UK VAT Number Check: Free VAT Number Validator

Short answer: enter a UK VAT number below. The checker runs HMRC’s check-digit test instantly, so a mistyped or made-up GB number is caught straight away. If it passes, one click takes you to HMRC’s free Check a UK VAT number service to confirm the registration and see the business name and address. XI numbers (Northern Ireland businesses trading goods with the EU) are checked live with the EU’s VIES system.

Use this VAT number check before you reclaim VAT on a supplier’s invoice, before you zero-rate a sale to a business customer, or whenever you need to find out whether a company is VAT registered.

UK VAT number

Check VAT

• GB numbers — check digits verified instantly, then confirm with HMRC
• XI numbers (Northern Ireland) — checked with EU VIES

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Related guides

How to register for VAT →The £90,000 VAT threshold →Check an EU VAT number →

How to check a UK VAT number

1. Find the number. It’s on the business’s VAT invoices and receipts, and often on its website (see how to find a company’s VAT number).
2. Type it in. With or without the GB prefix, and spaces are fine: GB 123 4567 89, GB123456789 and 123456789 all work. Start with XI for a Northern Ireland number used for EU goods trade.
3. Press Check VAT. A GB number is tested against HMRC’s check-digit rule straight away. An XI number is looked up live in VIES.
4. Confirm with HMRC. If a GB number passes, follow the link to HMRC’s checker to confirm it’s currently registered.
5. Compare the name. A registered number only proves the number is live. Make sure the business name and address match the company you’re actually dealing with.

What the results mean

Result	What it means	What to do
Correctly formed (GB)	The number passes HMRC’s check-digit test, so it isn’t mistyped or invented.	Confirm it’s currently registered on HMRC’s checker, and check the name matches your supplier or customer.
Not a valid UK VAT number (GB)	The number fails the check-digit test. No business can be registered under it.	Look for a typo, then ask the business to confirm. Don’t reclaim VAT or zero-rate a sale on this number.
Valid / Invalid (XI)	VIES has, or doesn’t have, a live registration for this XI number.	As above: compare the name, or ask the business to confirm.
Service unavailable (XI)	VIES didn’t answer.	Try again in a few minutes. It says nothing about the number itself.

HMRC’s checker shows the name the business registered with. That can be a limited company’s legal name rather than the shop or trading name you know, so “Hollie Clarke Ltd” for a shop called “Pressed Petals” isn’t a red flag on its own.

What a UK VAT registration number looks like

A UK VAT registration number is 9 digits, written with the country prefix GB. A few have 12.

Format	Example	Who uses it
GB + 9 digits	GB123456789	Almost every VAT-registered business
GB + 12 digits	GB123456789001	Some branches and VAT group members (the last 3 digits identify the branch)
XI + 9 digits	XI123456789	Northern Ireland businesses trading goods with the EU
GBGD / GBHA + 3 digits	GBGD001	Government departments and health authorities (not supported by this checker)

Your VAT number isn’t the same as your company registration number (the 8-character number from Companies House) or your Unique Taxpayer Reference (UTR). If someone gives you an 8-digit number, it’s probably their company number.

GB vs XI VAT numbers

Northern Ireland is part of the UK VAT system, but under the Windsor Framework it follows EU VAT rules for goods. So a Northern Ireland business that sells or moves goods to or from the EU tells HMRC, then uses its usual number with an XI prefix on EU paperwork: XI 123456789 instead of GB 123456789 (gov.uk).

It’s the same registration, just labelled for EU goods trade. That’s why XI numbers are checked in VIES, the EU’s VAT number system, while GB numbers are confirmed with HMRC.

How the check-digit test works

The last two digits of a UK VAT number are check digits, worked out from the first seven. That lets anyone spot a mistyped or invented number without looking it up:

1. Multiply the first seven digits by 8, 7, 6, 5, 4, 3 and 2 in turn, and add the results.
2. Add the last two digits as a two-digit number.
3. The total must divide exactly by 97 (numbers issued before 2010), or do so once you add 55 (numbers issued since).

For a 12-digit branch number, only the first nine digits are tested. Passing the test proves the number is well formed. It doesn’t prove the business is still registered, which is why the checker sends you on to HMRC. Services, and goods sold within the UK or to the rest of the world, still use the GB number.

How to find a company’s VAT registration number

You can’t search HMRC by business name. Its own checking service only works if you already have the number. These are the places to look:

• Invoices and receipts. A full VAT invoice must show the seller’s VAT registration number (HMRC: VAT invoices). This is the most reliable place.
• The business’s website. Usually in the footer, the “About” or “Legal” page, or the terms and conditions.
• Marketplace seller profiles. Amazon and some other marketplaces show a business seller’s details, sometimes including a VAT number, on the seller’s profile page.
• Quotes, order confirmations and email signatures. Larger suppliers often add it everywhere.
• Ask. It’s a normal request. Any VAT-registered business will give you its number.

Companies House doesn’t list VAT numbers, and a company number from Companies House won’t pass a VAT number check.

How to find out if a company is VAT registered

The quickest way to find out if a company is VAT registered is to ask for its VAT number, check it here, then confirm it with HMRC. Three things settle it:

1. HMRC shows a live registration for the number, and
2. the registered name matches the business you’re dealing with, and
3. it’s charging you VAT on a VAT invoice that shows that number.

A business that isn’t registered can’t charge VAT. Plenty of small sellers aren’t registered because their turnover is under the £90,000 VAT threshold, and that’s fine, as long as they don’t add VAT to their prices. If a supplier charges you VAT but can’t give you a number that passes the check, ask for a corrected invoice before you pay.

Why check a VAT number?

Reclaiming VAT on purchases. If you’re VAT registered, you can only reclaim VAT that was properly charged on a valid VAT invoice. If the supplier’s number is fake, HMRC can refuse your claim. A quick check before you pay a big invoice protects the VAT you’re about to reclaim.

Selling to business customers. An overseas seller sending goods worth £135 or less to a UK business doesn’t charge UK VAT if the customer gives a UK VAT number, and the customer accounts for it instead (gov.uk). Checking the number first is how you show you got it right. For EU business customers, use the EU VAT number checker and see selling to EU businesses.

Fraud checks. Invoices with a made-up VAT number are a classic scam. If the name on the register doesn’t match the company that sent the invoice, stop and ask questions.

Keeping proof of the check

Keep a note or screenshot of the result with the date. If you need formal evidence, HMRC’s own service gives VAT-registered businesses proof of when they checked a number, if they also enter their own VAT number (gov.uk).

Worked examples

Priya runs an Etsy shop selling candles from Leeds and is VAT registered. A new wax supplier sends an invoice for £600 plus £120 VAT, total £720, with its VAT number. Priya checks it: it passes the check-digit test, and HMRC’s checker shows it registered to the supplier’s limited company at the same address as the invoice. She pays the £720 and reclaims the £120 on her next VAT return, so the wax costs her business £600.

Tom sells refurbished phones on eBay from Glasgow. A parts dealer he found online quotes £2,400 plus £480 VAT. The VAT number on the quote fails the check-digit test. Tom asks for the correct number. The dealer then says they “aren’t registered yet”. An unregistered business can’t charge VAT, so Tom asks for a revised quote of £2,400 with no VAT. If he’d paid the original, he’d have handed over £480 he couldn’t reclaim from HMRC.

Limitations

• GB numbers: format here, registration at HMRC. For now the checker tests GB numbers against HMRC’s check-digit rule and hands you to HMRC’s own service to confirm the registration. XI numbers are looked up live.
• It confirms registration, not reputation. A registered number tells you the business is VAT registered. It doesn’t tell you it’s trustworthy or that it’s the company on the invoice. Always compare the name.
• New registrations take time to appear. If a business has just registered, its number may not show until HMRC has processed the application.
• No search by name. Like HMRC’s own service, it can only check a number you already have.
• New numbers. HMRC’s check-digit rule covers standard 9 and 12-digit numbers. If a number you’ve been given on an official VAT invoice fails, confirm it on HMRC’s checker before assuming it’s wrong.
• GD and HA numbers aren’t supported. Government department and health authority numbers have a different format.
• The result is a snapshot. A registration can be cancelled later, so check again before large or repeat payments.

Check VAT numbers without checking them by hand

If you’re checking numbers one at a time, your VAT is probably still a manual job. GoodVat handles VAT for online sellers: it works out the right VAT on every sale at checkout, including business sales, sends compliant invoices and files your UK VAT returns through Making Tax Digital. It connects to Shopify, WooCommerce, Amazon, Etsy, Stripe and Xero, among others.

Hand your VAT to someone who does it every day

Tell us where you sell and roughly how much. We'll tell you what you need to be registered for, and can take over the calculations, invoices and returns.

Ask a tax expertor email hello@goodvat.com

A real person replies within one business day

FAQ

How do I check if a UK VAT number is valid?

Enter the number in the checker on this page, with or without the GB prefix. It runs HMRC’s check-digit test instantly, which catches typos and made-up numbers. If the number passes, confirm it’s currently registered on HMRC’s free Check a UK VAT number service, which shows the business name and address.

How do I find a company’s VAT registration number?

Look at a VAT invoice or receipt from them, because a VAT invoice must show the seller’s VAT number. Many businesses also print it in their website footer, terms and conditions or marketplace seller profile. If you can’t find it, ask them. You can’t look up a VAT number by company name with HMRC, and Companies House doesn’t list VAT numbers.

How can I find out if a company is VAT registered?

Ask for their VAT number and check it here, then confirm it with HMRC. If HMRC shows a live registration and the name matches the business you’re dealing with, they’re VAT registered. A business that charges you VAT must be registered and must give you a VAT invoice showing the number. If it can’t, don’t pay the VAT.

What does a UK VAT number look like?

GB followed by 9 digits, for example GB123456789. Some branches and VAT groups have 12 digits. Businesses in Northern Ireland that trade goods with the EU use the same digits with an XI prefix instead of GB.

What is the difference between a GB and an XI VAT number?

They’re the same registration. Northern Ireland businesses that trade goods with the EU under the Windsor Framework put XI in front of their usual number on EU paperwork, for example XI123456789 instead of GB123456789. XI numbers are checked in the EU’s VIES system, GB numbers with HMRC’s check-digit test and its registration service. This checker handles both.

Why does a VAT number show as invalid?

If it fails the check-digit test, it’s mistyped or made up: no business can be registered under it. If it passes here but HMRC doesn’t recognise it, the registration may have been cancelled, the business may never have been registered, or HMRC may still be processing a new registration. Ask the business to confirm the number. Don’t reclaim VAT on an invoice whose number doesn’t check out.

Is the VAT number lookup free?

Yes, with no signup and no limit. HMRC’s Check a UK VAT number service is free too. If you need formal proof of a check for your records, HMRC’s service gives you a reference when you enter your own VAT number as well.

Related guides

• EU VAT number checker: verify EU VAT numbers through VIES.
• How to register for VAT: get your own VAT number, step by step.
• VAT threshold 2026: when a UK business has to register.
• Selling to UK customers: what a UK VAT invoice must show.
• Selling to EU businesses: the reverse charge and why the buyer’s VAT number matters.
• VAT calculator: add or remove VAT at the right rate.