VAT number

A VAT number is the unique identifier a national tax authority issues to a business once it registers for value-added tax, used on every VAT invoice and to validate the business in cross-border EU transactions through the VIES system.

Applies in: United Kingdom European Union

Every VAT-registered business has a VAT number. It is what the tax authority uses to match your VAT returns to your invoices, what your buyer's accounting team needs to claim input tax on what you sold them, and what cross-border counterparts use to validate that you are who you say you are.

The format is country-specific. UK numbers are GB followed by 9 digits (e.g. GB123456789). Ireland is IE followed by 7-8 digits plus a check letter. Germany is DE followed by 9 digits. France is FR with 11 characters. Italy uses IT followed by 11 digits. The EU's VIES (VAT Information Exchange System) is a free online tool that validates any EU VAT number in real time. UK numbers post-Brexit are validated against HMRC's own service.

On the invoice, the supplier's VAT number is mandatory for any VAT-registered supplier. For reverse-charge cross-border B2B services within the EU, the buyer's VAT number must also appear (this is what qualifies the transaction for reverse charge in the first place). Missing or invalid VAT numbers on these invoices can cause the buyer's tax authority to disallow the reverse-charge treatment, which gets messy.

Common questions about VAT number

How do I get a VAT number?

Register for VAT with your national tax authority once you cross the registration threshold (or voluntarily, if below). In the UK, that is GBP 90,000 of taxable turnover over a rolling 12 months, registered via HMRC online. Each EU member state has its own threshold and registration portal. The number is usually issued within a few weeks of application.

How do I validate a customer's VAT number?

For EU VAT numbers, use the EU's VIES portal (ec.europa.eu/taxation_customs/vies). For UK numbers post-Brexit, use HMRC's own checker (gov.uk/check-uk-vat-number). Both are free and return the registered business name. Validating the buyer's number is essential before applying reverse charge, because an invalid number invalidates the reverse-charge treatment.

What format is a UK VAT number?

Standard UK VAT numbers are GB followed by 9 digits, sometimes followed by a 3-digit branch identifier (e.g. GB123456789001). Government departments use GBGD followed by 3 digits. Health authorities use GBHA followed by 3 digits. Cross-border, only the GB-plus-9-digits form is recognised by VIES.

Use JupiterInvoice for VAT number

VAT number on a JupiterInvoice invoice is a field, a label, and an audit trail your buyer can act on without an email back-and-forth.

Invoicing in the United Kingdom

How to send an invoice in the UK: GBP, VAT, sort code and account number, IBAN for international, BACS and Faster Payments. Plain-English gu...

Invoicing in Ireland

How to send an invoice in Ireland: VAT number, EUR, IBAN, BIC, SEPA. With cross-border EU billing notes and reverse-charge basics.

Related terms

VAT Reverse-charge VAT TIN EIN ABN

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