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Austria VAT number format

An Austria VAT identification number is the prefix AT followed by U + 8 digits; ATU13585627 is a well-formed example. The national check digit is public, so a mistyped number is caught before VIES is asked. Structure as published in the Commission’s VIES FAQ, consulted 2026-10-24.

Structure

Prefix AT, then U + 8 digits. The regular expression the API applies to the part after the prefix is ^U[0-9]{8}$; letters are upper-cased and spaces, dots and dashes removed before the test.

Country prefixStructureExamplePublic check digit
ATU + 8 digitsATU13585627yes, verified before VIES

The check digit

Austria publishes the algorithm of its check digit, so an impossible number is refused before VIES is asked: the answer says structure.checksum: "failed", costs nothing and reaches no upstream. The same algorithms are implemented by the open libraries (jsvat, python-stdnum).

How to validate it

The structure says whether a string can be an Austria VAT number; only VIES says whether it is registered. The free check below asks VIES live and shows the registered name and address where Austria publishes them; the API does the same from your code.

curl — validate ATU13585627 on VIES
curl "https://veriport.io/api/v1/vat/validate?number=ATU13585627"

What a valid answer proves

That the number was registered for intra-EU trade at the moment of the check. Keep the date and, on paid tiers, the VIES consultation number: together they are the evidence a tax audit asks for when an intra-EU supply was zero-rated.

Questions

How many digits does an Austria VAT number have?
U + 8 digits, after the two-letter prefix AT: ATU13585627 is an example.
Is ATU13585627 a real VAT number?
It is a well-formed example used in the documentation; whether it is registered today is VIES’s answer, not this page’s. Check it with the free tool.

Free: VIES asked live, the answer dated and sourced.

Check a VAT number

Sources