Validate International Bank Account Numbers using the ISO 13616 mod-97 checksum and extract country, check digits, and BBAN
An IBAN (International Bank Account Number, ISO 13616) starts with a 2-letter country code, 2 check digits, and a country-specific BBAN. Validation uses mod-97: rearrange the IBAN by moving the first 4 chars to the end, replace each letter with its position-based number (A=10, B=11…Z=35), then divide as a large integer by 97. The remainder must be 1.
All 70+ registered IBAN-issuing countries are supported with length validation.