Understanding the system behind container identity: what the BIC prefix really means
Every shipping container has its own internationally recognized ID – a combination of letters and numbers that makes it traceable from port to port, across borders, and through complex supply chains. At the core of this ID is the container prefix, a four-letter code that identifies the registered owner or principal operator of the container.
These prefixes are issued by the Bureau International des Containers (BIC), the Paris-based organization responsible for overseeing global standardization of container identification under ISO 6346. The BIC ensures that every registered prefix remains unique and verifiable in customs systems, tracking platforms, and documentation across the freight sector.
It’s worth clarifying that this BIC prefix has nothing to do with banking. Despite sharing the acronym, it is entirely unrelated to the Bank Identifier Code used in financial transactions. In container logistics, a BIC code refers specifically to a globally accepted system for identifying intermodal containers – not bank accounts.
In this guide, you’ll get a detailed look into how container prefixes are structured, who issues them, how they are verified, and why they remain a foundational element in ensuring traceability, legal compliance, and operational efficiency in international transport.
What is a container prefix?
A container prefix is a four-letter code that appears at the start of every standardized shipping container number. It serves one key function: to identify the owner or main operator of the container across global transport systems. This code is assigned according to the ISO 6346 standard and issued through the Bureau International des Containers (BIC).
Take the number MAEU1234567. The prefix MAEU indicates ownership by Maersk Line, one of the largest global container carriers. The prefix is followed by a six-digit serial number (123456) and a single check digit (7), forming a unique identifier used throughout shipping documents, tracking systems, and customs databases.
Each registered prefix allows up to 1,000,000 serial combinations, giving owners flexibility to label extensive fleets. Because container numbers must remain globally unambiguous, the BIC enforces strict naming protocols to avoid duplication and ensure clarity during container handling, digital tracking, and regulatory inspections.
Prefix registration isn’t optional or cosmetic – it’s a technical requirement for intermodal containers to move legally and efficiently in international trade.
Who is BIC and what is their role?
The Bureau International des Containers (BIC) is the official authority responsible for assigning container owner codes across the global shipping sector. Established in 1933 and headquartered in Paris, the BIC was created to promote standardization in intermodal transport. Today, it manages the BIC Code Register, the definitive database of container prefixes governed by the international standard ISO 6346.
The BIC operates in close cooperation with regional partners called National Registration Organizations (NROs). In the German-speaking countries, the SGKV (Studiengesellschaft für den Kombinierten Verkehr) handles registration support, provides guidance, and mediates issues on behalf of users in Germany and Austria.
This global framework ensures that every registered prefix remains unique, traceable, and legally valid. Customs authorities, port operators, shipping lines, and freight forwarders rely on the BIC’s register to confirm container ownership, validate documentation, and prevent fraudulent use. Without this structure, container tracking and regulatory control across borders would break down.
How container numbers are structured
Every shipping container registered under ISO 6346 carries a unique identifier composed of four letters, six numbers, and one check digit. This system creates a standardized and globally recognizable code that ensures consistency across customs systems, transport networks, and digital tracking platforms.
A container number consists of three components:
- Prefix (4 letters): The first three letters indicate the owner or operator, while the fourth letter specifies the equipment category:
- U – Standard freight container
- J – Detachable container-related equipment
- Z – Trailers or chassis
- U – Standard freight container
- Serial number (6 digits): This number is assigned by the container owner and uniquely identifies the container within their fleet. For example, in HLBU1509039, the six-digit serial number is 150903.
- Check digit (1 digit): The final number, here 9, is calculated using a predefined algorithm. It verifies the integrity of the full container number and helps systems detect data-entry errors. On the container, this digit is typically displayed in a box, making it easy to identify.
A number like HLBU1509039 clearly illustrates the structure: HLBU identifies the owner and equipment type, 150903 is the unique registration number, and 9 is the mathematically derived check digit that validates the sequence.
This structure is not a recommendation – it’s a formal requirement under ISO 6346. The standard also specifies how and where the number must appear: on both side panels and the container door, using a standard font size and layout to ensure visibility during crane operations, inspections, and port handling.
Understanding the BIC code register
The BIC Code Register is the official global database of all registered container prefixes. Maintained by the Bureau International des Containers (BIC), the register ensures that every container operating in international trade carries a globally unique identification code. It’s a key reference for customs authorities, shipping lines, terminal operators, and freight forwarders who need to confirm ownership and prevent misuse.
There are three primary types of container codes listed in the register:
- Owner codes – Assigned to the company that legally owns the container, typically a shipping line or leasing firm.
- Operating codes – Used when a company other than the owner is responsible for operating or managing the container.
- Leasing codes – Assigned to firms that lease containers under contractual agreements, often across multiple operators.
Each code ends with a mandatory category identifier that defines the equipment type:
- U – Freight containers
- J – Detachable container-related equipment
- Z – Trailers and chassis
For example, TEXTU designates a specific freight container owned or operated by a registered company. The prefix must appear on the container exactly as issued. Any alteration – even a missing or changed letter – can trigger customs delays or cause tracking systems to reject the number.
Companies applying for a prefix through BIC must pay a one-time fee of €2,000, which includes certification. An annual renewal is required to keep the code active, currently set at €475 per year, and BIC also offers an optional membership for €46 per year. These fees fund the ongoing maintenance of the register and support BIC’s role in global standardization.
The register is publicly accessible through bic-code.org and updated regularly. This ensures container numbers remain reliable, verifiable, and fully compliant with international requirements under ISO 6346.
How to verify a container prefix and number
Every ISO 6346 container number includes a final digit known as the check digit – a single number that confirms the accuracy of the container’s prefix and serial number. This digit isn’t arbitrary. It’s calculated using a standard method called the Modulo 11 algorithm, which makes it possible to detect entry errors or inconsistencies before a container is processed.
Here’s how the check digit is calculated:
- Assign numeric values to each letter in the prefix, using a predefined conversion table. For example, A = 10, B = 12, C = 13, and so on.
- Multiply each character (letters and numbers) by a fixed weighting factor based on its position in the container number.
- Add the results and divide the total by 11.
- The remainder becomes the check digit. If the remainder is 10, the digit is set to 0 by default.
This digit typically appears inside a box to set it apart from the rest of the number. Terminals, carriers, port authorities, and customs systems rely on this verification step to reject incorrect or suspicious entries before containers move further in the logistics chain.
The BIC provides a free online calculator to validate any container number. Simply enter the four-letter prefix and the six-digit serial number, and the tool will generate the correct check digit. If the result doesn’t match the container’s printed number, it could point to a data entry error, a forgery, or a registration issue – any of which may delay clearance or trigger further inspection.
For global operators and freight forwarders, validating the check digit should be a standard step before entering a container into any booking or tracking system.
Why container prefixes matter in global shipping
Container prefixes may look like minor markings, but in a sector that moves over 80% of global cargo by sea, these four letters are essential to the integrity of international trade. Prefixes anchor the identity of every container and connect it to ownership, operational control, and legal accountability.
Tracking and traceability
Prefixes make global tracking possible. With millions of containers in motion at any given time, supply chain systems depend on prefixes to identify who owns a container, who operates it, and where it is in the network. Whether it’s a port terminal in Rotterdam or a freight hub in Singapore, accurate prefixes ensure containers move through systems without confusion.
Customs and compliance
Customs authorities verify prefixes against the BIC Code Register to confirm legal ownership. An unregistered or incorrect prefix forces customs officials to conduct a full inspection, which increases turnaround times and may lead to storage fees, penalties, or shipment holds. For time-sensitive cargo, this kind of disruption affects the entire chain.
Fraud prevention
Prefixes serve as a built-in safeguard against container fraud. Because the BIC strictly regulates prefix issuance, the presence of a valid prefix on a container links it to a verified owner. This helps prevent the unauthorized duplication, counterfeiting, or leasing of containers under false credentials.
Insurance and liability
In the event of damage, loss, or theft, the container prefix identifies the responsible party – often the owner, operator, or lessor. Insurers, freight forwarders, and legal teams use this information to process claims, assign liability, and resolve disputes. The prefix creates a traceable record that supports contract enforcement and compliance with international liability conventions.
In short, container prefixes aren’t just part of a numbering system. They protect the flow of goods, uphold commercial agreements, and enable a connected, accountable transport infrastructure.
Where to find container prefix information
Accurate container identification starts with reliable data. Whether you need to validate a prefix, confirm ownership, or calculate a check digit, several trusted sources provide up-to-date and authoritative information.
BIC Code Register
The BIC Code Register is the global source of truth for container prefix validation. Maintained by the Bureau International des Containers, it lists all active codes assigned under the ISO 6346 standard. Customs agencies, shipping lines, and digital platforms reference this database to ensure containers are correctly identified and legally compliant. You can access it directly at bic-code.org.
ISO 6346 documentation
For technical specifications – including number formatting, placement, character sizing, and verification methodology – refer to the official ISO 6346 standard. National standards bodies or ISO’s own platform make this documentation available, primarily for software developers, compliance teams, and engineers integrating the format into tracking and logistics systems.
Shipping line and leasing company directories
Major shipping lines and leasing companies often publish their registered prefixes on their websites. These pages serve as quick reference tools for customers, partners, and terminals that interact with containers owned or operated by these firms.
Online check digit calculators
Before a container number enters any booking or transport system, it should be verified. The BIC’s official check digit calculator allows you to input a prefix and serial number to validate the check digit instantly. This step helps eliminate typos and reduces the risk of processing delays or customs issues.
SGKV – national support in Germany and Austria
For companies based in Germany and Austria, the SGKV (Studiengesellschaft für den Kombinierten Verkehr) serves as the National Registration Organization (NRO). SGKV handles local registration support, answers technical questions, and provides mediation if issues arise during the application or use of BIC codes. They are the primary contact for all BIC-related inquiries in the German-speaking region.
Whether you’re a logistics manager in Antwerp, a freight coordinator in Hamburg, or a compliance officer in Singapore, these resources form the backbone of container identification – helping ensure traceability, legal clarity, and operational efficiency across international routes.
When to use a BIC code vs. an ILU code
Not every loading unit on Europe’s roads or rails requires a BIC code. While the BIC code remains the global benchmark for international container identification, certain transport scenarios within continental Europe call for a different solution: the ILU code.
Understanding the distinction between these two systems ensures that operators avoid compliance issues and streamline transport across different modes.
The basic rule: international = BIC, continental = ILU
Use a BIC code if the container:
- complies with ISO 6346 standards
- is designed for international transport
- will be used in intermodal shipping, including sea freight
- is likely to enter customs territory, reach a port, or shift between transport modes (e.g. road to rail or ship)
Use an ILU code (Intermodal Loading Unit) if the unit:
- is a non-ISO swap body, common in Europe
- operates strictly on road and rail within continental networks
- is not intended to be loaded onto ships
- remains within EU domestic transport corridors, particularly in Germany, Austria, or Benelux
The ILU code format mirrors the BIC structure, using four letters followed by digits and a check digit, but it’s managed by the International Union for Road-Rail Combined Transport (UIRR) rather than BIC. Critically, a loading unit may not display both a BIC and an ILU code at the same time – doing so violates both standards and creates confusion in automated systems.
Knowing when to register a BIC code
If a container is ever expected to leave the European mainland, pass through a seaport, or interact with customs systems, the BIC code is not optional – it’s required. Skipping this step can result in denied loading, manual inspections, or invalid tracking in global systems.
Units used purely for internal site logistics or short-range factory movements typically don’t need either code, provided they never enter public transport infrastructure.
By choosing the correct code at the outset, operators align with legal requirements and simplify the container’s journey across networks that depend on harmonized identifiers.
Container prefixes decoded: what every logistics pro should know
Behind every container on the move is a code that speaks volumes – about ownership, responsibility, and compliance. Container prefixes, issued by the Bureau International des Containers (BIC) and governed under ISO 6346, form the cornerstone of container identification worldwide.
These four-letter prefixes aren’t just administrative details. They are essential for accurate tracking, customs clearance, insurance claims, and real-time logistics visibility. A single incorrect or unregistered prefix can result in shipment delays, compliance flags, or even penalties at border crossings.
Mastering how container numbers are structured – and how to verify them using the BIC Code Register – gives logistics professionals the confidence to avoid costly mistakes and streamline operations across land and sea. Whether you’re moving units between Hamburg and Singapore or operating in local European corridors, understanding the role of container prefixes makes every shipment more secure, efficient, and compliant.
FAQ: BIC container prefixes
Container prefixes are more than just letters on a steel box. They’re legal identifiers, logistics tools, and key compliance markers in global trade. Below, we answer the top questions professionals ask about BIC codes, container prefixes, and how to stay compliant and efficient in global shipping.
How can I check if a container prefix is valid?
To check if a prefix is valid, use the BIC’s online Code Register or check digit calculator. These tools confirm ownership and ensure the number is correctly formatted and globally recognized under ISO 6346.
Who issues container prefixes?
Container prefixes are issued by the Bureau International des Containers (BIC) in Paris. The BIC maintains the official register under ISO 6346 and ensures each code is unique and verifiable across global logistics platforms.
What does the check digit mean in a container number?
The check digit is the final number in the container code. It validates the prefix and serial number using the Modulo 11 algorithm. If incorrect, it flags a possible entry error or issue with the container’s registration.
Can I use both a BIC code and an ILU code on the same container?
No, using both codes on a single container violates compliance rules. Choose BIC for international/intermodal use and ILU for EU inland transport. Each code serves a different purpose and must be applied exclusively.
How much does it cost to register a BIC container prefix?
Registering a prefix with BIC costs €2,000 upfront. An annual renewal fee of €475 is required to keep the code active. Optional BIC membership is available for €46 per year to support the system and receive updates.
Where can I find the most up-to-date container prefix data?
The official BIC Code Register at bic-code.org offers real-time data on all registered prefixes. It’s used by customs, ports, and logistics providers to verify container ownership and prevent delays.
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