4.21. European VAT Numbers

Updated on June 7, 2022

Problem

As part of your job, you’ll be developing an online order form for a European Union corporation.

Your customer (a VAT-registered firm based in one EU country) shall not be charged VAT when purchasing from a vendor (your company) located in another EU country (Value-Added Tax). VAT must be charged and paid to the local tax office if the buyer is not VAT-registered. Sellers are required to provide the tax office with the buyer’s VAT registration information to prove that no VAT is due. When selling tax-exempt goods, the vendor must ensure that the customer has a valid VAT number in order to proceed.

Typographical errors by the consumer are the most frequent source of invalid VAT numbers. You should use a regular expression to validate the VAT number as soon as the consumer enters it into your online order form in order to speed up the process. Your web server’s CGI script or some JavaScript can be used to implement this functionality on the customer’s end. A typographical error can be immediately corrected by the customer if the number entered does not fit the regular expression.

Solution

This solution is divided into two sections in order to make it easier to apply. To begin, all white space and punctuation have been removed. Validation is the next step.

Strip whitespace and punctuation

The customer’s VAT number should be stored in a variable. Replace all matches of this regular expression with a blank replacement text before checking for a valid number:

[-.●]
There are no possibilities for regex in this case.
Regex flavors:.NET, Java, JavaScript, PCRE, Perl, Python, Ruby Recipe 3.14 explains you how to do this initial replacement. To avoid confusion, we’ve assumed that customers would only use hyphens, dots, and spaces when entering punctuation. The upcoming check will catch any more characters.

Validate the number

This regular expression, which removes all whitespace and punctuation, verifies that the VAT number is valid in all 27 EU countries:

^(
(AT)?U[0-9]{8} |                              # Austria
(BE)?0[0-9]{9} |                              # Belgium
(BG)?[0-9]{9,10} |                            # Bulgaria
(CY)?[0-9]{8}L |                              # Cyprus
(CZ)?[0-9]{8,10} |                            # Czech Republic
(DE)?[0-9]{9} |                               # Germany
(DK)?[0-9]{8} |                               # Denmark
(EE)?[0-9]{9} |                               # Estonia
(EL|GR)?[0-9]{9} |                            # Greece
(ES)?[0-9A-Z][0-9]{7}[0-9A-Z] |               # Spain
(FI)?[0-9]{8} |                               # Finland
(FR)?[0-9A-Z]{2}[0-9]{9} |                    # France
(GB)?([0-9]{9}([0-9]{3})?|[A-Z]{2}[0-9]{3}) | # United Kingdom
(HU)?[0-9]{8} |                               # Hungary
(IE)?[0-9]S[0-9]{5}L |                        # Ireland
(IT)?[0-9]{11} |                              # Italy
(LT)?([0-9]{9}|[0-9]{12}) |                   # Lithuania
(LU)?[0-9]{8} |                               # Luxembourg
(LV)?[0-9]{11} |                              # Latvia
(MT)?[0-9]{8} |                               # Malta
(NL)?[0-9]{9}B[0-9]{2} |                      # Netherlands
(PL)?[0-9]{10} |                              # Poland
(PT)?[0-9]{9} |                               # Portugal
(RO)?[0-9]{2,10} |                            # Romania
(SE)?[0-9]{12} |                              # Sweden
(SI)?[0-9]{8} |                               # Slovenia
(SK)?[0-9]{10}                                # Slovakia
)$

Regex options: Free-spacing, case insensitive

Regex flavors: .NET, Java, XRegExp, PCRE, Perl, Python, Ruby

The above regular expression uses free-spacing mode to make it easy to edit later. Every now and then, new countries join the European Union, and member countries change their rules for VAT numbers. Unfortunately, JavaScript does not support free-spacing. In this case, you’re stuck putting everything on one line:

^((AT)?U[0-9]{8}|(BE)?0[0-9]{9}|(BG)?[0-9]{9,10}|(CY)?[0-9]{8}L|↵
(CZ)?[0-9]{8,10}|(DE)?[0-9]{9}|(DK)?[0-9]{8}|(EE)?[0-9]{9}|↵
(EL|GR)?[0-9]{9}|(ES)?[0-9A-Z][0-9]{7}[0-9A-Z]|(FI)?[0-9]{8}|↵
(FR)?[0-9A-Z]{2}[0-9]{9}|(GB)?([0-9]{9}([0-9]{3})?|[A-Z]{2}[0-9]{3})|↵
(HU)?[0-9]{8}|(IE)?[0-9]S[0-9]{5}L|(IT)?[0-9]{11}|↵
(LT)?([0-9]{9}|[0-9]{12})|(LU)?[0-9]{8}|(LV)?[0-9]{11}|(MT)?[0-9]{8}|↵
(NL)?[0-9]{9}B[0-9]{2}|(PL)?[0-9]{10}|(PT)?[0-9]{9}|(RO)?[0-9]{2,10}|↵
(SE)?[0-9]{12}|(SI)?[0-9]{8}|(SK)?[0-9]{10})$

Regex options: Case insensitive

Regex flavors: .NET, Java, JavaScript, PCRE, Perl, Python, Ruby

Follow Recipe 3.6 to add this regular expression to your order form.