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VAT number checker: UK numbers with HMRC, EU numbers with VIES

Check that a customer's or supplier's VAT number exists before you invoice them. UK numbers are checked against HMRC, EU numbers (and Northern Ireland XI numbers) in VIES, the European Commission's system.

UK: GB + 9 digits (12 for some branch or group numbers); the GB prefix is added if you leave it out. Northern Ireland XI numbers and EU numbers: type the country code first.

Enter a VAT number, then click Check.

Source: VIES, the European Commission's VAT number check

How the check works

A UK VAT registration number is 'GB' followed by 9 digits, or 12 digits for some branch or group registrations. The tool first checks this format. HMRC does not publish the check-digit rule in the sources we read, so only the format is checked locally.

The number is then checked with HMRC's 'Check a UK VAT number' service, which confirms whether the number is valid and returns the registered name and address. VIES, the European Commission's system, no longer covers GB numbers.

Businesses in Northern Ireland that sell or move goods between Northern Ireland and the EU use the prefix XI: those numbers are checked in VIES, like the numbers of EU countries. For an EU number, type it with its country code (IE, FR, DE…).

Only HMRC or VIES can say whether a number is active. A correct format is not proof of registration.

  • A full VAT invoice shows your own VAT number; your customer's VAT number is not required on UK domestic invoices (VAT Notice 700/21).
  • Nothing you type is stored by Le Frac.

Official sources

Rules checked on 20 October 2026. Free tool for information only: it is not legal or tax advice. The rules are checked against the official sources listed on this page; check your own situation before acting.

Frequently asked questions

What does a UK VAT number look like?

GB followed by 9 digits, for example GB 123 4567 89. Some branch or group registrations have 12 digits. Businesses in Northern Ireland trading goods with the EU use XI instead of GB.

Why are GB numbers not checked in VIES?

VIES only covers EU VAT numbers and, for Northern Ireland goods trade, XI numbers. GB numbers are checked with HMRC.

The format is correct but the number is not recognised: why?

The business may not be registered, may have been deregistered, or the number may contain a typing error. Ask your customer to confirm the number.

Do I need my customer's VAT number on my invoice?

Not for a sale within the UK: a full VAT invoice shows your VAT number and your customer's name and address. Special rules apply to some cross-border sales.

Further reading

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