Home / Tools / VAT Number Checker / Austria
Austrian VAT Number Checker
An Austrian VAT number is the UID-Nummer: ATU followed by eight digits. It is issued by the tax office once a business is registered for VAT, and it is the number you need before you can zero-rate a supply to an Austrian business customer.
Austrian businesses also have a Steuernummer for domestic filings. Only the UID is registered in VIES, so it is the only one this checker can confirm.
Checked live against VIES, the European Commission’s VAT Information Exchange System. Not affiliated with the European Commission or the Austria tax authority.
Austria VAT number format
- Local name
- UID (Umsatzsteuer-Identifikationsnummer)
- Structure
- ATU + 8 digits
- Format example
- ATU12345678Illustrative: right shape, not a registered business.
- Standard rate
- 20% · reduced 13%, 10%
ATU plus eight digits — eleven characters in all, with the U part of the number rather than a separator. The last digit is a check digit. Invoices often print it as ATU 12345678; spaces are stripped before the check.
How this Austria check works
- Format, in your browser. As you type, the number is compared with the Austria pattern (prefix, length and characters). This costs nothing and sends nothing: a number in the wrong shape is rejected on the spot and never reaches the registry.
- Registration, live. A well-formed number is then looked up in VIES, the European Commission’s VAT Information Exchange System, which says whether it is registered today and, where the register publishes them, the business name and address. Free checks are limited per visitor per hour so the registry is not scraped through this page.
- More checks, or from your code. A free account gives you an API key with 100 validations a month, the same answer as this page as JSON.
What usually goes wrong
Dropping the U
AT12345678 is not a valid Austrian VAT number in any system. The U is part of the identifier, so a number without it fails the format check before it reaches VIES.
Sending the Steuernummer
The Steuernummer identifies a business to its local tax office and is not in VIES. If a customer's number does not start with ATU, it is almost certainly the wrong one — ask for the UID-Nummer.
Frequently asked questions
What does the U in ATU stand for?
It is part of the Austrian identifier format: every Austrian UID-Nummer starts with U after the AT country code. Treat ATU as the prefix and expect exactly eight digits after it.
Where do I find an Austrian company's UID-Nummer?
Austrian invoices must show the supplier's UID, and business letters and websites usually carry it in the legal notice (Impressum). The commercial register number (FN) is a different number and will not validate.
Is checking the format enough?
No. A number in the right shape may never have been issued, or may have been cancelled. The format check catches typos instantly; the VIES lookup tells you whether the number is registered today.
Validating Austria numbers from your own code instead of by hand? The Austria VAT validation API guide has the endpoint, the response shape and examples in four languages. To check a number from another country, go back to the VAT number checker.