Austria USt-IdNr. validator
How the USt-IdNr. format works
- Format
- AT U + 8 digits
- Example
- ATU12345678
Things to watch for
- Includes a literal U right after the country code
- This tool checks the format only; the Austrian check digit is not yet validated
^ATU[0-9]{8}$Austria’s UID (Umsatzsteuer-Identifikationsnummer) is the VAT number issued to Austrian businesses for cross-border EU trade, and it looks slightly different from most of its neighbors: “AT” is immediately followed by a literal letter “U”, then 8 digits — ATU12345678, never just 8 digits after “AT” alone. Any Austrian business invoicing another EU country, or listed in a VIES cross-border check, carries this number on every invoice.
That embedded “U” catches people who assume every EU VAT number is just a two-letter country code plus digits. Drop it, or mistake it for a stray character and delete it, and the number no longer matches the format Austria’s tax authority (Finanzamt) actually issues — a mistake worth catching before it reaches a supplier record or an invoice.
Checking the format
This tool checks for the literal “ATU” sequence right after the country position, then confirms exactly 8 digits follow — entirely client-side, with nothing sent to a server and no signup required. It’s a structural check: it confirms the number is the right shape, not that its check digit is mathematically valid, since Austria’s official check-digit rule isn’t wired in yet.
Beyond the format check
A pass here means the number is correctly formed — not that it’s a live registration. Use the EU’s VIES lookup or contact the Finanzamt directly to confirm a UID is currently active; a format pass alone shouldn’t be treated as proof a supplier is VAT-registered today.
Scope: this page covers UID format only, not Austrian VAT registration, thresholds, or return filing — none of which a browser-side check can determine. Catch a typo here first; confirm registration status through VIES or the Finanzamt.
Content last reviewed 2026-07-07.
USt-IdNr. FAQ
Why is there a U right after AT in an Austrian VAT number?
It's part of the fixed format: Austria's UID always reads 'ATU' followed by 8 digits, for example ATU12345678. The U isn't a typo or a check letter — every valid Austrian VAT number has it.
Does this tool verify the Austrian check digit?
No, not yet. It confirms the ATU prefix and the 8-digit count, which is a structural check — the official check-digit calculation isn't implemented here.
How do I know if an Austrian UID is actually active?
Query the EU's VIES lookup or ask the Austrian tax office (Finanzamt) directly — this validator only tells you the number is shaped correctly, not that it's a live registration.