An unverified Austrian VAT (Value Added Tax) number costs you the zero rate, blocks your input tax deductions, and gets your invoices rejected. Cross-border finance teams carry this risk on every intra-EU sale, and a single wrong digit is enough to trigger it.
You verify an Austrian number two ways. Anyone can check it free in the European Commission’s VIES (VAT Information Exchange System) public lookup. Austrian registered businesses can run a documented confirmation inside FinanzOnline, Austria’s official tax portal. Both are covered in full below.
How Do You Verify an Austrian VAT Number?
Verify an Austrian VAT number two ways. Enter the ATU number in VIES for a free public check anyone can run, with no login. If you are an Austrian registered business, run a Stufe 2 confirmation in FinanzOnline for documented proof that the number belongs to a specific name and address. This is the verdict; everything below is depth.
| Tool | Who can use it | What it proves | Cost |
|---|---|---|---|
| VIES (European Commission) | Anyone, no login | Number is valid for intra-EU trade; issues a consultation number as proof | Free |
| FinanzOnline UID-Bestätigungsverfahren | Austrian registered businesses (login) | Stufe 1 validity, or Stufe 2 name-and-address match | Free |
Source: European Commission VIES FAQ and Austria’s business portal usp.gv.at.
What Is a UID Number, and How Is It Different From an Austrian Tax Number?
The UID (Umsatzsteuer-Identifikationsnummer) is Austria’s EU VAT identification number for intra-EU trade. The Steuernummer is the domestic tax number used for all tax matters. They are different identifiers with different formats. Only the UID is checkable in VIES; entering a Steuernummer returns “no record found.”
| Identifier | German name | Format | Purpose | Who issues it |
|---|---|---|---|---|
| VAT ID | Umsatzsteuer-Identifikationsnummer (UID) | ATU + 8 digits (e.g. ATU12345678) | Intra-EU trade | Federal Ministry of Finance (BMF) via the Finanzamt, per usp.gv.at |
| Tax number | Steuernummer | 9 digits, 2-digit office code + 7 digits (e.g. 11-999/9118) | Domestic tax administration | The Finanzamt, per usp.gv.at and bmf.gv.at |
The usp.gv.at guidance confirms the UID is issued automatically (“von Amts wegen”) with the Steuernummer, or on request via form U15.
What Is the ATU Number Format?
The Austrian VAT number is the country code AT, plus a fixed letter U (for Umsatzsteuer), plus 8 digits, for example ATU12345678. That is 11 characters in total. Austria is unusual in the EU for embedding a fixed letter inside the number. The final digit is a check digit, which is why typos fail validation instantly.
| Element | Value | Notes | Source |
|---|---|---|---|
| Country code | AT | Austria’s ISO country prefix | BMF UID construction rules |
| Fixed letter | U | Stands for Umsatzsteuer; position C1, always alphabetic | BMF UID construction rules |
| Digits | 8 numeric (C2–C9) | Positions C2 to C9 | BMF UID construction rules |
| Check digit | C9 (last digit) | Weighted modulo-10 checksum over the preceding digits | BMF UID construction rules |
| Total length | 11 characters | AT + U + 8 digits | EUIPO EU VAT numbers table |
The check-digit formula is published by the BMF in its UID construction rules (PDF, Stand November 2020). The BMF’s UID query webservice rejects any number that does not start with ATU with return code 101, per its webservice specification.
Which Typos Make an Austrian VAT Number Fail Validation?
Because the last digit is a checksum, most typos break the check digit and fail on entry. The frequent ones:
- Missing a digit: writing ATU1234578 (7 digits) instead of ATU12345678.
- Missing the U: writing AT12345678, which the BMF service rejects outright.
- Extra characters: adding stray letters or symbols after the number.
- Wrong spacing: inserting spaces like ATU 1234 5678, which automated systems reject.
- Steuernummer instead of UID: a very common cross-border mix-up that returns “no record.”
Who Needs a UID Number in Austria?
Any business making intra-EU supplies or acquisitions needs a UID. So does one receiving cross-border B2B services under reverse charge, or one exceeding the domestic turnover threshold. Exempt small businesses (Kleinunternehmer) can still request a UID for EU trade. The registration triggers and current thresholds are below.
| Trigger | Detail | Source |
|---|---|---|
| Intra-EU supplies or acquisitions | UID required to trade goods or services across EU borders | usp.gv.at |
| Cross-border B2B services (reverse charge) | UID needed to establish business status | usp.gv.at |
| Domestic turnover above the Kleinunternehmer limit | €55,000 gross, effective 1 Jan 2025 (up from €35,000 net through 31 Dec 2024) | usp.gv.at |
| 10% tolerance band | Exemption held for the calendar year up to €60,500 | usp.gv.at |
| Intra-EU acquisitions above the Erwerbsschwelle | €11,000 per calendar year | usp.gv.at |
| Exempt small business needing a UID for EU trade | Request via form U15 or FinanzOnline | usp.gv.at |
The €55,000 gross threshold and 10% tolerance rule are confirmed on the usp.gv.at Kleinunternehmen page.
Why Verify a VAT Number Before Invoicing?
Since 1 January 2020, the EU Quick Fixes made a valid customer VAT number a substantive condition of the Article 138 zero rate, not a formality. An invalid number can make the supplier liable for the VAT. Verification also decides B2B reverse-charge status and protects your input-tax deduction on purchases.
The customer’s VAT number and a correct recapitulative statement are both required for the exemption, per the EU Commission explanatory notes on the 2020 Quick Fixes (PDF). Verifying before you invoice is what turns a claimed zero rate into a defensible one. A rejected number found after the sale leaves you owing tax you never collected.
How Do You Check an Austrian VAT Number in VIES?
Check an Austrian number in VIES in four steps. VIES is run by the European Commission and queries Austria’s national database live at the moment of the request. Enter your own VAT number alongside the target to receive a consultation number, the dated request ID every EU tax administration accepts as proof you verified the partner.
- Open the European Commission’s VIES tool.
- Select Austria (AT) and enter the ATU number in full.
- Enter your own VAT number in the requester fields to generate a consultation number.
- Read the result: valid or invalid, with the registered name and address where returned.
Austria may return a null name and address in VIES; member states can withhold that data for privacy reasons, per the VIES FAQ. A missing name does not mean the number is invalid. Keep the consultation number as your dated, audit-ready record of the check.
How Does the FinanzOnline UID Confirmation Work?
FinanzOnline is Austria’s tax portal for registered taxpayers, not a public lookup. Its UID-Bestätigungsverfahren runs in two stages. Stufe 1 confirms validity only. Stufe 2 confirms the number belongs to a specific name and address, and is the standard for new trading partners. A confirmed number counts as valid for the whole query day.
A Stufe 2 query returns the counterparty’s name plus 6 address lines, delivered the next day to the requester’s FinanzOnline Databox, per the BMF UID webservice specification (PDF). The printed confirmation is a record to retain under § 132 of the Bundesabgabenordnung (BAO), Austria’s federal fiscal code.
| Feature | VIES | FinanzOnline UID-Bestätigungsverfahren |
|---|---|---|
| Access | Public, anyone | Austrian registered taxpayers |
| Login | None | FinanzOnline login required |
| Proof issued | Consultation number (dated request ID) | Stufe 2 confirmation to the Databox, retained under § 132 BAO |
| Name/address matching | Austria may return null | Stufe 2 returns name + 6 address lines |
| Best for | Quick free public checks | New trading partners, audit-ready proof |
What If a Valid VAT Number Shows as Invalid?
An “invalid” or “unavailable” VIES result often means the national database is down or a newly issued UID has not synced yet, not that the number is bad. VIES queries Austria’s system live, so a temporary outage reads as unavailable. Work through the causes below before telling a partner their number is wrong.
| Result | Likely cause | Fix |
|---|---|---|
| Invalid | Typo or failed check digit | Recheck the ATU format and re-enter |
| Invalid but partner says registered | New UID not yet synced to VIES | Retry later; ask the partner to confirm with their Finanzamt |
| Service unavailable | National database temporarily down | Retry later and document the attempt |
| No record found | Steuernummer entered instead of UID, or number deregistered | Confirm you have the ATU number; request a Stufe 2 confirmation |
What Are the Consequences of Using an Invalid VAT ID?
Using an invalid VAT number costs you the zero rate, so the supplier owes the VAT that was never charged. It also gets input-tax deductions denied, invoices rejected, and raises audit exposure. Trading partners running due diligence may reject you outright. The Quick Fixes liability is the sharpest of these risks.
Because a valid customer VAT number is a substantive condition of the Article 138 exemption since 1 January 2020, per the EU Commission explanatory notes, an unverified number shifts the VAT bill back onto the supplier. Denied deductions and rejected invoices then compound the cost, and repeated errors invite closer scrutiny at audit.
How Do You Verify VAT Numbers in Bulk?
VIES offers a SOAP and REST API for automated checks, and businesses with many suppliers build validation into onboarding and invoicing rather than checking numbers one by one. This keeps every supplier record current before an invoice ever goes out. Commenda automates this at scale with VAT ID validation, CSV upload, and API access.
Commenda supports 100+ ERP, API, and custom integrations, so validation slots into the systems you already run, listed on the Commenda integrations page. Its Global Tax ID Verification tool checks tax IDs across countries, which fits supplier onboarding and cross-border invoicing directly.
How Commenda Helps With Austrian VAT Compliance
Commenda gives finance teams certainty that every Austrian VAT number is checked before it hits an invoice. Commenda’s global indirect tax software automates VAT ID validation across EU jurisdictions, handles filings, and keeps audit-ready records so nothing depends on remembering to run a manual check.
Pair it with the Global Tax ID Verification tool to confirm numbers at onboarding, and the compliance calendar to track Austrian and EU filing deadlines by entity. Book a demo to see every supplier VAT number validated automatically before your next intra-EU invoice goes out.
