Austrian VAT Number Check

About the Austrian VAT number

In Austria the VAT identification number is called the Umsatzsteuer-Identifikationsnummer, almost always shortened to UID or UID-Nummer. It is issued by the Austrian tax office to businesses that take part in intra-EU trade.

The Austrian number is easy to recognise: after the AT country code it always continues with the letter U, then eight digits. The U is part of the number itself, not a separator, so every valid Austrian VAT number begins with the same three characters: ATU.

Austrian VAT number format

• Format: ATU + 8 digits
• Example: ATU12345678 (illustrative, not a real number)
• Length: 11 characters including the prefix
• Local name: Umsatzsteuer-Identifikationsnummer, UID-Nummer
• The full number is ATU followed by 8 digits, for example ATU12345678. The last digit is a check digit.
• Dropping the U (AT12345678) is the most common Austrian format error and always fails.

Where to find a Austrian VAT number

• On invoices issued by the Austrian business: the supplier UID is a standard invoice detail.
• In the imprint (Impressum) of the company website, where many Austrian businesses list their UID.
• In correspondence and order confirmations, usually next to the company register number (Firmenbuchnummer).

Common input mistakes

• Leaving out the U after AT.
• Entering the tax number (Steuernummer) used for domestic filings, which is a different identifier.
• Entering the company register number (Firmenbuchnummer, for example FN 123456a) instead of the UID.

Austrian VAT numbers in practice

Austrian businesses can confirm a UID themselves in FinanzOnline, the online portal of the Austrian Federal Ministry of Finance. Its UID confirmation procedure has two levels: level 1 answers only whether a number is valid, while level 2 also confirms the name and address of the holder. VIES gives the same kind of valid or invalid answer for numbers from every member state, which is why it is the usual first check when a customer list mixes several countries.

Austrian invoice rules make the customer UID matter even at home: on an invoice from an Austrian business to another business with a total above EUR 10,000 including VAT, the UID of the customer must also be shown. Small businesses that use the Austrian small-business exemption (Kleinunternehmerregelung) do not charge VAT and do not always have a UID.

How to check Austrian VAT numbers

Paste your Austrian numbers into the validator above, one per line, each starting with AT. Spaces, dots and hyphens are removed automatically, and lower-case letters are converted to upper case.

justaxit first checks each entry against the Austria format (ATU + 8 digits). Numbers with the wrong shape are flagged immediately and are not sent to VIES. Well-formed numbers are then checked through VIES, which asks the Austria tax administration whether the number is currently valid for intra-EU transactions.

Each result shows valid or invalid, plus the name and address when the member state shares them through VIES. If the national service is temporarily unavailable, the number is marked for retry rather than reported as invalid. Registered users can save lists and export results to CSV, Excel or PDF.

Austrian VAT number FAQ

What does an Austrian VAT number look like?

ATU followed by 8 digits, for example ATU12345678. That is 11 characters in total including the ATU prefix.

Why does my Austrian UID fail the format check?

Most often the U is missing (AT12345678) or a digit was dropped. The number must be exactly ATU plus 8 digits.

Is the UID the same as the Austrian tax number (Steuernummer)?

No. The Steuernummer is used for domestic tax matters and is not in VIES. For intra-EU trade you need the UID that starts with ATU.

Can I check many Austrian UID numbers at once?

Yes. Paste them one per line into the validator on this page or the batch EU VAT checker; every number is format-checked and then queried through VIES.