International Bank Account Number (IBAN) UK Guide. IBAN or international bank account number is a system of assigning a unique number to an individual, using which the person’s banking information or details would be globally or internationally recognized. Lookup, validate and verify BIN and IIN numbers of any debit or credit card by accessing the card’s registered details in our BIN list. The bank identification number (BIN) is the first 6 or 8 numbers of a debit or credit card number. The BIN is also known as the issuer identification number (IIN).