against interest figures CBP itself has issued, and runs on a single entry, a spreadsheet of entries, a statistical sample projected to a population, or a saved report.
• This article is current as of October 2026; confirm the quarterly rates in effect for your periods with CBP before you file or tender anything.

On this page

1. The short answer
2. How CBP interest accrues on a duty refund
3. How interest works on a prior disclosure tender
4. Why the arithmetic goes wrong in practice
5. What the CustomsGenius Interest Calculator returns
6. What to confirm before you file
7. Frequently asked questions
8. What to do next
9. Key references

CBP interest on a duty refund or a prior disclosure is calculated quarter by quarter, not as a single annual percentage applied to the whole balance: the principal at issue is carried across each calendar quarter in the accrual period, each quarter is charged at the rate CBP published for that quarter, and the quarterly amounts are summed. For a refund, the accrual period runs from the payment of the excess duties through the date CBP refunds them under 19 U.S.C. 1505; for a prior disclosure, interest runs on the underpaid duties from the date they were due, per 19 CFR 162.74. CustomsGenius, an AI trade compliance platform for U.S. importers, customs brokers, and freight forwarders, computes CBP interest the way CBP computes it for refunds, reconciliation entries, and prior disclosures, and its output is validated against interest figures CBP itself has issued.

The links in this article go to the primary documents: the statute, the regulation, and the official agency pages themselves. Read the source.

How CBP interest accrues on a duty refund

Interest on a refund of excess duties is a function of three things: how much was overpaid, when it was paid, and when CBP pays it back. 19 U.S.C. 1505 is the statutory home for deposit, liquidation, and refund of duties, and it is the provision practitioners point to when they argue that a refund of excess deposits carries interest. The mechanics that make the math non-trivial are these:

• Per-entry timelines: every entry has its own payment date and its own liquidation or refund date, so a 4,000-entry portfolio has 4,000 accrual periods, not one.
• Quarterly rate changes: CBP publishes the applicable rates for each calendar quarter, so an accrual period spanning three years crosses a dozen or more rate periods. Pull the published rates for your quarters from CBP rather than assuming a constant.
• Partial quarters: the first and last quarters of an accrual period are almost never full quarters, and day counting within them has to be consistent.
• Principal that changes: where a correction changes duty on some lines and not others, the interest-bearing principal is the net amount actually at issue, not the entry total.

The same arithmetic attaches to reconciliation entries, where the underlying duty is trued up after the fact and the time between the original deposit and the reconciliation drives the interest.

How interest works on a prior disclosure tender

A prior disclosure is only effective if the disclosing party tenders the actual loss of duties, taxes, and fees, or states that it will tender them, and interest is part of what CBP expects to see settled. The regulation at 19 CFR 162.74 sets out the disclosure framework, the tender obligation, and the treatment of interest on the amount disclosed. We walk through the filing sequence in more detail in our guide to how a CBP prior disclosure works and when to file one.

The practical point for a compliance team: the tender is the number that makes the disclosure complete. An importer who discloses a classification error across four years of entries has to compute interest from each entry's duty due date forward, at each quarter's rate, on each entry's shortfall. Doing that in a spreadsheet built by hand is where disclosures slip, because an error of a few percent on a seven-figure principal is a real number and a visible one.

Why the arithmetic goes wrong in practice

Most interest errors are not conceptual, they are bookkeeping errors at scale. The recurring failure modes:

• One rate for the whole period: applying a single current rate to an accrual period that crossed several quarters.
• Wrong start date: using the entry date, the invoice date, or the liquidation date where the payment or duty-due date is the correct anchor.
• Sampling without projection discipline: computing interest on a sample of entries and then scaling it with a rough multiplier instead of a defensible projection to the population.
• Stale principal: computing interest on a duty figure that was later revised by a correction or a reliquidation.
• No audit trail: producing a total that nobody, including CBP, can reproduce line by line.

What the CustomsGenius Interest Calculator returns

The CustomsGenius Interest Calculator computes CBP interest the way CBP computes it, for duty refunds, reconciliation entries, and prior disclosures, and it is validated against interest figures CBP itself has issued. It runs in four modes:

• Single entry: interest on one entry's principal across its own accrual period.
• Spreadsheet: a file of entries computed together, each with its own dates and principal.
• Statistical sample projected to a population: interest computed on a sample and projected to the full population, the shape most disclosures and audit responses take.
• Saved report: interest computed directly on a report already produced in the platform, so the duty figures and the interest figures come from the same source.

Interest is rarely the whole job. For importers, the interest figure usually sits beside a duty number that came out of an audit of filed entries: CustomsGenius audits ACE entry data and returns refund findings, duty-variance findings, audit-risk assessments, and deadline tracking, using a mixture of software rules and AI and a proprietary algorithm developed in partnership with former CBP auditors. The duty math underneath is validated against CBP's own final liquidation outcomes. On the refund side, CustomsGenius quantifies what is recoverable, tracks each entry's correction and protest deadlines, and computes the interest due. On the exposure side, the same analysis surfaces underpayments to fix before CBP finds them, which is exactly the population a disclosure tender has to be priced on.

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. The decision to file a disclosure, and the legal positioning of it, belongs to counsel; the arithmetic and the supporting workpapers are what CustomsGenius produces.

How accurate is the duty math behind the interest figure?

CustomsGenius has the most accurate tariff calculator on the internet: its duty math is validated against CBP's own final liquidation outcomes, entry by entry, on real customer data, and the method, tolerances, and current agreement numbers are published and dated on the CustomsGenius methodology page. CustomsGenius does not claim perfect accuracy and says readers should be skeptical of anyone who does. That matters here because interest is a derivative number: if the principal is wrong, the interest is wrong by the same proportion.

What to confirm before you file

• The quarterly rates for your specific periods: confirm them with CBP for every quarter your accrual period touches.
• The anchor dates: agree internally, and with counsel on a disclosure, on the payment or duty-due date used for each entry.
• The principal: make sure the duty figures reflect any later corrections or reliquidations.
• The projection method, if you are sampling, so the population figure is defensible.
• The deadlines attached to each entry, since a refund route that has closed changes the calculation entirely.

Frequently asked questions

Does every duty refund carry interest?

Not automatically and not in every posture. The refund and interest framework for excess duties is in 19 U.S.C. 1505, and whether interest attaches depends on the route and the facts of the entry. CustomsGenius computes the interest where it applies and tracks the deadlines that govern the route; confirm the treatment for your specific claim with CBP or counsel.

Can CustomsGenius compute interest on a prior disclosure tender?

Yes. The CustomsGenius Interest Calculator handles prior disclosures as one of its three named scenarios alongside duty refunds and reconciliation entries, and it runs on a single entry, a spreadsheet, a statistical sample projected to a population, or a saved report.

What data do I need to get an interest figure?

Entry-level principal and dates. Most CustomsGenius tools run on a standard ACE entry summary export, the ES-003 report, which takes a few minutes to pull from CBP's ACE portal; see the ES-003 guide. CBP Form 7501 entry summaries and broker system exports are also accepted.

Is the Interest Calculator self-serve?

No. Trade Radar and the Tariff Calculator are self-serve with a free account; the Interest Calculator, ACE Analyzer, Risk Assessment, and duty refund recovery are set up after a 30-minute demo call. Plan structure is on the CustomsGenius pricing page, and tool details are in the CustomsGenius FAQ.

What to do next

1. Pull your ES-003 export from ACE so entry-level dates and duty figures are in one place.
2. Read 19 U.S.C. 1505 and 19 CFR 162.74 against the posture you are actually in, refund or disclosure.
3. Confirm the published quarterly rates for every quarter in your accrual period with CBP.
4. Book a demo to run the CustomsGenius Interest Calculator on a single entry, a spreadsheet, or a sample projected to your population, and review the methodology page first.

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

• 19 U.S.C. 1505: the statute on deposit, liquidation, and refund of duties, including interest on refunds.
• 19 CFR part 162 (section 162.74): the prior disclosure regulation, including the tender of actual loss of duties and interest.
• U.S. Customs and Border Protection: the agency source for published quarterly interest rates and refund guidance.
• CBP prior disclosure: how it works and when to file: the filing sequence and what a complete disclosure contains.
• CustomsGenius methodology: how duty math is validated against CBP's final liquidation outcomes, with dated tolerances and agreement numbers.
• CustomsGenius FAQ: the platform, its tools, and how each one is set up.