Whether you are a small business owner, a VAT-registered sole trader, or a finance professional, knowing how to find and verify a business’s VAT number is an essential compliance skill. Entering into commercial transactions with a supplier that lacks a valid VAT number or worse, one that is fraudulently charging VAT without being registered can leave your business unable to reclaim input VAT and potentially implicated in tax fraud. This comprehensive AccFirm guide explains every method for finding and verifying a UK business VAT number in 2025, from HMRC’s official online checker to reading invoices and using the EU’s VIES system.
What Is a UK VAT Number and Why Does It Matter?
A UK VAT (Value Added Tax) registration number is a unique 9-digit identifier issued by HMRC to businesses that register for VAT. For UK businesses, the number is typically preceded by the prefix “GB” when displayed on official documents for example, GB123456789. For businesses in Northern Ireland trading with EU partners under the Northern Ireland Protocol, the prefix “XI” is used instead.
VAT numbers matter for several critical business reasons:
- Input VAT reclaim: You can only reclaim VAT on purchases if your supplier’s VAT number is valid. HMRC can deny reclaims based on invalid or missing supplier VAT numbers.
- Invoice compliance: VAT-registered businesses are legally required to include their VAT number on every VAT invoice they issue. Issuing or accepting invoices without a VAT number is a compliance breach.
- Fraud prevention: Verifying a supplier’s VAT number protects your business from VAT fraud schemes, particularly missing trader intra-community (MTIC) fraud in supply chains.
- Due diligence: HMRC Notice 726 requires businesses in specified goods sectors (electronics, phones, computers) to conduct “appropriate and proportionate” checks on VAT numbers to avoid liability for supply chain fraud.
- Record keeping: You must retain evidence of VAT number checks including screenshots and timestamps for at least six years under Making Tax Digital record-keeping requirements.
What Does a UK VAT Number Look Like?
A standard UK VAT number is exactly 9 digits long. You may encounter it in several formats:
- Nine digits only: 123456789
- GB prefix followed by nine digits: GB123456789 (standard format on invoices)
- GB prefix with branch suffix (12 digits): GB123456789001 (used by companies with multiple VAT registrations)
- Northern Ireland (post-Brexit EU trade): XI123456789
The VAT number is distinct from a company’s Companies House registration number (CRN), which is an 8-digit or 8-character alphanumeric number. Many businesses display both numbers on their headed paper and invoices, but they serve entirely different purposes.
Method 1: Check Invoices and Business Documents
The fastest starting point for finding a supplier’s VAT number is their documentation. UK law requires VAT-registered businesses to include their VAT number on:
- All VAT invoices issued to other VAT-registered businesses
- Receipts and sales receipts (if the transaction is above £250)
- Credit notes issued against VAT invoices
- Pro forma invoices and quotations (good practice, though not always legally required)
Check the header, footer, or terms section of any invoice or receipt you have received. The VAT number is typically labelled “VAT Reg No”, “VAT Registration Number”, or “VAT No” followed by the digits.
Method 2: Check the Business’s Website
Most VAT-registered UK businesses display their VAT registration number on their website commonly in:
- The footer of every page
- The “About Us” or “Legal” page
- The “Terms and Conditions” page
- The “Contact” or “Privacy Policy” page
- Order confirmation emails or checkout pages (for e-commerce businesses)
If a business claims to be VAT-registered but does not display its number anywhere on its website or documentation, this is a potential red flag worth investigating further.
Method 3: Use HMRC’s Official VAT Number Checker
HMRC provides a free, publicly available VAT number verification service at gov.uk/check-uk-vat-number. This is the most authoritative and reliable method for verifying UK VAT numbers.
How to use the HMRC VAT checker:
- Step 1: Visit gov.uk/check-uk-vat-number
- Step 2: Enter the 9-digit VAT number you want to check (with or without the GB prefix)
- Step 3: The system returns one of three results: Valid (with the registered business name and address), Invalid, or No Match Found
- Step 4: If you are a VAT-registered business yourself, tick the “proof of check” box and enter your own VAT number to generate a dated verification document keep this for your records
The HMRC checker is available 24 hours a day, seven days a week. It is free to use and provides real-time information from HMRC’s VAT database. This is the gold standard for VAT verification in the UK.
Method 4: Contact the HMRC VAT Helpline
If the online service is unavailable or you need urgent assistance, call the HMRC VAT helpline directly:
- Phone: 0300 200 3700
- Opening hours: Monday to Friday, 8am to 6pm
- You will need to provide the company’s full name and postcode to help HMRC locate the correct record
- HMRC can confirm whether a number is valid but may not always disclose the full registered details verbally
Method 5: Use the EU VIES System for European VAT Numbers
The VAT Information Exchange System (VIES), operated by the European Commission, allows you to verify VAT numbers for businesses registered in EU member states. This is essential for UK businesses trading with EU suppliers or customers post-Brexit.
- VIES website: ec.europa.eu/taxation_customs/vies/
- Enter the country code and VAT number to verify
- VIES covers all 27 EU member states but does NOT cover mainland UK (GB numbers) since Brexit only Northern Ireland (XI prefix) is included
- If a result shows “valid” on VIES, the number is currently registered in that EU country
Method 6: Find Your Own VAT Number
If you need to locate your own business’s VAT number (for example, to include it on a new invoice template), check:
- Your VAT Registration Certificate: Issued by HMRC when your business first registered for VAT this is the primary source
- HMRC’s online Business Tax Account: Log in at tax.service.gov.uk/business-account, navigate to VAT or Making Tax Digital for VAT, and your number is displayed prominently
- Previous VAT returns: Your VAT number appears at the top of every VAT return submitted to HMRC
- HMRC correspondence: Any letter about VAT from HMRC will include your number
- Your accounting software: Platforms like Xero, QuickBooks, Sage, and FreeAgent store and display your VAT number in settings
- Your accountant: AccFirm or your appointed agent will have your VAT number on file
What to Do if a VAT Number Is Invalid
If the HMRC checker or VIES returns an “Invalid” result for a supplier’s VAT number:
- Step 1: Contact the supplier directly and ask them to provide their correct, current VAT registration number
- Step 2: Check whether the number has simply been entered incorrectly even one wrong digit will cause a mismatch
- Step 3: Do not pay VAT on the invoice until the number is verified an invalid VAT number means you cannot legally reclaim input VAT
- Step 4: If you suspect deliberate fraud (a business charging VAT without being registered), report it anonymously to HMRC’s Fraud Hotline: 0800 788 887
- Step 5: Seek advice from AccFirm on your liability position in certain circumstances, businesses can be held jointly liable for VAT fraud in their supply chain
VAT Number Fraud: Red Flags to Watch For
VAT fraud costs the UK economy billions of pounds each year. Protect your business by being alert to these warning signs:
- A supplier’s VAT number is listed on the invoice but fails validation on the HMRC checker
- The name and address on the HMRC VAT record does not match the supplier’s details
- A very recently registered VAT number combined with unusually low pricing (common in MTIC fraud)
- The supplier is reluctant to provide their VAT number or provides different numbers at different times
- The invoice structure is inconsistent with HMRC’s VAT invoice requirements
- Unusually large volumes of high-value goods (especially electronics, phones, vehicles) at prices well below market rate
VAT Registration Threshold: When Does a Business Need a VAT Number?
Not all UK businesses have a VAT number. The registration threshold for 2025/26 is £90,000 of taxable turnover in any rolling 12-month period. Businesses below this threshold are not required to register, though they may register voluntarily. If a business’s turnover is below £90,000 and they are not voluntarily registered, they have no VAT number and should not be charging you VAT. Receiving a VAT charge from an unregistered business is a clear indicator of fraud.
Frequently Asked Questions: Finding a Business VAT Number UK
Can anyone look up a VAT number in the UK?
Yes. The HMRC VAT number checker at gov.uk/check-uk-vat-number is publicly available and free to use. Anyone can check whether a UK VAT number is valid and view the registered business name and address.
Is a company number the same as a VAT number?
No. A company registration number (CRN) is issued by Companies House when a limited company is formed. A VAT number is issued by HMRC when a business registers for VAT. The two are separate reference numbers and serve different purposes.
What if a business charges VAT but cannot provide a VAT number?
If a supplier charges VAT but refuses or is unable to provide a valid VAT registration number, do not pay the VAT element of their invoice. You cannot reclaim VAT without a valid supplier VAT number, and the supplier may be committing fraud. Report suspected VAT fraud to HMRC on 0800 788 887.
How often should I re-verify a supplier’s VAT number?
Best practice is to verify a supplier’s VAT number when you first onboard them, then periodically (at least annually) and whenever there is a change in their business details. Businesses can deregister from VAT a previously valid number may become invalid over time.