What is a VAT Number? UK Format and Examples

A VAT number is the nine-digit reference HMRC issues to a business when it registers for VAT, and it is also known as a VAT registration number or VRN. The number is sometimes written with GB in front, as in GB123456789, and a VAT-registered business must include it on every invoice it raises.

If your VAT-registered business ever needs an EORI number for moving goods, HMRC builds it from your VAT number by adding GB at the start and 000 on the end, so 123456789 becomes GB123456789000.

The two look alike for exactly that reason, yet one’s for VAT and the other’s for customs paperwork when goods move, and the list further down lines them up against your company number and UTR.

What is a VAT number going to mean for you in practice? That depends on whether your turnover is near the £90,000 registration threshold, whether you trade goods between Northern Ireland and the EU, and whether you’ve applied and you’re still waiting for your number to arrive.

What is a VAT number? A nine-digit HMRC reference

HMRC hands out a VAT number once your registration goes through, and the number is registered to your business name and address. On HMRC’s own pages it’s your VAT registration number or VRN, and some guides use VAT identification number for the same thing.

HMRC sends four things by post once you’re registered:

• You get the nine-digit number itself.
• You get instructions for setting up a business tax account, which is how you reach HMRC’s online VAT service.
• You’re told when your first VAT return and payment are due.
• You get confirmation of your effective date of registration.

Hang on to that paperwork. Your VAT registration certificate shows the number and the effective date, and you’ll need both if you later apply for an EORI number.

From the effective date you can charge VAT on your sales and reclaim VAT on your purchases. Making Tax Digital for VAT is handled as well, because HMRC enrols the business itself unless it’s exempt or you’ve asked for an exemption.

UK VAT number format: GB plus nine digits

A UK VAT number is nine digits long. The letters GB sometimes sit in front, and HMRC’s own checker accepts a number typed either way, so 123456789 and GB123456789 both work.

Here’s a VAT number example with made-up digits: a business issued 123456789 might print GB123456789 on its invoices. With the prefix, that’s 11 characters in total, two letters followed by the nine digits.

Ask how many digits a UK VAT number has and HMRC’s checker answers nine. Your own GB VAT number is printed on your VAT registration certificate, which is where the checker points you to find it.

The prefix changes for Northern Ireland businesses that trade goods with the EU.

An XI VAT number keeps the same digits

If you trade goods under the Northern Ireland Protocol, you need an XI VAT number to do it. You’re eligible to trade under the Protocol if any one of these applies:

• You make the sale while the goods are physically in Northern Ireland.
• Business goods reach you in Northern Ireland from an EU supplier that’s VAT-registered.
• Goods leave Northern Ireland for an EU country, whether you’ve sold them or you’re just moving them.

The digits stay the same. You tell HMRC you’re eligible through its online service, HMRC confirms by email, and from then on you put XI in front of your usual number, so GB123456789 becomes XI123456789.

Use the XI version on every document when you’re dealing with EU customers or suppliers, invoices included. HMRC warns that skipping the notification or the prefix could leave you paying or charging the wrong VAT on goods.

The eligibility test and the notification service sit on GOV.UK’s page about selling or moving goods between Northern Ireland and the EU.

Not every business has a VAT number

HMRC issues a VAT number as part of registration, so the question that decides whether you’ll have one is whether you need to register.

For a UK-based business, the turnover test has two parts. Registration becomes compulsory once your total taxable turnover over the previous 12 months passes £90,000, or as soon as you expect to pass £90,000 within the coming 30 days.

The test is about going over, so turnover of exactly £90,000 doesn’t trigger it. Taxable turnover means everything you sell that isn’t exempt from VAT or outside its scope, and zero-rated sales still count.

The threshold rose from £85,000 to £90,000 on 1 April 2024. For how the tax itself works, see the What is VAT? guide.

Other rules can apply too. If you only sell exempt or out-of-scope goods and services, you don’t have to register, unless you’re in Northern Ireland and buy more than £90,000 of goods in any 12 months from VAT-registered EU suppliers for the business. Businesses based outside the UK that supply goods or services here must register whatever their turnover. Below the threshold, you can choose to register voluntarily.

The usual route is an online application, and GOV.UK’s register for VAT online page lists what you’ll need for it.

HMRC publishes its expected reply times for VAT in its ‘check when you can expect a reply’ tool, which it updates weekly. That’s the place to look once you’ve applied.

If you’re a sole trader, the sole trader VAT registration guide walks through the process for your set-up.

Your VAT registration number goes on every invoice

Once you’re registered, your VAT number has to appear on every invoice you raise. Sales at the standard or reduced rate to another VAT-registered business need a VAT invoice, with a few exceptions (self-billing arrangements are one).

Smaller sales get a lighter format. HMRC allows a simplified invoice where the supply is £250 or less including VAT, and even that version carries your name, address and VAT number.

The awkward stretch is between applying and receiving your number. You can’t show VAT on an invoice until the number arrives, but HMRC lets you raise your prices to cover the VAT you’ll owe.

Say you finish a £2,000 standard-rated job while you’re waiting. Adding VAT at the 20% standard rate, you’d invoice £2,400 without showing VAT as a separate line. When your number comes through, you reissue that invoice showing £2,000 plus £400 VAT.

The total stays the same, and a VAT-registered customer can then reclaim the £400 on their VAT return. The input and output VAT guide explains how the VAT you charge and the VAT you pay net off.

Checking works in the other direction too. HMRC’s Check a UK VAT number service confirms whether a number is valid and shows the business name and address it’s registered to.

You can’t search it by business name. A VAT-registered business that enters its own number alongside the one it’s checking gets a reference number proving when the check was done.

The step-by-step version is in the guide on how to find and verify a VAT number.

VAT number vs company number: telling four numbers apart

Four reference numbers turn up in the same paperwork, and three of them come from HMRC. Their shapes give them away:

• A VAT number comes from HMRC when you register for VAT, and it’s 9 digits, sometimes with GB in front, as in GB123456789.
• A company registration number comes from Companies House when a company is registered, and it’s 8 characters: 8 digits, or 2 letters then 6 digits.
• A UTR comes from HMRC when you register for Self Assessment or set up a limited company, and it’s 10 digits.
• A GB EORI for a VAT-registered business comes from HMRC when you apply for one to move goods, and it’s GB, your 9 VAT digits, then 000, as in GB123456789000.

The VAT number vs company number difference comes down to who issues them: HMRC for one, Companies House for the other.

VAT number vs UTR is closer, since both come from HMRC, and the digit count, nine against ten, tells them apart.

The VAT number vs EORI number pairing is where the shapes overlap, and it’s the EORI you may need when moving goods between Great Britain and other countries.

Before you quote your VAT number

That’s the answer to what is a VAT number in practice: a nine-digit HMRC reference that arrives with your VAT registration and then goes on every invoice you raise. The GB in front is optional when you check a number, and XI goes in front of the same digits for Northern Ireland goods trade with the EU once HMRC has confirmed you.

Anyone whose turnover hasn’t gone over the £90,000 threshold, or who only sells exempt goods and services, may not have one at all.

Before quoting a number anywhere, check you’ve got the right one of the four. The company number and UTR look different, and the EORI simply extends the VAT number with 000.

If you’re checking someone else’s number, the guide to finding and checking a VAT number covers the HMRC service.

Key Takeaways

• A VAT number is the nine-digit reference HMRC issues when a business registers for VAT, also called a VAT registration number or VRN.
• GB in front of the digits is optional when you check a number, and Northern Ireland businesses trading goods with the EU under the Protocol add XI once HMRC confirms them.
• Registration becomes compulsory in several situations, including when taxable turnover over the previous 12 months passes £90,000.
• Once registered, your VAT number goes on every invoice you raise, and you can’t show VAT on an invoice before the number arrives.
• A VAT number isn’t a company number or a UTR, but a VAT-registered business’s GB EORI is built from it.