BTW/Ondernemingsnummer:

VAT identification number structure
Member StateStructureFormat*
AT-AustriaATU999999991 block of 9 characters
BE-BelgiumBE09999999991 block of 10 digits
BG-BulgariaBG999999999 or BG99999999991 block of 9 digits or1 block of 10 digits
CY-CyprusCY99999999L1 block of 9 characters
CZ-Czech RepublicCZ99999999 or CZ999999999 or CZ99999999991 block of either 8, 9 or 10 digits
DE-GermanyDE9999999991 block of 9 digits
DK-DenmarkDK99 99 99 994 blocks of 2 digits
EE-EstoniaEE9999999991 block of 9 digits
EL-GreeceEL9999999991 block of 9 digits
ES-SpainESX9999999X41 block of 9 characters
FI-FinlandFI999999991 block of 8 digits
FR-France FRXX 9999999991 block of 2 characters, 1 block of 9 digits
GB-United KingdomGB999 9999 99 or GB999 9999 99 9995 or GBGD9996 or GBHA99971 block of 3 digits, 1 block of 4 digits and 1 block of 2 digits; or the above followed by a block of 3 digits; or 1 block of 5 characters
HR-CroatiaHR999999999991 block of 11 digits
HU-HungaryHU999999991 block of 8 digits
IE-IrelandIE9S99999L or IE9999999WI1 block of 8 characters or 1 block of 9 characters
IT-ItalyIT999999999991 block of 11 digits
LT-LithuaniaLT999999999 or LT9999999999991 block of 9 digits, or 1 block of 12 digits
LU-LuxembourgLU999999991 block of 8 digits
LV-LatviaLV999999999991 block of 11 digits
MT-MaltaMT999999991 block of 8 digits
NL-The NetherlandsNL999999999B9981 block of 12 characters
PL-PolandPL99999999991 block of 10 digits
PT-PortugalPT9999999991 block of 9 digits
RO-RomaniaRO9999999991 block of minimum 2 digits and maximum 10 digits
SE-SwedenSE9999999999991 block of 12 digits
SI-SloveniaSI999999991 block of 8 digits
SK-SlovakiaSK99999999991 block of 10 digits

Remarks:

  • *: Format excludes 2 letter alpha prefix
  • 9: A digit
  • X: A letter or a digit
  • S: A letter; a digit; "+" or "*"
  • L: A letter

Notes:

  • 1: The 1st position following the prefix is always "U".
  • 2: The first digit following the prefix is always zero ('0').
  • 3: The (new) 10-digit format is the result of adding a leading zero to the (old) 9-digit format.
  • 4: The first and last characters may be alpha or numeric; but they may not both be numeric.
  • 5: Identifies branch traders.
  • 6: Identifies Government Departments.
  • 7: Identifies Health Authorities.
  • 8: The 10th position following the prefix is always "B".
  • 9: All letters are case sensitive. Please follow the exact syntax of the VAT number shown.

Source: http://ec.europa.eu/taxation_customs/vies/faq.html