How to check an Irish VAT number

How to validate an Irish or EU VAT number through VIES, what the Irish number format looks like, and why the check protects you rather than your customer.

Updated 11 September 20265 min readWritten by Finlay Mulligan & Co.

The short answer

Irish and other EU VAT numbers are validated free through the European Commission's VIES service. An Irish VAT number is the letters IE followed by seven digits and one or two letters. If you zero-rate a supply to an EU business customer, keep dated evidence of the VIES check — without it, the VAT is yours to pay.

The Irish VAT number format

An Irish VAT number starts with the country code IE. What follows is one of two historic patterns, both of which are still in use and both of which are valid.

PatternShapeExample shape
Older formatSeven digits and one letterIE1234567A
Newer formatSeven digits and two lettersIE1234567AB
Legacy formatDigit, character, five digits, letterIE1A23456B

The character in the second position of the legacy format may be a letter, a digit, the plus sign or an asterisk. If a supplier gives you a number in that shape, it is not necessarily wrong — it is old.

Format alone proves nothing. A number can be perfectly shaped and still be cancelled, never issued, or belong to an entirely different business. Only the VIES check tells you whether it is live today.

Checking a number through VIES

VIES is the European Commission's VAT Information Exchange System. It queries each member state's own register in real time, and it is free.

  1. Open the VIES validation page on the European Commission website.
  2. Select the member state — IE for Ireland — and enter the number without the country prefix.
  3. Enter your own VAT number in the requester field. Doing so produces a consultation number.
  4. Record the consultation number, the date and the result. This is the part most businesses skip and the part that matters.

Why the check protects you

When you supply goods or services to a VAT-registered business in another EU member state, you can generally zero-rate the supply and the customer accounts for the VAT under the reverse charge. That treatment depends on the customer actually being registered for intra-EU trade.

If the number turns out to be invalid, Revenue's position is straightforward: the conditions for zero-rating were not met, so Irish VAT was due on that sale. The assessment comes to you, not to your customer, and it comes with interest. On a decent-sized export invoice that is a material sum recovered from your own margin.

  • Check the number before you zero-rate the first invoice, not at year end.
  • Re-check periodically for recurring customers. Registrations get cancelled.
  • Keep the consultation number, the date and a screenshot with the customer file.
  • Make sure the name VIES returns matches the customer you are actually invoicing.

When VIES says the number is invalid

An invalid result is not always fraud. The common causes are mundane, and worth working through before you assume the worst.

  • The customer holds a domestic-only registration and is not authorised for intra-EU trade. This is very common in Ireland.
  • The number was transcribed with a transposed digit or a missing trailing letter.
  • The registration has been cancelled because the business ceased or was deregistered.
  • The relevant member state's database was temporarily unavailable, which VIES reports distinctly from an invalid number.

Until the customer produces a number that validates, the correct treatment is to charge Irish VAT. You can credit and reissue once a valid number is confirmed. Zero-rating on a promise is the expensive option.

Finding a VAT number you do not have

There is no public directory that lets you look up a business and retrieve its VAT number. VIES confirms a number you already hold; it does not search by company name. If you need a customer's number, ask them for it in writing, and take it from an invoice or a signed document rather than from an email footer.

For Irish companies, the Companies Registration Office register will confirm the legal entity, its registered address and its officers, which is a useful cross-check that the business you are dealing with exists and that the VIES name matches it.

Common questions

What does an Irish VAT number look like?
It begins with IE and is followed by seven digits and one or two letters, for example IE1234567A or IE1234567AB. An older legacy format places a letter, digit, plus sign or asterisk in the second position.
How do I check if an Irish VAT number is valid?
Use the European Commission's VIES service. Select Ireland, enter the number without the IE prefix, and enter your own VAT number so that the system returns a consultation number you can keep as evidence.
Is checking a VAT number free?
Yes. VIES validation is provided free by the European Commission and there is no limit on ordinary business use.
What happens if I zero-rate a sale to an invalid VAT number?
The conditions for zero-rating are not met, so Irish VAT is treated as due on that supply. Revenue assesses it against you as the supplier, with interest, and recovering it from the customer afterwards is usually impractical.
Why does VIES say my Irish customer's number is invalid when they are registered?
Most often because they hold a domestic-only Irish VAT registration rather than an intra-EU one. A domestic-only number is valid in Ireland but does not appear on VIES.

Sources

Figures in this guide are taken from the following official sources and were correct on 11 September 2026.

This guide is general information about Irish tax and company law, not advice on your own affairs. Rules change and individual circumstances differ. Talk to us before you act on anything here.

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