UK VAT number checker
Paste a VAT number any way you have it. You see whether the format and check digits are valid, and you can copy it in the three forms people ask for: with spaces, without, and digits only.
How the check works
A standard UK VAT number is 9 digits. Multiply the first seven by 8, 7, 6, 5, 4, 3 and 2 and add them up. Add the last two digits read as a number. If the total divides exactly by 97, the number passes the original rule. Newer numbers, those starting 100 or above, are also accepted under a second pattern (the “9755” rule: add 55 to the total first, then it must divide by 97). The rule is the one the open-source python-stdnum library uses; HMRC publishes the lookup service, not the formula.
Passing means the number is well formed. It does not mean it is registered, active, or belongs to the business you think it does. For that, use HMRC’s own check a UK VAT number service.
Questions people ask
What does a UK VAT number look like?
GB followed by 9 digits, usually written GB 123 4567 89. A branch of a business adds 3 more digits (12 in all). Government departments use GD and 3 digits, and health authorities use HA and 3 digits.
What does this checker actually check?
That the format is one the UK uses, and that the last two digits agree with the first seven under the check-digit rule (a weighted sum that must divide by 97, with a second accepted pattern for newer numbers). It cannot tell you whether HMRC has the number on its register.
How do I check a VAT number is registered?
Use the gov.uk service "Check a UK VAT number". It shows the registered name and address if HMRC holds the number. This checker only checks the format and the check digits, so use that service to confirm the number is registered.
Should I write the VAT number with spaces and the GB prefix?
A VAT invoice must show your VAT number; gov.uk does not set a spacing. The usual habit is GB then the digits, with or without spaces, and the digits alone where a form asks only for the number. Copy whichever form the place you are pasting into expects.
Is a VAT number the same as a company number?
No. A company number is the 8-character number Companies House gives a company when it is set up. A VAT number is issued by HMRC when a business registers for VAT. They are unrelated.
Sources
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