Luxembourg IBAN validator
How the IBAN format works
- Format
- LU + 2 check digits + 3-digit bank code + 13-char account number (20 chars)
- Example
- LU280019400644750000
Things to watch for
- 20 characters total
^LU[0-9]{2}[0-9]{3}[0-9A-Z]{13}$A Luxembourg IBAN is 20 characters: “LU”, two check digits, a compact 3-digit bank code, and a 13-character account number that can mix letters and digits. The 3-digit bank code is one of the shortest in Europe, a natural consequence of Luxembourg’s small, concentrated banking sector needing far fewer unique codes than a country the size of Germany or France — the code identifies the institution outright, with the following 13-character block carrying the rest of the account detail, letters included. Anyone paying a Luxembourg-based supplier, dealing with the country’s large fund-administration and private-banking sector, or filling in a SEPA transfer form needs all 20 characters correct, watching in particular for letters folded into the account-number segment.
How this validator works
This tool checks the “LU” prefix, confirms the bank-code block is 3 digits and the account-number block is 13 alphanumeric characters, then runs the real mod-97 checksum (ISO 7064) Luxembourg banks use to generate a valid IBAN — entirely client-side in your browser, nothing sent to a server, no signup required.
What a pass doesn’t tell you
A pass confirms the 20 characters are correctly formed and internally consistent — not that the account exists, is open, or belongs to whoever you expect. This tool does no bank-code-to-bank-name resolution and never contacts the Commission de Surveillance du Secteur Financier or any commercial bank. If a Luxembourg IBAN fails, check the account-number segment first for a letter that may have been misread as a digit (or vice versa) when copying — that mixed alphanumeric block is the most common source of transcription error in this format.
Scope: Luxembourg IBAN structure and mod-97 checksum validation only — not payment processing, bank-name lookup, or confirming an account is active, none of which a client-side check can establish. Use this validator to catch a typo before a transfer fails; use your bank to confirm the account itself.
Content last reviewed 2026-07-07.
IBAN FAQ
What does a Luxembourg IBAN encode?
20 characters: 'LU', two check digits, a 3-digit bank code, and a 13-character account number that can include letters as well as digits — for example LU280019400644750000.
Why is Luxembourg's bank code only 3 digits when many countries use longer codes?
Luxembourg's domestic banking sector is small and concentrated relative to larger EU economies, so its national bank-code registry never needed more than 3 digits to uniquely identify each institution — a direct reflection of the country's size rather than any simplification in the IBAN format itself.
Does a pass confirm the account is held at a real Luxembourg bank?
No. This tool checks structure and the mod-97 checksum only, with no bank-code-to-bank-name lookup and no contact with the Commission de Surveillance du Secteur Financier or any bank. Confirming the account is open requires the account holder or your own bank.