Austrian IBAN Format (AT): Structure, Bankleitzahl, and Validation Examples

The Austrian IBAN is 20 characters long and follows a clean, straightforward structure: a 5-digit Bankleitzahl (routing code) and an 11-digit account number. Austria is a eurozone and SEPA member, and Austrian IBANs are processed daily in the DACH region (Germany, Austria, Switzerland) as well as across the broader EU. The Austrian format is deliberately similar to the German format, making it approachable for anyone already familiar with DE IBANs.

Austrian IBAN at a Glance

• Country code: AT
• Total length: 20 characters (always)
• Format: ATkk bbbbb ccccccccccc
• BBAN length: 16 digits
• Character types: digits only after the country code

Austrian IBAN Structure Explained

1. Country Code, AT (2 characters)

The ISO 3166-1 alpha-2 code for Austria. Every Austrian IBAN begins with AT.

2. Check Digits, kk (2 digits)

Two decimal digits calculated using the MOD-97 algorithm. Standard across all IBANs.

3. Bankleitzahl, bbbbb (5 digits)

The Bankleitzahl (BLZ) is Austria's 5-digit bank routing code, assigned by the Austrian National Bank (OeNB). It identifies the specific bank. Note that Austria's BLZ is 5 digits while Germany's BLZ is 8 digits, they are different systems despite the shared name. Common Austrian BLZ codes:

• 20111, Erste Bank der oesterreichischen Sparkassen
• 12000, UniCredit Bank Austria
• 31000, Raiffeisen Bank International
• 60000, BAWAG P.S.K. (the historic P.S.K. code)

4. Account Number, ccccccccccc (11 digits)

The 11-digit account number identifying the individual account at that bank. Austrian account numbers are zero-padded on the left if the original account number has fewer than 11 digits.

Austrian IBAN Example Explained

AT23 2011 1002 3457 3201

• Country: AT
• Check digits: 23
• Bankleitzahl: 20111 (Erste Bank)
• Account number: 00234573201

Second Example, Bank Austria

AT48 1200 0006 2534 9870

• Country: AT
• Check digits: 48
• Bankleitzahl: 12000 (UniCredit Bank Austria)
• Account number: 00625349870 (zero-padded)

How Austrian IBAN Validation Works

1. Country code check: First two characters must be exactly AT.
2. Length check: Total character count (spaces removed) must be exactly 20. This is shorter than the German IBAN (22 characters) despite both using a Bankleitzahl.
3. Character type check: Positions 3–20 must all be decimal digits.
4. MOD-97 check: Move the first four characters to the end, replace letters with numbers, compute modulo 97. Result must equal 1.

The ibanchecker.cash validator validates Austrian IBANs instantly and displays the Bankleitzahl, bank name, and account number.

Common Austrian IBAN Mistakes

Confusing Austrian and German BLZ

Both countries call their routing code "Bankleitzahl," but they are different systems with different lengths: Austria uses 5 digits, Germany uses 8 digits. An Austrian BLZ embedded in a German IBAN template will produce an IBAN with the wrong structure and invalid check digits.

Missing Zero-Padding on the Account Number

Austrian account numbers must be exactly 11 digits in the IBAN. Older account numbers of 8 or 9 digits must be left-padded with zeros. Skipping this step produces a 17- or 18-character IBAN that fails the length check.

Spaces in Electronic Transmission

Remove all spaces: AT232011100234573201.

Austrian IBAN and SEPA

Austria is a founding SEPA member and eurozone country. All Austrian bank accounts support SEPA Credit Transfers and Direct Debits. For payments outside SEPA, including to Switzerland, which borders Austria, you need the bank's BIC. Look up any Austrian bank's BIC using the ibanchecker.cash SWIFT directory.

Validating Austrian IBANs in Bulk

Finance teams processing DACH-region payments can validate Austrian IBANs alongside German ones using the ibanchecker.cash bulk checker. Upload a CSV with up to 100 IBANs and receive per-row results with Bankleitzahl, bank name, and any errors.

Sources & References

• SWIFT IBAN Registry — Official IBAN country format specifications
• ISO 13616 — International standard for IBAN
• EPC SEPA Participants — SEPA scheme participants register
• Oesterreichische Nationalbank (OeNB) — Austrian central bank and authority for BLZ assignments
• ECB TARGET2 — Eurozone payment system operated by the European Central Bank

Last updated: June 2026