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Calculate Iban From Account Number

Reviewed by Calculator Editorial Team

An International Bank Account Number (IBAN) is a standardized way to identify bank accounts across European countries. While the IBAN itself is not directly calculated from an account number, it's constructed using the account number along with other banking information. This guide explains the process and provides a calculator to help you understand how IBANs are formed.

What is an IBAN?

An IBAN (International Bank Account Number) is an internationally agreed standard for identifying bank accounts across European countries. It's a unique code that identifies the country, bank, and account number, making it easier to transfer money internationally.

The IBAN consists of up to 34 alphanumeric characters, structured as follows:

  • Country Code (2 letters)
  • Check digits (2 digits)
  • Bank account number (up to 30 characters)

The check digits are calculated using a specific algorithm to ensure the IBAN is valid. While the IBAN isn't directly calculated from just an account number, it's constructed using the account number along with other banking information.

How to Calculate IBAN from Account Number

Calculating an IBAN from an account number involves several steps:

  1. Identify the country code (2 letters)
  2. Determine the bank code (typically 4-8 digits)
  3. Include the branch code (if applicable)
  4. Add the account number
  5. Calculate the check digits
  6. Combine all elements into the IBAN format

Note: The exact format varies by country. Some countries may require additional elements like national check digits or account type indicators.

The check digits are calculated using a specific algorithm that converts the IBAN into a number and performs a modulo 97 operation to verify its validity.

IBAN Calculation Formula

The IBAN calculation involves these key steps:

1. Rearrange the IBAN: Move the first four characters to the end
2. Convert letters to numbers (A=10, B=11, ..., Z=35)
3. Interpret the string as a number
4. Calculate modulo 97 of this number
5. Subtract the result from 98
6. Use the result as the check digits

For example, if the rearranged IBAN string converts to the number 12345678901234567890, the check digits would be calculated as:

Check digits = 98 - (12345678901234567890 mod 97)

Worked Example

Let's calculate an example IBAN for a German bank account:

  1. Country code: DE
  2. Bank code: 12345678
  3. Account number: 1234567890

The IBAN would be constructed as: DE00 1234 5678 0000 1234 5678 90

Using the calculation formula, we would:

  1. Rearrange to: 1234567800001234567890DE00
  2. Convert letters to numbers: 1234567800001234567890131400
  3. Calculate modulo 97: 12345678901234567890131400 mod 97 = 1
  4. Check digits: 98 - 1 = 97
  5. Final IBAN: DE97 1234 5678 0000 1234 5678 90

Frequently Asked Questions

What is the difference between IBAN and account number?
An IBAN is a standardized international identifier that includes the country code, bank code, and account number. The account number is just one part of the IBAN.
Can I calculate an IBAN without knowing the bank code?
No, the bank code is required to construct a valid IBAN. Without it, you cannot accurately calculate the IBAN.
How do I verify if an IBAN is correct?
You can verify an IBAN using the check digits calculation. The IBAN should pass the modulo 97 test to be valid.
Are IBANs used outside Europe?
While IBANs are primarily used in Europe, some non-European countries have adopted them for international transactions.
Can I use this calculator for any country's IBAN?
This calculator provides a general framework, but the exact format varies by country. Always refer to your country's banking regulations for precise requirements.