What is IBAN?
IBAN (International Bank Account Number) is a standardized identifier for bank accounts used in international payments.
IBAN Structure
An IBAN starts with a two-letter country code, two check digits, and a country-specific BBAN.
Checksum Validation
IBAN validity is checked with the ISO 13616 mod-97 algorithm.
- Remove spaces and move the first four characters to the end
- Convert letters to numbers (A=10, B=11, …, Z=35)
- Compute mod 97; a valid IBAN leaves a remainder of 1
Each country defines a fixed length and structure for the BBAN portion.