Calculate IBAN from bank data

Generate IBAN from bank code and account number

Generate an IBAN directly in the browser from a country, bank code and account number. IBAN-Test calculates the country-specific IBAN structure and check digits for testing and further validation.

Generate IBAN now Check an existing IBAN
Calculate quicklyEnter the country, bank code and account number to calculate an IBAN.
Validate directlyCheck the result for structure, checksum and available bank data.
Available via APIAutomate IBAN generation for tests, forms and internal processes.

generate IBAN

The check determines whether an IBAN can actually have been issued by a bank.

Recognize typographical errors or deliberate incorrect entries in good time and thereby save unnecessary costs for returned direct debits.

Simply enter your sort code and account number and the software will then generate your IBAN.

When the IBAN generator helps

The IBAN generator calculates an IBAN from a country, bank code and account number. It is useful when existing bank details need to be converted into the country-specific IBAN format for testing or further processing.

Calculate from bank data

Enter the country, bank code and account number. IBAN-Test creates the matching IBAN structure when generation rules are available.

Check the result

Validate the generated IBAN to confirm its length, country structure, check digits and available bank data.

Automate workflows

For recurring tests, forms and internal systems, IBAN generation is also available through the API.

How an IBAN is generated

  1. 1. Apply the country formatEach country defines the length and structure of its domestic bank account number inside the IBAN.
  2. 2. Build the BBANThe bank code and account number are placed into the country-specific Basic Bank Account Number structure.
  3. 3. Calculate check digitsThe two IBAN check digits are calculated with the international MOD-97 method.
  4. 4. Validate before useThe result should be checked again and confirmed with the account-holding bank before real payments.

Important: Generating an IBAN does not create a bank account and does not confirm that an account exists. The tool calculates a formally matching IBAN from the entered data.

For country-specific structure and available checks, see the IBAN profiles for Ireland, United Kingdom and Netherlands.

Frequently asked questions about generating an IBAN

Answers about IBAN structure, generation, validation and invalid bank data are available in the FAQ about IBAN validation and generation.

What is an IBAN?
IBAN basics: structure, purpose and check digits.

An IBAN is an International Bank Account Number. It standardizes bank account details for domestic and international payments and helps identify bank accounts reliably.

An IBAN consists of a country code, two check digits and a country-specific account identifier. In Germany, this identifier includes bank code and account number.

IBAN-Test checks structure, length and check digits. For selected countries, additional validation against bank directories is available.

What does the IBAN check validate?

The check validates the country code, length, permitted characters and IBAN checksum. Depending on the country, it also checks available bank directories and national account checksums.

This detects many input errors but does not confirm that an account exists, who owns it or whether a payment can be executed. Check the IBAN again

How does the IBAN generator work?
Generate and validate an IBAN from country code, bank code and account number.

The IBAN generator creates an IBAN from country-specific bank details. For Germany, this means bank code and account number.

IBAN-Test calculates the check digits, formats the IBAN and, where possible, validates the underlying bank data. This means the result is not only formatted correctly, but also checked for plausibility.

For automated processes, IBAN generation is also available through the API.

What should I do if an IBAN is invalid?

Compare the complete IBAN with online banking or a recent bank statement. Look for missing characters, transposed digits and confusion between letters and numbers, such as O and 0. Do not guess replacement digits.

Ordinary spaces are removed automatically. If the IBAN remains invalid, ask the account holder or their bank to confirm the bank details. Check the IBAN again

If confirmed details still fail, tell support the country and exact error message, initially without a complete IBAN or API token. Contact support. For technical API problems: API error codes.

What is the difference between IBAN check and bank data validation?

The format check validates the IBAN structure, length and checksum. Bank data validation additionally checks whether the bank identifier appears in the available directories.

The depth of validation varies by country: bank directories and national checksum rules are not equally available everywhere. A successful format check is therefore not the same as a full bank data check. Checks available by country

Can I validate a BIC?

Yes, the API checks the BIC format and returns available bank details. A BIC has 8 or 11 characters. Compare it with the bank’s information and check for missing characters or transposed digits.

A valid format does not guarantee a bank directory match. Missing bank details therefore do not automatically make a BIC invalid. If in doubt, ask the bank to confirm it. API documentation

Why does my IBAN have the wrong length?

Each supported country format has a fixed length, determined by the country code at the start of the IBAN. For example, a German IBAN has 22 characters.

Copy the complete IBAN from the bank’s information and check whether characters were lost or added during copying. Leading zeros are part of the IBAN. Do not add or remove digits by guessing. Check the IBAN again

What does an invalid IBAN checksum mean?

The two digits after the country code do not mathematically match the rest of the IBAN. A typo, transposed digits or an incomplete entry is often the cause.

Compare the entire IBAN with the bank’s information. Do not change just the check digits to obtain a valid result: that would not confirm the intended bank details. Check the IBAN again

Why is a bank code not recognised?

The bank identifier was not found in the available bank directory or does not match the country format rules. First check the country code, bank identifier and leading zeros.

Older bank details after a merger or change may also require confirmation from the bank. Confirm the current details before changing anything. A missing match alone does not prove that the account does not exist. Check the IBAN again

Why is an account number invalid despite the correct format?

The right length alone is not enough. Where national checksum procedures are available, these are checked too. The account number must match the rules and the supplied bank identifier.

Check the bank code and account number together against the bank’s information, including leading zeros. If confirmed details still fail, contact support. This is a plausibility check, not a lookup of the actual account. Contact support

Bank data validation

Bank directory checks for 40 countries

IBAN-Test goes beyond checksum-only validation. For these countries, we check the bank identifier against available bank directories and return bank details such as institution, city and BIC when available. See how IBAN validation works.

ALAlbania ADAndorra ATAustria BEBelgium BGBulgaria HRCroatia CYCyprus CZCzech Republic DKDenmark EEEstonia FIFinland FRFrance DEGermany GIGibraltar GRGreece HUHungary ISIceland IEIreland ITItaly LVLatvia LILiechtenstein LTLithuania LULuxembourg MTMalta MDMoldova MEMontenegro NLNetherlands MKNorth Macedonia NONorway PLPoland PTPortugal RORomania SMSan Marino RSSerbia SKSlovakia SISlovenia ESSpain SESweden CHSwitzerland VAVatican City

IBAN syntax check

Format checks for 115 IBAN formats

Check IBANs for a valid structure, correct length and checksum. This helps you catch typos and transposed digits before a payment fails. Additional bank validation against real bank directories is available for the countries listed above.

MCP Server for AI Agents – Connect AI clients to IBAN validation tools – https://www.iban-test.eu/mcp – API documentation