What is a VAT number? EU and UK formats, how to check one, and who needs one

The law behind it is the VAT Directive, Directive 2006/112/ECDirective 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)The whole regulationClick opens the law on the EU Publications Office.. Every EU country must give an individual number to each taxable person that makes taxable supplies of goods or services in its territory, and to each business that buys goods from another EU country subject to VAT (Art. 214(1)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 214, paragraph 1Click opens the article on EUR-Lex.). A taxable person is anyone who independently carries out an economic activity, whatever its purpose or result (Art. 9(1)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 9, paragraph 1Click opens the article on EUR-Lex.). Every number carries the prefix of the country that issued it, from ISO 3166 alpha-2; Greece may use EL, and XI is used for Northern Ireland (Art. 215Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 215Click opens the article on EUR-Lex.).

VAT itself is a tax on consumption, charged on each sale along the chain. Each business charges VAT on its price and deducts the VAT it paid on its own costs (Art. 1(2)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 1, paragraph 2Click opens the article on EUR-Lex., Art. 168Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 168Click opens the article on EUR-Lex.).

Two rules make the warehouse rows apply from the first sale. The EUR 10,000 threshold is only for a supplier established in one EU country (Art. 59c(1)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 59c, paragraph 1Click opens the article on EUR-Lex.), and the VAT exemption for small enterprises is only for businesses established in the EU (Art. 284Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 284Click opens the article on EUR-Lex.). A business outside the EU gets neither.

One rule runs the other way. Where a supplier not established in a country sells there, that country may make the customer pay the VAT instead (Art. 194Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 194Click opens the article on EUR-Lex.), and a sale taxed that way does not by itself call for a VAT number there (Art. 214(1)(a)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 214, paragraph 1, point (a)Click opens the article on EUR-Lex.). Whether a country does this, and for which customers, is its own choice.

OSS needs the VAT number first. The Commission states that a business not established in the EU “will be allocated a VAT number by the Member State of identification before registering for the scheme” (Commission, Register to OSS). How the VAT on each of these sales works is on EU VAT for online sellers.

The Commission does not publish the algorithms behind these numbers: “The European Commission cannot divulge these algorithms.” A number that fits its shape can still be invalid, so the shape is a first test, not a check. Austrian numbers are entered in VIES with the U: “You should therefore enter a ‘U’ as the first character when verifying an Austrian VAT identification number.”

When a number comes back invalid. The Commission’s steps: check the number with your customer first, for the right characters, length and prefix. If it still fails, the customer asks its own tax administration to update the VIES data; only national tax administrations can change it. A correct number can fail for one more reason: “Some Member States / Northern Ireland require an additional registration for intra-EU transactions and record in their national VIES databases only such VAT numbers.” If your own number shows as invalid, it is the tax administration that issued it that corrects it.

Each answer is live. VIES asks the issuing country’s database at the moment you check, and a country’s database can be down for maintenance. Where you believe the customer is not a business, the Commission’s answer is to charge VAT: “you should not exempt the supply but should charge VAT.”

The check matters most on a sale of goods to a business in another EU country. That sale is exempt only where the buyer is VAT-registered in another EU country and has given you its number (Art. 138(1)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 138, paragraph 1Click opens the article on EUR-Lex.), and only where you list the sale in your recapitulative statement, the EC Sales List (Art. 138(1a)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 138, paragraph 1aClick opens the article on EUR-Lex.). A business customer must give its VAT number to its suppliers for those sales (Implementing Reg. Art. 55Implementing Regulation (EU) No 282/2011, VAT implementing measures (consolidated text of 14 April 2025)Article 55Click opens the article on EUR-Lex.). For services, a supplier may treat an EU customer as a business where the customer gives its VAT number and the supplier confirms it, VIES being the Commission’s way to do that (Implementing Reg. Art. 18(1)Implementing Regulation (EU) No 282/2011, VAT implementing measures (consolidated text of 14 April 2025)Article 18, paragraph 1Click opens the article on EUR-Lex.).

Selling through a marketplace, HMRC also expects you to register as an overseas seller where the marketplace gives you the VAT details of a business customer, or where you sell goods located in Northern Ireland to customers there. Once registered, give your number to every marketplace you sell on in the UK, under the same business name you registered with: HMRC states that a marketplace “may remove you” if it cannot match your trading name to the name on the UK VAT number checker. An overseas seller that does not meet the rules can be directed to appoint a UK VAT representative or to give security, besides the normal penalties. Register late and “you must pay VAT on any sales you’ve made since the date you should have registered.”

VAT, EORI, IOSS and tax ID numbers are four different numbers

Is a VAT number the same as an EORI number or a tax ID? No. Each does its own job, and a form that asks for one will not take another.

The EORI number is “an identification number, unique in the customs territory of the Union, assigned by a customs authority” (Art. 1(18) of Delegated Regulation (EU) 2015/2446); the EORI number guide covers who needs one. EU law keeps the TIN and the VAT number apart too: for a seller resident in the EU, a platform reporting under DAC7 collects the TIN and, “where available”, the VAT identification number, as two items (Directive (EU) 2021/514, Annex V, Section II, paragraph B). The intermediary that files IOSS for you gets its own IN number, which “is not a VAT identification number” (Commission, Register to OSS).

Where your VAT number goes once you have one

• On every invoice you must issue. The invoice shows your VAT number; on an exempt sale to a business in another EU country, or one where the customer pays the VAT, it shows the customer’s number too (Art. 226Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 226Click opens the article on EUR-Lex., points (3) and (4)). An invoice is required for every sale to a business, and for a sale to a consumer shipped between EU countries unless you declare it through OSS (Art. 220(1)Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 220, paragraph 1Click opens the article on EUR-Lex.).
• In a marketplace’s records. A marketplace keeps records of the sales it facilitates, for 10 years (Art. 242aDirective 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 242aClick opens the article on EUR-Lex.). For a sale it facilitates without being the deemed supplier, those records hold your VAT number where you have one (Implementing Reg. Art. 54c(2)Implementing Regulation (EU) No 282/2011, VAT implementing measures (consolidated text of 14 April 2025)Article 54c, paragraph 2Click opens the article on EUR-Lex.).
• In your OSS registration. OSS runs on the VAT number of your country of identification, and the registration also lists the VAT numbers you hold in other EU countries your goods ship from (Commission, Register to OSS).

What happens if you sell without one when you need one

The VAT is due whether or not you registered: it is payable by the business making the taxable sale (Art. 193Directive 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 193Click opens the article on EUR-Lex.). Without the number you cannot use OSS either, because OSS runs on it (Art. 369dDirective 2006/112/EC, the VAT Directive (consolidated text of 14 April 2025)Article 369dClick opens the article on EUR-Lex.), so each of those sales needs a VAT registration in the country of delivery instead. In the UK, a late registration means paying VAT on every sale since the date you should have registered, and you might pay a penalty.

What you can skip