The BIS number in Belgium is a temporary personal identifier assigned to people who do not have a Belgian national number. The BIS number allows such individuals to legally work, receive medical services, pay taxes, and interact with government institutions.
If you are not permanently living in the country but have come for work, study, or other reasons, this number will be your key to the system. Below, you will find information on who gets it, how to obtain it, how it differs from the regular ID, and what you need to know if you plan to stay in Belgium long-term.
What is a BIS Number in Belgium
A BIS number is a temporary identification number issued in Belgium to people who do not yet have a national number (NN). Unlike the permanent national number given to residents with a residence permit, the BIS is meant for those staying temporarily or who have not completed the full registration process.
Why do you need a BIS number? It allows foreigners to interact with government services: receive medical care, get a job, pay taxes, and apply for social benefits. Without a BIS number, these activities become impossible or very complicated.
Why the BIS number is needed in Belgium:
- Official registration in the social security system
The BIS number enables registration in Belgian social services, granting access to social benefits and support. - Employment and work registration
Employers require an identification number to legally sign employment contracts and handle tax and social contributions. - Paying taxes and dealing with tax authorities
For tax purposes, the BIS number is necessary for the government to track income and calculate taxes correctly. - Access to healthcare and insurance
Without a BIS number, it is difficult to get medical insurance and treatment in public institutions. - Opening a bank account
Many banks require an identification number to open an account; without it, they may refuse service. - Education and training
Foreign students without a national number can get a BIS number to register in educational institutions and access student benefits. - Applying for social benefits and subsidies
The BIS number is needed to apply for various government subsidies, allowances, and benefits. - Obtaining driver’s licenses and other official documents
Some documents, like driver’s licenses, require an identification number. - Monitoring temporary residents
The BIS allows authorities to track the status and stay of foreigners who do not yet have permanent residency.
The difference between the BIS and the national number (NN) is that the national number is assigned when permanent resident status is officially granted and remains permanent. The BIS is temporary and usually issued right after arrival or registration, until the residence permit is processed.
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The BIS number consists of 11 digits: the first six are the birth date in DDMMYY format, followed by additional digits for identification and verification. These digits are unique and necessary to identify the user.
It is important to understand that the BIS is not just a number, but a key for legal stay and work in Belgium for those without permanent status. Through it, the government monitors temporary residents and helps integrate them into the social and economic system.
Example:
In September 2023, Max arrived in Brussels on a student visa but without a national number — meaning no access to essential services. He couldn’t officially get insurance, open a bank account, or even register at university — bureaucracy blocked him at every step.
In this situation, the BIS number became a real lifesaver: by October 2023, Max received the temporary ID, which opened doors to healthcare, education, and financial services. Thanks to this, he could focus on his studies and live peacefully in Belgium while waiting for his permanent residence permit in March 2024.
Who Gets a BIS Number in Belgium
A BIS number in Belgium is assigned to foreigners who do not have a national number (NN) and who are temporarily staying in the country or are in the process of obtaining permanent residency. This includes, for example, students from other countries coming to study; seasonal workers hired for a limited period; contract specialists; and people recently arrived in Belgium who have not yet completed permanent registration.
Need to arrange your residence in Belgium? Find out more in our article.
The main groups eligible for a BIS number are:
- Foreigners without permanent registration — people who have recently arrived and do not yet have a national number.
- Temporary workers — specialists and seasonal employees working in Belgium under a contract but without permanent residency.
- Foreign students — university and college students temporarily living in Belgium for their studies.
- Specialists and invited experts — foreign professionals on work visas or business trips who need an ID to interact with government bodies.
- Foreigners with temporary residence permits — individuals awaiting permanent status who need a temporary ID to access services.
The BIS number provides basic registration and access to social and medical services until the national number is obtained. It is a temporary solution that helps foreigners live and work legally in Belgium.
The BIS number is issued temporarily and remains valid until the national number or permanent registration is obtained. The validity period can vary, usually from a few months up to a year, depending on the person’s situation and status. If needed, the number can be extended or renewed, but it is not a permanent document.
Tip:
The BIS number is a temporary pass to life in Belgium, so it’s important to track its validity and apply for the national number on time.
What a BIS Number Looks Like
A BIS number consists of 11 digits and serves as a temporary identifier for foreigners in Belgium. The first six digits represent the holder’s birth date in the format DDMMYY (day, month, year). After the birth date comes a three-digit code indicating the type of number and other parameters, and the last two digits are control numbers used to verify the correctness of the number.
Important information about schools for refugees in Belgium is available here.
The difference between a BIS number and a national number (NN) is that the NN also has 11 digits, but its code and control digits are calculated using a different formula. The NN is a permanent number assigned to citizens and residents of Belgium, while the BIS number is temporary and meant for those who have not yet received an NN.
Key features of the BIS number in Belgium:
- Consists of 11 digits — a fixed length that helps standardize identification.
- The first six digits indicate the birth date in DDMMYY format — this allows immediate recognition of the holder’s age.
- The next three digits are a special code indicating the type of number and registration details (e.g., temporary status).
- The last two digits are control digits used to verify the number’s correctness and prevent errors during entry.
- It serves as a temporary identifier issued to foreigners without a national number or permanent registration.
- Does not replace the national number (NN) — once permanent status is granted, the BIS number is replaced by the NN.
- Used for access to social and medical services, tax and administrative procedures.
- Does not grant full rights associated with permanent residency but is necessary for legal stay and work in the country.
- Differs from the national number in its structure and the algorithm for control digits verification.
- Can be renewed or extended if the foreign citizen continues temporary residence.
- Issued both electronically and on paper — often as part of registration documents or ID cards.
Example:
A BIS number may look like this: 230598-123-45, where “230598” is the birth date May 23, 1998, “123” is the special code, and “45” are the control digits.
Verification of the BIS number is based on algorithms that take into account the birth date and code to avoid errors or forgery. This ensures the number is unique and corresponds to a real person. This mechanism helps authorities quickly identify invalid or incorrect records.
How to Get a BIS Number in Belgium
The BIS number in Belgium is issued by registration services and social funds that keep track of foreign nationals. Usually, it is obtained during registration at local municipalities or when applying to social services if the person does not yet have a national number (NN).
The process can happen automatically—for example, when a foreigner is registered in official databases upon starting work or studies—or manually, if the application needs to be submitted independently.
Here is a detailed list of required documents and steps:
- Passport or foreign passport — original and copy required. This document confirms identity and citizenship.
- Visa or temporary residence permit — if available, it should be attached to confirm the legal status in the country.
- Document proving the purpose of stay — for example, an employment contract, invitation from an educational institution, university enrollment, office rental agreement, or other papers explaining the reason for being in Belgium.
- Proof of residence address — rental contract, utility bills (electricity, water, internet), or a letter from the landlord confirming the address.
- Completed application form for the BIS number — can be obtained at the municipality or downloaded from the official website (forms may differ by region).
- Contact local municipal office (commune/gemeente) — the main body where registration and BIS number issuance occur. Address and contacts depend on the place of residence. For example, in Brussels — Hôtel communal de Bruxelles, Rue du Lombard 29, 1000 Brussels.
- Assistance from social services CPAS/OCMW if needed — if registration or documents cause difficulties, social services can help with the application process.
- Official website for registration and info: https://www.ibz.rrn.fgov.be/— find forms, contacts, and registration rules here.
- Hotline phone number: +32 2 801 63 00 — for consultations on registration, identification, and obtaining a BIS number.
- Waiting time: getting a BIS number usually takes from 1 to 4 weeks, depending on the workload of municipal services and the completeness and correctness of documents.
- Possibility of expedited processing: in some cases (e.g., urgent employment), accelerated processing can be requested. This depends on the specific municipality and applicant’s situation.
- Additional advice: it’s better to book an appointment at the municipality in advance, if possible, to avoid queues.
- Regional contacts: if needed, you can find municipal contacts for your region on the official website or through the hotline.
Typically, the BIS number registration takes one to four weeks, but timing varies by region and municipal workload. In large cities such as Brussels or Antwerp, the wait can extend up to a month due to high demand. In quieter regions, the procedure usually takes about 7-14 days.
Tip:
Prepare all documents in advance and carefully check their compliance with requirements — this will significantly reduce waiting time and help avoid refusals.
In some cases, especially when all documents are complete and forms are correctly filled, the number can be issued within a few days. If documents are incomplete or require extra verification, the process may take several months. In urgent situations, such as quick employment, you can request expedited processing.
What is the BIS Number Used For
It is important to always carry your BIS number because it serves as your main identifier with official institutions and employers until you receive a permanent national number. Without it, delays may occur when starting a job, accessing medical care, or dealing with social services. During police or immigration checks, not having a BIS number can cause additional questions and complications.
The BIS number is used for:
- Employment — employers use the BIS number to officially register employees who have not yet received a national number.
- Tax purposes — the BIS number is necessary for tax calculations and filing returns, especially if a person works or lives temporarily in the country.
- Healthcare — the BIS number allows access to medical services, including visiting doctors and obtaining health insurance.
- Social security — it is used to register in the social security system, and to receive benefits and insurance payments.
- Access to government services — the BIS number is needed for interactions with various administrative bodies, obtaining official documents, and registering on government portals.
This number acts as a temporary identifier that allows foreigners and temporary residents to fully participate in life in Belgium until they get a permanent national number. However, it does not grant all rights of citizens — such as voting or working in government institutions.
Example:
In March 2024, Olya moved from Poland to Antwerp and a week later was hospitalized with acute appendicitis. She did not have a national number yet, but thanks to the BIS number she obtained in advance, she was immediately admitted, her documents were processed, and she had surgery without delays. Without this number, receiving help could have been significantly delayed.
Can the BIS Number Be Replaced by a National Number?
The BIS number in Belgium is a temporary identifier and is automatically replaced by a national number (NN) once the person obtains the right to permanent residence. This happens, for example, when receiving an eID card, obtaining a long-term visa, or official registration at the local commune of residence.
How the BIS Number Is Replaced by a National Number in Belgium:
- Obtaining the right to long-term stay (for example, via a D visa, family reunification, work contract, or studies).
- Registering at the local administration of your place of residence (commune/gemeente).
- Transferring your data to the National Register.
- Automatic assignment of a national number (NN) instead of the BIS number.
- Receiving the eID card with the new number.
- Updating your data in official institutions — with your employer, tax office, health insurance fund, and bank.
- The BIS number is cancelled but may remain in the system as a temporary identifier.
The usual timeframe for replacing the BIS number with the NN is between 2 to 6 weeks after completing the registration. Delays often occur due to incomplete documents, data errors, workload in the offices, or technical issues. Proper preparation and timely responses to requests are important.
Frequently Asked Questions (FAQ)
- Is the BIS number mandatory in Belgium?
Yes, the BIS number is required for foreigners who are temporarily staying or working in Belgium without a national number. - How long is the BIS number valid?
It is valid until you receive a national number, usually for several months. - Do I need a BIS number to pay taxes?
Yes, the BIS number is used to register in the tax system until a national number is assigned. - Where can I find my BIS number?
It is mentioned in documents issued by registration offices or social security funds. - Can I use the BIS number to access medical services?
Yes, the BIS number allows access to healthcare and health insurance. - Who issues the BIS number?
It is issued by local registration offices and social security institutions. - Do I need to replace the BIS number with a national number?
Yes, once you receive a residence permit, the BIS number is replaced by a national number. - How fast is the replacement process?
Usually within 2–6 weeks after registration at the local municipality. - Can I apply for a BIS number myself?
In most cases, it is assigned automatically during registration or document submission. - What if the BIS number takes too long to arrive?
You should contact the municipality or the office handling your registration to check the status.
The BIS number in Belgium is a crucial temporary identifier for those who have not yet received their national number. It enables legal employment, tax contributions, and access to healthcare. Understanding its purpose, how to obtain it, and how to replace it helps avoid bureaucratic hurdles and eases your integration into Belgian life. With the right approach, the BIS number becomes your key to a smooth stay and successful adaptation.