VAT Number Format Rules

Core structure

An EU VAT identification number consists of a two‑letter country prefix followed by a national identifier. The national part can include digits and, in some countries, letters. Length and character rules vary by member state.

Common formatting mistakes

• Omitting the country prefix.
• Using spaces or punctuation copied from documents (VIES expects a clean value).
• Mixing domestic tax numbers with the VAT identification number used for intra‑EU trade.
• Using the wrong country prefix for the entity’s establishment.

Why formats differ

VAT IDs are issued by national tax authorities. VIES provides a unified validation front-end, but each member state applies its own format and validity rules behind the scenes.

Practical validation approach

• Validate the prefix and basic length locally (to catch obvious input errors).
• Use VIES for definitive validity status at query time.
• Store the normalized VAT ID in your system to avoid repeated formatting errors.

Related pages

VAT verification overview | VAT formats by country | When to use VAT vs EORI vs LEI