IBAN Validator: Check Any International Bank Account Number

IBAN structure breakdown

An IBAN has three components:

1. Country code (2 letters): ISO 3166-1 alpha-2, e.g. GB, DE
2. Check digits (2 digits): computed via mod-97 for error detection
3. BBAN (Basic Bank Account Number, up to 30 chars): the domestic account identifier

Annotated example: GB82 WEST 1234 5698 7654 32

• GB = United Kingdom
• 82 = check digits
• WEST 1234 5698 7654 32 = BBAN (sort code + account number)

Country IBAN lengths

IBAN vs. SWIFT/BIC

These two identifiers serve different purposes and both are required for international wire transfers:

• IBAN: identifies a specific bank account (the destination). Up to 34 alphanumeric characters.
• SWIFT/BIC (Bank Identifier Code): identifies the bank itself. 8 or 11 characters (bank code + country + location + optional branch).

Example: BIC DEUTDEDB identifies Deutsche Bank Germany; the IBAN provides the specific account within that bank.

IBAN Validator

Enter any IBAN to validate its country code, expected length, and mod-97 checksum. Spaces are ignored and lowercase input is accepted.

What is an IBAN?

An International Bank Account Number (IBAN) is a standardised system of identifying bank accounts across national borders. It was developed by the International Organisation for Standardisation (ISO) and the European Committee for Banking Standards (ECBS).

How validation works

1. The two-letter country code is checked against the ISO 13616 registry.
2. The total length is verified against the expected length for that country.
3. The first four characters are moved to the end, letters replaced with numbers (A=10…Z=35), and the resulting number is divided by 97. A valid IBAN produces a remainder of 1.

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