IBAN Validator

Validate International Bank Account Numbers using the official IBAN checksum algorithm. Instant, free, and 100% client-side.

Enter IBAN

IBAN Number

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IBAN Validator

An International Bank Account Number (IBAN) is a standardized format for identifying bank accounts across national borders. Originally developed in Europe, IBAN is now used by over 70 countries worldwide to facilitate international wire transfers.

How IBAN Validation Works

IBAN validation uses a modulo-97 checksum algorithm:

Move the first 4 characters (country code + check digits) to the end of the string.
Convert all letters to numbers (A=10, B=11, ..., Z=35).
Compute the numeric value modulo 97.
A valid IBAN must yield a remainder of exactly 1.

IBAN Structure

Country Code (2 letters): ISO 3166-1 alpha-2 country code (e.g., GB, DE, FR)
Check Digits (2 digits): Calculated using the MOD-97 algorithm
BBAN: Basic Bank Account Number — the account number within the country

Privacy & Security

All validation is performed entirely in your browser using JavaScript. No IBAN data is transmitted to any server.

How IBAN Validation Works

IBAN validation uses a modulo-97 checksum algorithm:

Move the first 4 characters (country code + check digits) to the end of the string.
Convert all letters to numbers (A=10, B=11, ..., Z=35).
Compute the numeric value modulo 97.
A valid IBAN must yield a remainder of exactly 1.

IBAN Structure

Country Code (2 letters): ISO 3166-1 alpha-2 country code (e.g., GB, DE, FR)
Check Digits (2 digits): Calculated using the MOD-97 algorithm
BBAN: Basic Bank Account Number — the account number within the country

Privacy & Security

All validation is performed entirely in your browser using JavaScript. No IBAN data is transmitted to any server.