Validate a French IBAN in your browser
A French IBAN is the 27-character account identifier used across SEPA transfers and e-mandat / RIB workflows in France. Unlike most countries, France layers a second, national check — the Clé RIB — on top of the international MOD-97 checksum. This tool runs both, entirely on your device.
How it works
The French IBAN layout is FR + 2 check digits + 5-digit code banque + 5-digit code guichet + 11-character account + 2-digit Clé RIB.
The international checksum (ISO 7064 MOD-97-10): move the first four characters to the end, replace letters with two-digit values (A=10 … Z=35), and confirm the number modulo 97 equals 1.
The Clé RIB uses a French-specific letter table (A,J→1, B,K,S→2, and so on) to convert any letters in the account number to digits, then checks:
(89 × banque + 15 × guichet + 3 × compte + clé) mod 97 == 0where each component is reduced modulo 97 first. The tool computes the expected relationship and reports pass or fail for each test separately.
Example and notes
The sample IBAN FR14 2004 1010 0505 0001 3M02 606 contains the letter M inside the account number — the RIB table maps it to 4 for the key calculation. If you only validate the MOD-97 checksum you can miss a transposed account digit, which is exactly why French banks rely on the Clé RIB as well. A valid result here confirms structure and both checksums, not that the account is open.