IBAN Calculator

What Is an IBAN and How Does It Work?

An IBAN (International Bank Account Number) is a standardized format for identifying bank accounts across national borders. It ensures that international wire transfers reach the correct destination by encoding the country, bank, branch, and account number into a single alphanumeric string. Enter an IBAN in the validator above to check its format, verify the check digits, and identify the country of origin. A valid IBAN confirms the structural correctness of the number but does not verify that the account exists or is active.

IBAN Structure and Format by Country

Every IBAN begins with a two-letter country code, followed by two check digits, then the domestic bank account details. UK: GB29 NWBK 6016 1331 9268 19 (22 characters). Germany: DE89 3704 0044 0532 0130 00 (22 characters). France: FR76 3000 6000 0112 3456 7890 189 (27 characters). Spain: ES91 2100 0418 4502 0005 1332 (24 characters). IBAN length varies by country from 15 characters (Norway) to 34 characters (Malta). The US does not use the IBAN system - American banks use routing numbers and account numbers for domestic transfers and SWIFT/BIC codes for international transactions.

How Does IBAN Validation Work?

The check digits (positions 3-4) are calculated using a modulo 97 operation defined in ISO 7064. To validate: move the first four characters to the end, convert letters to numbers (A=10, B=11, etc.), and calculate modulo 97. If the result is 1, the IBAN is valid. This mathematical check catches 98% of single-character transcription errors and virtually all transposition errors. However, a valid check digit only confirms the number follows the correct format - it does not verify that the bank account actually exists, is open, or belongs to the expected person.

Why Do Banks Require IBAN for International Transfers?

Before IBAN adoption, international transfers frequently failed or were misdirected because each country used different account number formats. A UK sort code and account number, a German BLZ and Kontonummer, and a French RIB all followed different structures. IBAN standardizes these into one universally recognized format. The European Union mandated IBAN for all euro-denominated transfers within SEPA (Single Euro Payments Area). Banks in over 80 countries now use IBAN. Providing the correct IBAN eliminates the most common cause of failed international payments: incorrect or incomplete account identification.

IBAN vs SWIFT/BIC Code: Different Functions

An IBAN identifies the specific bank account receiving funds. A SWIFT/BIC code identifies the bank itself. Both are needed for most international wire transfers. The SWIFT code is 8 or 11 characters (e.g., NWBKGB2L for NatWest UK). The IBAN is the account number. Think of SWIFT as the bank address and IBAN as the apartment number within that building. Some countries that use IBAN derive the bank identification from the IBAN itself, making the SWIFT code redundant in those systems. SEPA transfers within Europe require only the IBAN, not the SWIFT code.

Countries That Use and Do Not Use IBAN

IBAN is used across Europe, the Middle East, North Africa, the Caribbean, and parts of Central America and Asia. All 36 SEPA member countries require IBAN. Major non-SEPA adopters include Saudi Arabia, UAE, Qatar, Brazil, Pakistan, and Turkey. Notable countries that do NOT use IBAN: United States, Canada, Australia, New Zealand, China, Japan, India, and South Korea. When sending money to non-IBAN countries, you use the SWIFT code plus the local account number format. When receiving from IBAN countries into a US bank, the sender enters your bank SWIFT code and account number rather than an IBAN.

Common IBAN Errors and How to Avoid Them

Transposing digits: swapping two adjacent numbers is the most frequent manual entry error. Always copy and paste IBAN numbers electronically rather than typing them manually. Including spaces: IBANs are written with spaces for readability (GB29 NWBK 6016 1331 9268 19) but must be entered without spaces in most banking systems. Using the wrong country format: entering a 22-character IBAN for a country that requires 27 characters. Confusing zero and the letter O or the number one and lowercase L: some fonts make these indistinguishable. Verify the IBAN using a validator tool before initiating a transfer to catch these errors before they cause a failed or misdirected payment.

SEPA Transfers and the Role of IBAN in Europe

SEPA (Single Euro Payments Area) enables euro-denominated transfers between 36 European countries with the same ease and cost as domestic payments. SEPA Credit Transfers typically process within one business day and require only the recipient IBAN - no SWIFT code needed. SEPA Direct Debits allow businesses to collect payments from customer bank accounts across borders using IBAN authorization. The cost of SEPA transfers is regulated to be the same as domestic transfers, making a payment from Germany to France as inexpensive as a transfer within Germany. This system has largely eliminated the high fees and multi-day delays that previously characterized cross-border European banking.

Frequently asked questions