EU VAT Number Format

As of the writing of this web page, the following are the known formatting rules for EU VAT numbers. If you want to check whether your VAT number is valid, you may try the VAT Number Validation web page operated by EU.
EU Country Abbreviation VAT Number Format National Prefix Example Notes
Austria MWST One letter and eight digits AT AT U12345678 The first character is always 'U'
Belgium BYW Nine digits BE BE 123456789  
Denmark MOMS Eight digits DK DK 12345678  
Finland ALV Eight digits FI FI 12345678  
France TVA Eleven digits

or

Ten digits and one letter

or

Nine digits and two letters
FR FR 12345678901

or

FR X2345678901

or

FR 1X345678901

or

FR XX345678901
May include 1 or 2 letters :-

Either FIRST, SECOND or FIRST & SECOND.

All letters except O and I are valid.
Germany MWST Nine digits DE DE 123456789 Must be the 9 digit 'Umsatzsteur Identifikationnummer' (Ust ID Nr.)
Greece ΦΠΑ Nine digits EL EL 012345678 Prefix any 8 digit number with zero
Ireland VAT Seven digits and one letter

or

Six digits and two letters
IE IE 1234567X

or

IE 1X34567X
Includes 1 or 2 letters :-

Either LAST or SECOND & LAST
Italy IVA Eleven digits IT IT 12345678901  
Luxembourg TVA Eight digits LU LU 12345678  
Netherlands BTW Eleven digits and one letter NL NL 123456789B01 Tenth character is always 'B'

The 3 digit suffix is always B01 to B99.
Portugal IVA Nine digits PT PT 123456789  
Spain IVA Eight digits and one letter

or

Seven digits and two letters
ES ES X12345678

or

ES 12345678X

or

ES X1234567X
Includes 1 or 2 letters :-

Either FIRST, LAST or FIRST & LAST.
Sweden MOMS Twelve digits SE SE 123456789001 The last 2 characters must be '01'.
UK VAT Nine digits

or

Twelve digits
GB GB 123456789

or

GB 123456789001
Twelve digits if the number represents a sub-company within a group