Checking a customer's VAT number before you zero-rate

Zero-rating an EU business rests on their VAT number being real. If it is not, the VAT does not disappear - it becomes yours.

Last reviewed 21 September 2026

There is a specific moment this page is about. A new customer in another Member State sends you their VAT number, you put it on the invoice, you charge no VAT, and you move on. Everything rests on that number being real, and checking takes about twenty seconds.

What VIES is

The VAT Information Exchange System lets traders confirm the VAT registration numbers of customers in other EU Member States. It is run by the European Commission, it is free, and it needs no account. You choose the Member State, enter the number, and it tells you whether that number is valid for intra-EU trade.

Why the check is not optional in practice

Zero-rating a cross-border supply to a business is not a courtesy you extend — it is a treatment that depends on conditions being met, and the customer being registered for intra-EU trade is one of them. If the number does not validate, the basis for charging no VAT is missing.

The consequence is asymmetric, which is what makes it worth twenty seconds. Your customer has paid the invoice and gone. The VAT that should have been accounted for does not evaporate; it lands on you, out of a margin that was priced without it. This is the same shape as registering late — the cost arrives long after the decision, and the customer is not there to share it.

What a valid result does and does not tell you

• It does tell you the number is registered and valid for intra-EU trade at the moment you check.
• It does not tell you that the person who gave it to you is entitled to use it.
• It does not tell you that the trade is what it appears to be.
• It is a point in time. A number valid in March can be cancelled by September.

So: check at the start of the relationship, check again if a long time passes or the pattern of orders changes, and keep a record of when you checked and what it said. The record is the part people skip and the part that matters if anyone asks later.

The statement you owe afterwards

Zero-rating an EU business is not the end of it. An Irish VAT-registered trader who zero-rates goods, services or both to a VAT-registered trader in another Member State must submit a VIES statement — and Revenue is explicit that this applies regardless of the value of the supply. There is no small-amount exemption.

Two details that catch people:

• Statements are filed online through ROS, monthly or quarterly.
• Where you made no such supplies in a period, a nil statement is still required. Silence is not a filing.

If your own number will not validate

An Irish number that fails a VIES check is usually not broken — it is domestic-only rather than intra-EU. Domestic-only registrations are deliberately not on VIES, which is the whole point of the two-tier system. The fix is an application to move tier, not a phone call about a fault.

Where this meets the invoice

The number is not just a note in your records. On an intra-Community supply of goods the invoice must carry the customer’s VAT number and the notation that it is an intra-Community supply; on a reverse-charge supply it must carry the number and the words reverse charge applies. The invoice requirements guide has the full list, and the reverse-charge guide has the wording.