IBAN & SEPA
IBAN Standard (ISO 13616)
ISO 13616 is the international standard that defines the structure and validation rules for the IBAN (International Bank Account Number). Published by the International Organization for Standardization (ISO), it specifies how an IBAN is composed from a country code, check digits, and a domestic BBAN, as well as how to verify its integrity mathematically.
The standard has two parts. ISO 13616-1 specifies the IBAN structure: a maximum of 34 alphanumeric characters beginning with a two-letter country code and two check digits, followed by the country-specific BBAN. ISO 13616-2 covers the registration process — SWIFT acts as the Registration Authority, maintaining the official IBAN Registry that maps each country to its BBAN format. Validation is performed using the MOD-97 algorithm, where the IBAN is rearranged, letters are converted to numbers, and the result must be divisible by 97 with a remainder of 1.
ISO 13616 is the foundation that makes IBANs interoperable worldwide. Without a single standard, every country would use its own account format, making cross-border validation impossible. Banks, payment processors, and fintech platforms all rely on this standard to validate IBANs consistently — and so does every IBAN checker, including BankCheck.
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