Cal11 calculator
Search calculator...

Account Number to Iban Calculator

Reviewed by Calculator Editorial Team

An International Bank Account Number (IBAN) is a standardized format for identifying bank accounts across national borders. This calculator helps you convert a domestic account number to the IBAN format by adding the country code, check digits, and formatting the account number according to international standards.

How to Convert Account Number to IBAN

The IBAN format consists of a country code (2 letters), check digits (2 digits), and the Basic Bank Account Number (BBAN) which includes the domestic bank code, branch code, and account number. Here's how to convert a domestic account number to IBAN:

  1. Identify the country code for your bank account (e.g., GB for United Kingdom, DE for Germany).
  2. Format the BBAN by removing any spaces or special characters.
  3. Combine the country code, check digits (calculated), and BBAN.
  4. Format the IBAN by grouping the characters into blocks of 4, separated by spaces.

Note: The check digits are calculated using the IBAN algorithm, which involves converting letters to numbers, rearranging the digits, and performing modulo operations.

Step-by-Step Conversion Process

Let's walk through an example of converting a domestic account number to IBAN:

  1. Start with the domestic account number: 12345678
  2. Add the bank code and branch code: GB33NWBK60161331926819
  3. Calculate the check digits: 33
  4. Combine to form the IBAN: GB33NWBK60161331926819
  5. Format with spaces: GB33 NWBK 6016 1331 9268 19

The final IBAN is GB33 NWBK 6016 1331 9268 19, which can be used for international transactions.

Formula Used

The IBAN is calculated using the following formula:

IBAN = Country Code + Check Digits + BBAN

Where:

  • Country Code - 2-letter ISO country code
  • Check Digits - 2-digit number calculated using the IBAN algorithm
  • BBAN - Basic Bank Account Number (domestic bank code, branch code, and account number)

The check digits are calculated by:

  1. Converting each letter in the IBAN to its corresponding number (A=10, B=11, ..., Z=35).
  2. Moving the first four characters (country code + check digits) to the end of the string.
  3. Converting the resulting string to a number.
  4. Calculating 98 minus the remainder of the division of this number by 97.
  5. Formatting the result as a two-digit number.

Worked Examples

Let's look at two examples of converting account numbers to IBAN format.

Example 1: UK Account Number

Domestic account number: 12345678

Bank code: NWBK

Branch code: 601613

Country code: GB

  1. Combine bank code, branch code, and account number: NWBK60161331926819
  2. Calculate check digits: 33
  3. Form IBAN: GB33NWBK60161331926819
  4. Format with spaces: GB33 NWBK 6016 1331 9268 19

Example 2: German Account Number

Domestic account number: 12345678

Bank code: DEUT

Branch code: 10010000

Country code: DE

  1. Combine bank code, branch code, and account number: DEUT1001000012345678
  2. Calculate check digits: 89
  3. Form IBAN: DE89DEUT1001000012345678
  4. Format with spaces: DE89 DEUT 1001 0000 1234 5678
Comparison of Domestic Account Numbers and IBANs
Country Domestic Account Number IBAN
United Kingdom 12345678 GB33 NWBK 6016 1331 9268 19
Germany 12345678 DE89 DEUT 1001 0000 1234 5678

Frequently Asked Questions

What is an IBAN?

An IBAN (International Bank Account Number) is an internationally agreed system of identifying bank accounts across national borders. It eliminates the need to re-enter banking information when making international transfers.

How do I find my IBAN?

Your IBAN is typically provided by your bank. It can be found on bank statements, account information documents, or by contacting your bank directly. You can also use our calculator to convert your domestic account number to IBAN format.

Is the IBAN the same as a SWIFT code?

No, the IBAN and SWIFT code serve different purposes. The IBAN identifies the account, while the SWIFT code identifies the bank. Both are needed for international transfers.

Can I use the IBAN for all international transfers?

Yes, the IBAN is the preferred method for identifying accounts in international transactions. It simplifies the process by providing a standardized format that works across different countries.