What is an IBAN calculator?
An IBAN calculator converts national account details into an International Bank Account Number. Choose Germany, Austria or Switzerland, enter the bank identifier and account number, and iban24 calculates the checksum and complete IBAN. When matching bank data is available, the result also includes the bank name and BIC.
The calculation is useful when older documents contain only domestic account details. It does not replace an IBAN issued by your bank, so compare the result with an account statement or online banking before using it for an important transaction.
How to calculate an IBAN
- Select the country in which the account is held.
- Enter the national bank code. For Swiss accounts, use the IID or clearing number.
- Enter the account number without unnecessary spaces.
- Select Calculate IBAN.
- Review the identified bank and copy the result.
Each supported country uses a different account structure. German IBANs contain an eight-digit bank code, while Austrian and Swiss identifiers contain five digits. The tool applies the correct length, padding and checksum rules for the selected country.
What the checksum does
The two digits after the country code form the IBAN checksum. It is calculated using the international Modulo 97 method and helps payment systems detect common typing errors. A valid checksum confirms that the number is structurally plausible; it does not prove that the account exists, is active or belongs to a particular person.
Bank and BIC information
iban24 compares the bank identifier with available official bank data for Germany, Austria and Switzerland. If a match exists, the bank name, BIC and available branch information are displayed. Bank datasets change over time, so official information from the bank remains authoritative.
Privacy and responsible use
The entered bank details are processed for the calculation and are not stored permanently. Only calculate account details that you are permitted to use, and verify every result before including it in invoices, payment instructions or business records.