Ireland VAT number validator

An Irish VAT number is the identifier Revenue issues to VAT-registered businesses trading in Ireland — shown as “IE” followed by 7 digits and one or two letters, for example IE1234567FA. Sole traders, companies, and freelancers who invoice above the VAT threshold, or who need a Revenue-valid number for intra-EU B2B trade, all need one, and it appears on every invoice and VIES check.

Getting a single character wrong matters more than it looks. An Irish VAT number with a transposed digit or a mistyped letter can still look plausible at a glance, but it will fail a customer’s VIES check or Revenue’s own systems — usually discovered only after an invoice has already gone out the door.

How this validator works

This tool checks the shape of an Irish VAT number entirely in your browser: the “IE” prefix, the 7-digit block, and the trailing letter or letters — Ireland has used both a single-letter and a two-letter suffix format depending on when the number was issued. It runs instantly, with no signup and nothing sent to a server.

What a pass doesn’t tell you

Ireland’s VAT number does have a documented check digit — a modulus-23 calculation run against the 7-digit block — but this validator doesn’t compute it yet. Right now it’s a structural check, not a checksum: confirming the “IE” prefix, digit count, and letter pattern are correct, so a pass means the number is the right shape, not that its check digit is mathematically valid. Full check-digit validation, including the two-letter suffix format Revenue introduced later, is a planned upgrade. Either way, a pass never confirms the number is an active Revenue registration — older documents may legitimately show a single trailing letter, so don’t assume that shorter form is a mistake, and use the Revenue lookup or VIES lookup linked below to confirm live status.

Scope: this page and tool cover Irish VAT number format validation only — not VAT registration thresholds, return filing, or reclaiming VAT, none of which a client-side format check can tell you. Use this validator to catch a typo before it reaches Revenue or an invoice; use Revenue or VIES to confirm the number is a live registration.

Content last reviewed 2026-07-07.