Entry Number Format: How the 11-Character CBP Entry Number Works

Key Points

• The CBP entry number is 11 characters in the format FFFNNNNNNNN, entered without hyphens: a three-character filer code, a seven-digit sequence number, and one check digit.
• The filer assigns the entry number in ABI when creating the entry, before or at cargo release, and it must be unique for that filer.
• The check digit is computed on the preceding 10 characters using the published formula in the CATAIR ACE ABI Entry Summary Create/Update chapter (September 2025), AE Table 1, and a failed check digit fails validation.
• The entry number is reported in Block 1 of CBP Form 7501 (02/26) and keys the entry through summary, statement, liquidation, protest, refund and audit.
• A mistyped entry number on a protest or refund request points CBP at the wrong entry, so it is not the place to rely on memory or retyping.

On this page

1. At a glance
2. What is the entry number format made of?
3. When is the entry number assigned, and who is responsible?
4. How is the entry number format validated in ACE?
5. Common entry number format errors and what they cost
6. How the entry number differs from other identifiers on the entry
7. Frequently asked questions
8. What importers and brokers should do
9. Key references

The entry number format is the fixed 11-character structure of the CBP entry number: a three-character filer code assigned by CBP, a seven-digit filer-assigned sequence number, and one check digit, written FFFNNNNNNNN without hyphens. Customs brokers and self-filing importers assign the entry number in ABI when they create the entry, and it is reported in Block 1 of CBP Form 7501 (02/26). From release through liquidation, protest and refund, the entry number is the key CBP uses to find the entry.

This reference reflects the entry number format as of November 2026. The links in this article go to the primary documents: the CBP forms, the ACE CATAIR, and the official regulation and tariff schedule pages themselves. Read the source.

At a glance

• Full name: CBP entry number (11-character entry number format)
• Who prepares or uses it: The filer (licensed customs broker or self-filing importer) assigns it; CBP, sureties and auditors use it to identify the entry
• When in the lifecycle: Assigned at entry creation, before or at cargo release; used through summary, statement, liquidation, protest, refund and audit
• System or channel: ABI transmissions to ACE; Block 1 of CBP Form 7501 (02/26)
• Format: FFFNNNNNNNN, no hyphens
• Governing authority: CBP; check digit per CATAIR ACE ABI Entry Summary Create/Update (September 2025), AE Table 1
• Related terms: IOR number, ultimate consignee number, filer code, entry type 01, entry type 03, entry type 06

What is the entry number format made of?

The entry number format has three fixed parts that always appear in the same order and together total 11 characters.

Filer code (three characters)

The first three characters are the filer code assigned by CBP to the broker or self-filer. The filer code identifies who filed the entry, not who owns the goods. Every entry number a given filer creates starts with that filer's code.

Sequence number (seven digits)

The next seven characters are the filer-assigned sequence number, and they are all numeric. The filer controls this sequence and must never reuse a number, because the full entry number has to be unique for that filer.

Check digit (one character)

The final character is a check digit computed on the preceding 10 characters. CBP publishes the formula in the CATAIR ACE ABI Entry Summary Create/Update chapter (September 2025), AE Table 1. Filing software normally computes it automatically; confirm your system's implementation against the current CATAIR rather than calculating by hand.

When is the entry number assigned, and who is responsible?

The entry number is assigned by the filer when the entry is created in ABI, before or at cargo release. The broker or self-filing importer is responsible for choosing an unused sequence number, attaching the correct filer code, and making sure the check digit computes.

Once assigned, the entry number does not change as the entry moves forward. It ties the release record to the entry summary, places the entry on a statement, and identifies the entry at liquidation. Later, a protest, a refund request, a post-entry correction or an audit request will cite that same entry number. For refund work, an ACE report that lists entry numbers is usually the starting point; see the ES-003 Guide: How to Retrieve Your ACE Report for IEEPA Tariff Refunds.

The entry number format is the same regardless of entry type. An entry type 01 (ACE entry summary type code 01, Consumption, Free and Dutiable), an entry type 03 (Consumption, AD/CVD, carrying the case number and deposit), and an entry type 06 (Foreign Trade Zone consumption entry withdrawing zone merchandise, including weekly estimated entries) all use the same 11-character structure. The entry type is a separate data element, not something encoded in the entry number.

How is the entry number format validated in ACE?

The entry number format is validated by ACE when the filer transmits the entry through ABI. Two conditions must hold: the entry number must be unique for that filer, and the check digit must compute under the CATAIR formula. If either fails, the transmission fails validation and the filer must correct and retransmit.

Format also matters: the number is transmitted as 11 characters, FFFNNNNNNNN, with no hyphens. Confirm current record layouts and error responses in the ACE CATAIR, since CBP updates chapters over time.

Common entry number format errors and what they cost

Entry number format errors fall into a few predictable patterns, and the most expensive ones happen long after release.

• Reused sequence number: Assigning a sequence number already used by the same filer breaks uniqueness, and the transmission fails validation.
• Bad check digit: A manually keyed or miscomputed check digit fails validation.
• Hyphens or wrong length: Adding hyphens or dropping a digit breaks the 11-character format.
• Transposed digits on a protest or refund request: This is the costly one. ACE may accept a valid-looking number that belongs to a different entry, pointing CBP at the wrong entry and delaying or derailing the claim.
• Confusing identifiers: Entering an in-bond number, bill of lading number, importer number or filer code alone where the entry number belongs.

How the entry number differs from other identifiers on the entry

The entry number identifies one entry; most other numbers on the entry identify a party, place or carrier. Keeping them distinct prevents the most common mix-ups.

• IOR number: The importer of record number (IRS EIN, optionally suffixed, SSN, or CBP-assigned number) identifies the party liable for duties. It is not part of the entry number.
• CBP-assigned number: The importer identification number CBP issues via CBP Form 5106 to a party lacking an EIN or SSN, in format YYDDPP-NNNNN. It identifies an importer, not an entry.
• Ultimate consignee number: The EIN, SSN or CBP-assigned number of the party on whose account goods are shipped, reported with the importer number.
• Filer code: Only the first three characters of the entry number; on its own it identifies the filer, not the entry.
• FIRMS code: The Facilities Information and Resources Management System code, a four-character identifier of the bonded facility, pier, CES or warehouse holding the cargo.
• SCAC code: The Standard Carrier Alpha Code, a two-to-four-letter carrier identifier issued by the National Motor Freight Traffic Association.
• Schedule D port codes: Census Schedule D four-digit district and port codes, such as port code 5301 for the Houston, TX seaport, reported as port of entry or unlading.

For other line-level identifiers, see MID Code: Manufacturer Identification Code Explained for Brokers.

Frequently asked questions

How many characters are in the entry number format?

The entry number format is 11 characters: a three-character filer code, a seven-digit filer-assigned sequence number, and one check digit, written FFFNNNNNNNN with no hyphens.

Who assigns the entry number?

The filer assigns the entry number in ABI when creating the entry, before or at cargo release. CBP assigns the filer code that forms the first three characters, but the sequence number is the filer's responsibility.

Where does the entry number appear on CBP Form 7501?

The entry number is reported in Block 1 of CBP Form 7501 (02/26), and the same entry number identifies the entry in ACE.

Is the entry number format different for FTZ or AD/CVD entries?

No. The entry number format is identical for entry type 01, entry type 03 and entry type 06; the entry type is reported separately.

What importers and brokers should do

• Let ABI software generate sequence numbers and check digits, and confirm the logic against CATAIR AE Table 1 after each CATAIR update.
• Copy entry numbers for protests, refund requests and corrections directly from ACE reports rather than retyping them.
• Train staff to distinguish the entry number from the in-bond number, bill of lading number, IOR number and filer code.
• Keep a filer-level log of assigned sequence numbers so no number is ever reused.

Key references

• CBP forms library: source for CBP Form 7501 (02/26), where Block 1 holds the entry number, and CBP Form 5106.
• ACE CATAIR: includes the ACE ABI Entry Summary Create/Update chapter (September 2025), whose AE Table 1 publishes the check-digit formula.
• Electronic Code of Federal Regulations: current text of the customs regulations governing entry.
• Harmonized Tariff Schedule of the United States: official tariff schedule used in the entry lines keyed to each entry number.