Validate an IBAN
Examples (official IBAN test numbers)
IBAN Length by Country
IBAN Validator verifies International Bank Account Numbers (IBANs) used for international wire transfers. Enter any IBAN to check its structure, validate the check digits using the MOD-97 algorithm, identify the country, and see the BBAN (Basic Bank Account Number) portion. Supports all 77 countries using the IBAN standard and shows country-specific format rules.
IBAN (International Bank Account Number) is a standard for identifying bank accounts internationally, defined by ISO 13616. Format: country code (2 letters) + check digits (2 digits) + BBAN (up to 30 alphanumeric characters). Example: GB29 NWBK 6016 1331 9268 19. The BBAN format varies by country — in the UK it includes sort code and account number, in Germany it includes BLZ (routing) and account number.
IBAN check digit validation (MOD-97): (1) Move the first 4 characters (country code + check digits) to the end. (2) Replace each letter with its numeric value (A=10, B=11, ..., Z=35). (3) Treat the result as a large integer and compute modulo 97. (4) A valid IBAN gives a remainder of 1. This is the same MOD-97 algorithm used in financial systems for check digit validation.
UK IBAN
Result: GB29NWBK60161331926819 → Country: GB ✓, Check: 29 ✓ → MOD-97 = 1 → Valid
German IBAN
Result: DE89370400440532013000 → Country: DE, BLZ: 37040044, Account: 0532013000
Invalid check digit
Result: GB00NWBK60161331926819 → MOD-97 ≠ 1 → ✗ Invalid check digits
How does the IBAN check digit validation work?
MOD-97 algorithm: (1) Move first 4 characters (country + check digits) to end: GB29NWBK60161331926819 → NWBK60161331926819GB29. (2) Replace each letter with its decimal: N=23, W=32, B=11, K=20, G=16, B=11 → 2332111260161331926819162911. (3) Calculate mod 97: 2332111260161331926819162911 mod 97 = 1. A result of 1 = valid. For generating check digits: set them to 00, perform the algorithm, check digit = 98 - (result mod 97).
Which countries use IBAN?
77 countries currently use IBAN (as of 2026). Mandatory within the EU/EEA for all EUR transfers. Middle East: Saudi Arabia, UAE, Qatar, Bahrain, Kuwait, Jordan. North Africa: Egypt, Libya, Tunisia, Algeria. Other: UK, Switzerland, Norway, Israel, Pakistan. Not using IBAN (yet): USA, Canada, Australia, China, Japan, India — these countries use domestic routing numbers (ABA routing number, BSB, etc.) for domestic transfers. For international transfers to these countries, SWIFT/BIC codes are used.
What is a SWIFT/BIC code and how is it different from IBAN?
SWIFT BIC (Bank Identifier Code) identifies a bank institution: 4-letter bank code + 2-letter country code + 2-digit location + optional 3-character branch code. Example: NWBKGB2L (NatWest UK). An IBAN identifies a specific bank account. Both are needed for international wire transfers: IBAN identifies the destination account, SWIFT/BIC identifies the bank. In EU SEPA transfers within the Eurozone, only the IBAN is required (the BIC is derived from the IBAN). For transfers outside SEPA or to non-IBAN countries, the SWIFT BIC is required.
What is SEPA and how does it relate to IBAN?
SEPA (Single Euro Payments Area) is an EU payment integration initiative covering 36 countries that enables euro-denominated bank transfers under the same conditions, rights, and obligations regardless of location (domestic vs. cross-border). SEPA uses IBAN (and previously BIC) as the account identifier. SEPA Credit Transfer (SCT): standard bank-to-bank transfers, settled within 1 business day. SEPA Instant Credit Transfer (SCT Inst): up to 10-second settlement, available 24/7. SEPA Direct Debit (SDD): equivalent to US ACH for recurring payments. SEPA replaced domestic transfer systems like Germany's IBAN transfers.
Why do IBANs have different lengths in different countries?
IBAN length varies by country because the BBAN (Basic Bank Account Number) format is country-specific. Each country's banking system has different routing and account number structures. Shortest: Norway (15 chars total). Longest: Malta (31 chars), Kuwait (30 chars). UK: 22 chars (sort code 6 digits + account 8 digits + bank 4 chars + check 2). Germany: 22 chars (BLZ 8 + account 10). France: 27 chars. The IBAN Registry (maintained by SWIFT on behalf of ISO) specifies the exact format, length, and position of each component for all 77 countries.