IBAN Validator

An IBAN (International Bank Account Number) is an internationally agreed system for identifying bank accounts across national borders.

IBAN Structure

[Country Code][Check Digits][BBAN]

• Country Code: 2 letters (ISO 3166-1 alpha-2)
• Check Digits: 2 digits for error detection
• BBAN: Basic Bank Account Number (country-specific format)

Validation Algorithm

1. Move the first 4 characters to the end
2. Replace letters with numbers (A=10, B=11, ..., Z=35)
3. Calculate mod 97 of the resulting number
4. If the remainder is 1, the IBAN is valid

Limitations

This validator checks:

• Format and length for the country
• Check digit validity (mod 97)

It does NOT verify:

• Whether the bank/account actually exists
• Account holder information