Originally published at . The point for this guide is that the buyer's VAT ID is central to that treatment, which is exactly why sellers care whether it is valid.
How a VAT ID is structured
At a glance, an EU VAT ID is:
[2-letter country prefix] + [up to ~12 alphanumeric characters]
For example, a German VAT ID looks like
DE123456789: theDEprefix, then the national portion. The national portion varies by country — some are all digits, some include letters, and lengths differ — so the "up to ~12 characters" is a rough envelope, not a single fixed pattern.
Two prefixes catch people out:
Greece usesEL, notGR. The VAT system usesELeven though the ISO country code isGR.
Northern Ireland usesXI. Under the Northern Ireland arrangements (Windsor Framework), NI VAT IDs for goods carry theXIprefix and are validatable through VIES.
Per-country patterns are worth a reference when you need them, but there is no reason to memorise 27 of them. The full breakdown is here: . Only a live check against VIES or a national source tells
you whether the number actually exists and is active — never infer registration from the shape of
the string alone.
For a single number, the fastest route is a .
When a business needs to validate other companies' VAT IDs
Checking one number by hand is fine. Checking VAT IDs on every signup, every invoice, or across an existing customer base is not — that is where you validate programmatically.
At that point you call a validation service from your own application: a when you need a specific national source. The other half of the job is keeping evidence: storing the result of each check — when it ran, what came back, and which source answered — so you can show your work later. Auditors on intra-EU supplies may ask for it; a lightweight record such as covers the request and response shape, and and validate against VIES from your own code.
FAQ
What is a VAT ID?
A VAT ID is the number a tax authority assigns to a business when it registers for value-added tax. It identifies that business for VAT purposes and is used on invoices and in intra-EU trade. Across the EU it takes the form of a two-letter country prefix followed by a country-specific string of characters.
Is a VAT ID the same as a VAT number?
Yes. "VAT ID", "VAT number", and "VAT registration number" all refer to the same identifier — the number that identifies a business for VAT. The different names are just wording; they point at the same value on your invoices and in VIES.
What is the difference between a VAT ID and a tax number?
A VAT ID identifies a business specifically for VAT and, in the EU, carries a country prefix so it works across borders. A local tax number (or company registration number) identifies the business to the domestic tax office or company register for other purposes. They are issued for different reasons and are usually different values, so they are not interchangeable on an intra-EU invoice.
How do I check if a VAT ID is valid?
For EU VAT IDs, validity is confirmed against VIES, the European Commission's system that routes the query to the relevant national database; some numbers are cross-checked against national registries. Note that a correct format is not the same thing as a registered, active number — only a live check confirms that. You can run a one-off check with a free VAT number checker.
Do I need a VAT ID to sell in the EU?
It depends on your situation — where you're established, what and to whom you sell, and whether you cross a registration threshold. Some businesses are required to register for VAT and some are not, and the rules differ by member state. This is not tax advice; check your national tax authority's guidance or a qualified advisor for your specific case.
What is the format of an EU VAT ID?
An EU VAT ID is a two-letter country prefix followed by up to roughly 12 alphanumeric characters, with the exact pattern set by each country. The prefix is the country code — for example Greece uses EL rather than GR, and Northern Ireland uses XI. A German VAT ID looks like DE123456789.
Check any EU VAT number free
Confirm a single VAT ID against VIES in seconds with the and call the VIES API from your own code — free plan, 100 requests/month.
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