Romania IBAN Validator

In short A Romanian IBAN is exactly 24 characters: RO, two check digits, then 4 letters, then 16 letters or digits — so the 4 characters after the check digits are the BIC-derived bank code — AAAA in the example — and the remaining 16 are the account number, 1B31007593840000. Romania is the country where this tool’s own limits show. Its BBAN is four letters of bank code and sixteen ALPHANUMERIC characters — and because the account part accepts both letters and digits, a transposed letter-and-digit pair inside it can survive every check, including mod-97. It is the one such case in 1,183 tested across the registry. The checksum is ISO 7064 MOD-97-10: move the first four characters to the end, turn each letter into its position in the alphabet plus nine, and read the result as one long number, which must leave remainder 1 when divided by 97. That catches every single-character mistake and almost every swap of two neighbouring characters, which is what it was designed for and why an IBAN is worth checking before you pay rather than after. What it cannot do is tell you the account exists, is open, or belongs to the person you think — a random string of the right shape passes about once in 97 tries, and no amount of arithmetic reaches into a bank. This page runs entirely in your browser, so the number you type is not sent anywhere.