A company VAT number is the 9-digit registration number HMRC issues when a business registers for VAT, usually written with a GB prefix, for example GB 123 4567 89. You can find your own in the VAT registration letter HMRC sends by post, in your VAT online account, and on your VAT returns and invoices. A company only has one if it is VAT registered, which is compulsory once taxable turnover passes £90,000 in any rolling 12 months.
What a VAT number is
When HMRC registers a business for VAT, it allocates a registration number that identifies that business for VAT purposes. HMRC says that after you register you will get "a 9-digit VAT registration number which you must include on all invoices you raise", together with confirmation of your "effective date of registration", the date from which you charge VAT and can reclaim it.
The number belongs to the VAT registration, not to the company as a legal entity. Companies House does not issue VAT numbers, and a company that is not VAT registered has no VAT number at all, however long it has existed. A company that joins a VAT group loses its own number: HMRC cancels the members' previous numbers and issues a new one to the group, which "must then be used by all the group members".
What a UK VAT number looks like
| Format | Example | Used by |
|---|---|---|
| 9 digits | 123 4567 89 | Most VAT-registered businesses in Great Britain |
| GB + 9 digits | GB 123 4567 89 | The same number with the UK country prefix, required on invoices for cross-border supplies |
| XI + 9 digits | XI 987 6543 21 | Businesses trading in goods under the Windsor Framework in Northern Ireland |
| 654 + 6 digits | 654 xxx xxx | Health authorities |
| GD + 3 digits, or 9 digits starting 888 8 | GD123 | Government departments |
The XI prefix does not create a separate registration. HMRC's guidance says that businesses trading under the Windsor Framework "should use the prefix XI to your UK VAT registration number", so the nine digits stay the same.
Do not confuse the VAT number with the other numbers a company holds. The company registration number from Companies House is up to eight characters and can start with letters such as SC or NI. The Unique Taxpayer Reference is a 10-digit number for Corporation Tax. An EORI number, used for customs, also starts with GB but is a separate registration.
How do I know my VAT number?
- Your registration letter. HMRC sends the VAT number, your first return and payment dates and your effective date of registration by post after it approves the application;
- Your VAT online account. HMRC says you "must sign up for a VAT online account as soon as you receive your VAT registration number". HMRC's manual says the registration certificate "can be found in the VAT online account", so it is the quickest place to look once you are signed up (see our guide to the VAT certificate);
- Your invoices. A full VAT invoice must show "the name, address and VAT registration number of the supplier", so any VAT invoice you have issued since registering will show it;
- Your accountant. If an agent registered you or files your returns, it will have the number on file.
HMRC's Check a UK VAT number service cannot help you find a lost number: HMRC says "you cannot use this service to check if a business or organisation is registered for VAT by searching its name". It also cannot be used while you are still waiting to hear back on an application.
Where your VAT number must appear
Once registered, the number goes on every VAT invoice. For supplies of £250 or less, including VAT, a simplified invoice is allowed, but it must still show "your name, address and VAT registration number". For cross-border supplies, HMRC's guidance requires "the letters 'GB' in front of your registration number". Businesses also show the number in their email footers, on their websites and in supplier onboarding forms, because customers will ask for it before they pay.
Worked example: the first invoice after applying
On 1 May a consultancy signs a £100,000 contract to be paid at the end of May, so it knows its taxable turnover in the next 30 days alone will go over £90,000. It applies straight away, and its effective date of registration is 1 May. Until the number arrives, HMRC says you "cannot include VAT on your invoices", but you can raise prices to cover the VAT. The consultancy invoices £120,000, and once the number arrives it reissues the invoice showing £100,000 plus £20,000 VAT and its new VAT number. The customer pays nothing extra but can now reclaim the £20,000 on its next return.
Checking someone else's VAT number
To check a supplier's or customer's number, HMRC's free service confirms "if a UK VAT registration number is valid" and "the name and address of the business the number is registered to". If you enter your own VAT number as well, you get dated proof of the check. Our UK VAT checker guide covers how to use that evidence to protect your input VAT claims. EU numbers are checked on the EU's VIES system instead.
When the number changes
A VAT number normally stays the same for the life of the registration, and changes of name or address are updated against the same number. When a business changes owner or legal status, for example a sole trader incorporating, HMRC says "you may be able to transfer a VAT registration number" to the new entity; otherwise the new entity registers and gets its own number. When a VAT group is disbanded, its number is cancelled and members that still need to be registered must "register for VAT again to get a new registration number". The rules on when you must register are in our guide to the VAT threshold.
Primary sources: HMRC's guidance on registering for VAT, VAT Notice 700/21, Check a UK VAT number, VAT Notice 725 and manual VATGPB9400.
If you are approaching the threshold, our VAT registration team can handle the application and your first return, and our VAT compliance service keeps invoices, returns and registration details in order after that.