Free tool · GB + XI
UK VAT checker
Check whether a UK VAT registration number is valid and currently registered. GB numbers are checked live through a commercial VAT data service for Great Britain and come back with the registered business name and address. Northern Ireland numbers with the XI prefix are checked in the EU's VIES.
Include the country prefix. EU numbers are checked against VIES in real time, UK numbers with a separate live check.
What the UK VAT checker checks
- Prefix: GB for a UK VAT number, XI for a Northern Ireland number used for trade in goods with the EU.
- Format: 9 digits, 12 digits for a branch, or GD/HA plus 3 digits for government and health bodies. The tool checks the format before it asks the register.
- Registration: a live check through a commercial VAT data service for GB numbers, in VIES for XI numbers. A registered number comes back with the business name and address on record.
The tool checks the format of GB numbers, not their check digits; the register is the final word on whether a number exists.
When to check a UK VAT number
- Before you invoice without UK VAT: when you treat a UK customer as a business, for example for services outside the scope of your VAT, confirm the number first and keep the result with its date and time.
- Supplier onboarding: compare the registered name and address with the invoice before you pay, a common check against invoice fraud.
- Stored numbers: registrations are cancelled when businesses close or deregister. Check stored numbers again before large orders.
EU VAT numbers? Use the VAT number checker, which takes all EU, XI and GB numbers, or the bulk VAT validator for up to 50 at once. The UK VAT number format page has the regex.
Check UK VAT numbers by API
curl -G https://api.vatcheckapi.com/v2/check \
-d vat_number=GB980780684 \
-H "apikey: YOUR-API-KEY"
The response has format_valid, checksum_valid and registration_info with is_registered, name, address and checked_at. consultation_number is always null for GB numbers. See the documentation for errors and costs.
Frequently asked questions
How do I check a UK VAT number?
What does a UK VAT number look like?
Why is a UK VAT number not found in VIES?
What is the difference between GB and XI?
Do I get a consultation number for a UK VAT number?
The check did not go through. What now?
Can I check UK VAT numbers automatically?
VAT validation API
Validate VAT numbers in your app
vatcheckapi checks the format and checksum of EU and UK VAT numbers and confirms the registration live (VIES for EU numbers), with company name and address where the country provides them.
/v2/check documentation VAT number API All documentation
150 free validations every month. No credit card required.
GET https://api.vatcheckapi.com/v2/check?vat_number=LU26375245
{
"country_code": "LU",
"vat_number": "26375245",
"format_valid": true,
"checksum_valid": true,
"registration_info": {
"is_registered": true,
"name": "AMAZON EUROPE CORE S.A R.L.",
"address": "38, AVENUE JOHN F. KENNEDY\nL-1855 LUXEMBOURG",
"address_parts": null,
"checked_at": "2026-10-16T09:12:44.000000Z"
},
"registration_info_history": []
}