IBAN Format Checker
Country
GB
Check Digits
82
Length
22
How it works
An IBAN (International Bank Account Number) is a standardised format for identifying bank accounts internationally, used for cross-border payments in Europe and many other countries. IBANs follow country-specific formats but all share a common structure: 2-letter country code + 2 check digits + up to 30 alphanumeric country-specific account details (BBAN). The IBAN Format Checker validates the format, country code, and checksum of any IBAN.
**Structure** GB29 NWBK 6016 1331 9268 19 (UK example). GB = country code. 29 = check digits. NWBK = sort code bank prefix. 60161331926819 = sort code + account number.
**Validation steps** 1. Move the first 4 characters to the end. 2. Replace each letter with its number value: A=10, B=11, ..., Z=35. 3. Compute the resulting integer modulo 97. 4. Valid if result = 1.
**Why check digit modulo 97?** Mod-97 arithmetic (ISO 7064) is used because 97 is the largest prime number less than 100. This allows the check to detect all single errors, all transpositions of two adjacent characters, and most other common transcription mistakes in a sequence of alphanumeric characters.
**Country coverage** The IBAN system covers 77 countries (as of 2024). The longest IBANs have 34 characters (Malta). The shortest have 15 characters (Norway). The checker validates country-specific length requirements alongside the checksum — a German IBAN must be exactly 22 characters; a UK IBAN exactly 22; a French IBAN exactly 27.
**SWIFT/BIC vs. IBAN** IBAN identifies the specific account. SWIFT/BIC (Bank Identifier Code) identifies the bank. International transfers typically require both. IBAN alone is sufficient for SEPA payments within the Eurozone.
Privacy: all validation runs in the browser. No bank account numbers are transmitted.
Frequently Asked Questions
- As of 2024, 77 countries officially use IBAN for bank account identification. All Eurozone countries (mandatory for SEPA payments), plus UK, Switzerland, Norway, Sweden, Saudi Arabia, UAE, Israel, Jordan, Lebanon, Pakistan, and many others. Notably absent: USA, Canada, Australia, New Zealand, China, Japan, India. For international transfers to US accounts, you use routing number + account number (ABA format); for Australia, BSB (Bank-State-Branch) code + account number.
- SEPA (Single Euro Payments Area) is a payment integration initiative covering 36 European countries (EU + UK + Switzerland + Norway + Iceland + Liechtenstein + Monaco + San Marino + Vatican). SEPA Credit Transfers (SCT) and SEPA Direct Debits (SDD) require IBANs and use SWIFT/BIC codes. Within SEPA, cross-border euro transfers are as cheap and fast as domestic transfers. IBAN standardisation was a prerequisite for SEPA — before IBAN, each country had its own account number format.
- IBAN identifies a specific bank account (the account holder's account number in a standardised format). SWIFT/BIC (Bank Identifier Code) identifies the bank itself: 4-letter bank code + 2-letter country code + 2-char location code + optional 3-char branch code. Example: BARCGB22XXX = Barclays (BARC) + GB (UK) + 22 (London) + XXX (head office). For international wire transfers, you need BOTH: IBAN to identify the destination account, and SWIFT/BIC to route the payment to the correct bank. Within SEPA, only IBAN is required (BIC is optional since 2016).
- The IBAN format checker validates that the country code corresponds to a country that officially uses IBAN and checks the correct length for that country. 'XX29NWBK60161331926819' would fail validation because XX is not a valid IBAN country code. However, the validator cannot confirm that the specific bank code within the BBAN exists, or that the account number is assigned to any real account — only a bank's internal systems can confirm account existence. The validator catches format and checksum errors, not existence errors.