Luxembourg IBAN Format (LU) — Structure, Length & Validator

The Luxembourg IBAN is one of the shortest eurozone IBANs at 20 characters. As a global financial centre hosting over 140 banks, Luxembourg processes a disproportionately large volume of cross-border SEPA and SWIFT transactions for its size. The compact LU IBAN format makes it straightforward to validate, but the 3-digit bank code is unique to Luxembourg and worth understanding.

Luxembourg IBAN at a Glance

• Country code: LU
• Total length: 20 characters (always)
• Format: LUkk bbb cccccccccccccc
• BBAN length: 16 characters (3 digits + 13 alphanumeric)
• Currency: Euro (EUR)
• SEPA member: Yes (eurozone founding member)

Luxembourg IBAN Structure Explained

A Luxembourg IBAN has three BBAN components within its 20-character body:

1. Country Code, LU (2 characters)

The ISO 3166-1 alpha-2 code for Luxembourg. Every Luxembourg IBAN begins with LU.

2. Check Digits, kk (2 digits)

Two decimal digits calculated via the MOD-97 algorithm over the full BBAN. They catch transcription errors and are fixed at account creation.

3. Bank Code, bbb (3 digits)

A 3-digit code assigned by the Banque centrale du Luxembourg (BCL) that uniquely identifies the institution. Common Luxembourg bank codes:

• 001, Banque et Caisse d'Épargne de l'État (BCEE / Spuerkeess)
• 002, Banque Internationale à Luxembourg (BIL)
• 003, BGL BNP Paribas
• 008, Banque de Luxembourg
• 009, Banque Raiffeisen
• 014, ING Luxembourg
• 111, POST Luxembourg

4. Account Number, cccccccccccccc (13 alphanumeric characters)

A 13-character account number that may contain both uppercase letters and digits. The alphanumeric account field is a legacy of Luxembourg's domestic banking system. In practice, most modern Luxembourg IBANs use only digits in this field, but letters remain valid and your validation must accept them.

Real Luxembourg IBAN Example

LU28 0019 4006 4475 0000

• Country: LU
• Check digits: 28
• Bank code: 001 (BCEE / Spuerkeess)
• Account number: 9400644750000

Electronic format: LU280019400644750000

How Luxembourg IBAN Validation Works

1. Country code: First two characters must be LU.
2. Length: Exactly 20 characters after removing spaces.
3. Character types: Positions 3–4 are digits; positions 5–7 are digits (bank code); positions 8–20 may be digits or uppercase letters.
4. MOD-97: Rearrange the first four characters to the end, convert all letters to numbers (A=10…Z=35), compute modulo 97. Result must equal 1.

The ibanchecker.cash validator performs all checks instantly. Paste any Luxembourg IBAN to see the bank name, BIC, and a full BBAN breakdown.

Luxembourg as a Financial Hub

Luxembourg is home to one of the world's largest investment fund industries and hosts the European headquarters of many global banks. It is a founding eurozone and SEPA member. For SEPA Credit Transfers within the SEPA zone, the LU IBAN alone is sufficient. For international transfers outside SEPA, the bank's BIC must accompany the IBAN. Find any Luxembourg bank's BIC with the ibanchecker.cash SWIFT directory.

Common Luxembourg IBAN Mistakes

Rejecting Alphanumeric Account Fields

Although rare, Luxembourg account numbers can contain uppercase letters. Validation systems that only accept digits in the account portion will incorrectly reject valid Luxembourg IBANs. Always check for alphanumeric BBAN support when implementing Luxembourg IBAN validation.

Confusing LU with LT (Lithuania)

Luxembourg (LU) and Lithuania (LT) are frequently confused. Both are 20-character IBANs with entirely numeric BBANs in practice, and their country codes differ by only one letter. Always verify the country code before routing a payment.

Validating Luxembourg IBANs in Bulk

Investment managers, fund administrators, and finance teams with Luxembourg counterparties can validate multiple IBANs at once using the ibanchecker.cash bulk checker. Upload a CSV with up to 100 IBANs and get instant validation results, bank names, and BIC codes per row.

Sources & References

• SWIFT IBAN Registry — Official IBAN country format specifications
• ISO 13616 — IBAN international standard
• Banque centrale du Luxembourg (BCL) — Luxembourg central bank and bank code registry
• EPC SEPA Participants — SEPA scheme participants register
• ECB TARGET2 — Eurozone payment system information

Last updated: June 2026