IBAN Validator & Parser
Validate and parse IBAN numbers. Check if the IBAN is valid and get the country, BBAN, check digits and the IBAN-friendly format.
Enter an IBAN to validate it.
Valid IBAN examples
MOD-97 algorithm
Validation uses the MOD-97 algorithm (ISO 7064), the official standard for IBAN verification. The rearrangement and remainder calculation uses BigInt for maximum precision.
40+ countries supported
The tool knows the correct IBAN lengths for over 40 countries and checks both the length and the check digit. Incorrect lengths are shown with an explanatory error.
No server, no logs
All validation happens locally in JavaScript. Your IBAN data is never sent to a server — especially important for banking data.
Frequently asked questions
Answers to common questions about IBAN validation
The IBAN (International Bank Account Number) is an internationally standardized account number per ISO 13616. It uniquely identifies a bank account worldwide and is used for cross-border transfers in the SEPA area and internationally. A German IBAN consists of the country code DE, two check digits and the 18-digit BBAN (bank sort code + account number).
In the MOD-97 algorithm, the IBAN is first rearranged (the first 4 characters are moved to the end). Then letters are converted to numbers (A=10, B=11, …, Z=35). The resulting number sequence is calculated modulo 97. A valid IBAN always gives a remainder of 1. Since IBAN numbers can be very long, BigInt is used for exact calculation.
BBAN stands for Basic Bank Account Number. It is the country-specific part of the IBAN after the country code and the two check digits. In Germany, the BBAN consists of the 8-digit bank sort code and the 10-digit account number (18 digits total). In other countries the BBAN may be structured differently.
The MOD-97 check confirms the mathematical correctness of the check digits, but does not mean that the account actually exists or is active. An IBAN can be formally correct but still correspond to a non-existent account. Verifying account existence always requires a query to the respective bank or payment service provider.
The IBAN uniquely identifies the bank account (account number + sort code + country). The BIC (Business Identifier Code, also SWIFT code) identifies the bank itself. For SEPA transfers within the EU, only the IBAN has been required since 2016 — the BIC is automatically determined by the banking system. For international transfers outside SEPA, the BIC is still required.