France IBAN validator
How the IBAN format works
- Format
- FR + 2 check digits + 5-digit bank code + 5-digit branch code + 11-char account number + 2-digit RIB key (27 chars)
- Example
- FR1420041010050500013M02606
Things to watch for
- 27 characters total
- The account number segment can contain letters, not just digits
^FR[0-9]{2}[0-9]{5}[0-9]{5}[0-9A-Z]{11}[0-9]{2}$A French IBAN is 27 characters: “FR”, two check digits, a 5-digit bank code (code banque), a 5-digit branch code (code guichet), an 11-character account number that can mix digits and letters, and a 2-digit national check value called the clé RIB. That clé RIB predates IBAN — it comes from France’s older RIB (relevé d’identité bancaire) format and is calculated from the bank, branch, and account segments using a formula specific to French banking, layered underneath the mod-97 checksum that the IBAN itself carries. Anyone paying a French landlord, invoicing a French client, or converting an old RIB to IBAN for a SEPA transfer needs all 27 characters in the right segment, including the often-overlooked possibility of letters inside the account number.
How this validator works
This tool checks the “FR” prefix, confirms the code banque block is 5 digits, the code guichet block is 5 digits, the account-number block is 11 alphanumeric characters, and the clé RIB block is 2 digits, then runs the real mod-97 checksum (ISO 7064) French banks use to generate a valid IBAN — entirely client-side, nothing sent to a server, no signup required.
What a pass doesn’t tell you
A pass confirms the 27 characters are correctly formed and internally consistent — not that the account is open, active, or belongs to the person you expect. This tool doesn’t resolve the code banque to a bank name and never contacts Banque de France or any commercial bank. If a French IBAN converted from an old RIB fails, check first whether a letter in the account-number segment was mistakenly read as a digit (or vice versa) during the conversion — that’s a common source of error unique to the French format.
Scope: French 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 is the 'clé RIB' at the end of a French IBAN?
It's a 2-digit national check value, distinct from the IBAN's own mod-97 check digits near the start, computed from the bank code, branch code, and account number using France's own domestic formula — a French account number effectively carries two independent layers of error detection.
Can the account-number segment of a French IBAN contain letters?
Yes. Unlike the bank code and branch code blocks, which are always digits, the 11-character account number segment can include uppercase letters — so a French IBAN isn't purely numeric after the country code and check digits, which trips up validators built only for all-digit formats.
Does this tool separately recompute the clé RIB as its own step?
This tool runs the IBAN-level mod-97 (ISO 7064) checksum on the full 27 characters. It doesn't isolate and recompute the domestic clé RIB algorithm as a distinct step, and it doesn't confirm the account is open or belongs to anyone — that requires your bank or Banque de France.