UK VAT Number Checker: Verify a VAT Registration Number
A UK VAT registration number has a built in structure, so a quick check can tell you at once whether a number is even possible before you rely on it. The tool below cleans a number, works out whether it is the right shape, and tests the check digit that guards against typos. The guide then explains how to confirm a number is actually registered, and why that matters when you reclaim VAT.
Check a UK VAT number
Enter a VAT number with or without the GB prefix, and with or without spaces. The checker strips out anything that is not a letter or a digit, decides what kind of number it is, and tests the check digit. It updates as you type.
Type or paste a VAT number to check it.
This confirms a number is correctly formed. It does not tell you whether the number is currently registered or who holds it. For that, use the free HMRC service explained lower down.
What a UK VAT number looks like
A standard UK VAT registration number is nine digits. It is often written with a GB prefix, so you see eleven characters in all, and it is usually grouped for readability, for example GB 123 4567 89. The spaces carry no meaning, so a number is just as valid written as one block of nine digits.
A few variations exist. Some businesses that register separate branches under one registration use a longer number with a three digit branch suffix on the end. Government departments use a different series that begins with the letters GD followed by three digits. A small number of public bodies sit in their own number ranges. For everyday checking of a supplier or customer, the nine digit number is what you will nearly always meet.
| What you see | What it is |
|---|---|
| GB and nine digits | A standard Great Britain VAT registration number |
| Nine digits and a three digit suffix | A registration that covers separate branches, with the suffix identifying the branch |
| GD and three digits | A UK government department |
| XI and nine digits | A Northern Ireland number used for goods traded with the EU |
The check digit, and how this tool uses it
A UK VAT number is not a random string. The last two digits are a check digit worked out from the first seven using a modulus 97 calculation. Because the digits are tied together by that sum, a single mistyped digit almost always breaks the maths and produces a number that fails the check. That is what lets this tool flag a number as wrongly formed the moment you finish typing.
Passing the check digit is a strong sign that a number was copied correctly. It is not proof that the number was ever issued or is still live. Think of it as spelling the number correctly rather than confirming the business behind it, which is the next step below.
What this checker can and cannot tell you
The tool on this page runs entirely in your browser and looks only at the number itself. It is quick, private, and good at one job, catching numbers that cannot be right.
- It can tell you that a number is the wrong length, contains letters where it should not, or fails the check digit.
- It can tell you that a number is correctly formed and therefore worth trusting enough to check against HMRC.
- It cannot tell you whether the number is currently registered, whether it has been cancelled, or which business it belongs to.
How to confirm a VAT number is actually registered
HMRC runs a free online service called Check a UK VAT number. You enter the number and it tells you whether it is valid and shows the name and address of the business it is registered to, so you can match it against the supplier in front of you.
There is one more feature worth knowing. If your own business is VAT registered, you can enter your own VAT number and ask the service to record the check. It gives you a dated reference number that proves you looked the number up, which is useful evidence if HMRC ever questions a claim. HMRC also publishes an API, so software can check numbers automatically.
- Copy the supplier VAT number from their invoice or quote, and run it through the format checker above to rule out a typo.
- Open the HMRC Check a UK VAT number service and enter the number.
- Confirm the name and address it returns match the business you are dealing with.
- If you are VAT registered, enter your own VAT number and save the dated reference number with your records.
Checking EU and Northern Ireland numbers
Since the United Kingdom left the EU VAT area, GB numbers are no longer held on the EU system. To check a VAT number from an EU member state you use the EU service called VIES, the VAT Information Exchange System. HMRC has its own service for GB numbers instead, which is the one described above.
Northern Ireland is a special case. Under the Windsor Framework, a Northern Ireland business that trades goods with the EU uses a number that begins with XI in place of GB, for example XI 123 4567 89. XI numbers can be checked on VIES alongside EU numbers, while the rest of a Northern Ireland business still uses its GB number for other purposes.
Why checking a supplier VAT number matters
This is not box ticking. To reclaim the VAT a supplier charges you, HMRC expects you to hold a valid VAT invoice, and one of the details a full VAT invoice must show is the supplier VAT registration number. If that number is wrong or the invoice is not valid, HMRC can refuse the claim, so a bad number can cost you real money.
There is a fraud angle too. VAT is a target for missing trader fraud, where a supplier charges VAT and disappears without paying it over. HMRC expects businesses to carry out reasonable checks on who they trade with, and can deny a claim where a business knew or should have known it was connected to fraud. Verifying a VAT number is one of the simplest checks in that due diligence, and keeping the HMRC reference number shows you did it.
Where to find a VAT number
A supplier VAT number appears on their invoices, on quotes and order confirmations, and often in the footer of their website or their terms. Your own number sits on your VAT registration certificate, which you can view in your HMRC business tax account, and on every VAT invoice you issue. If a supplier charges VAT but will not show a number, treat that as a warning rather than a detail.
Common results and what they mean
| Result | What to do |
|---|---|
| Valid format | The number is well formed. Confirm it is live and matches the business on the HMRC service. |
| Check digit does not match | Almost always a typo. Recheck the exact number against the invoice and try again. |
| Wrong length | You may have included a country code, a branch suffix, or an extra digit. Enter the nine digit number on its own. |
| Valid format but HMRC finds nothing | The number may be cancelled or never issued. Do not reclaim VAT against it, and query the invoice with the supplier. |
Need to work out the VAT on a figure while you are here? Our free calculator adds or removes VAT at any rate in a couple of clicks.
Open the VAT calculatorFrequently asked questions
Start with the format checker above, which tests the length and the check digit and catches typos at once. Then confirm the number is live, and belongs to the right business, on the free HMRC Check a UK VAT number service, which shows the registered name and address.
A standard UK VAT number is nine digits, often shown with a GB prefix and grouped for readability, for example GB 123 4567 89. Some branch registrations carry a three digit suffix, government departments use a GD prefix, and Northern Ireland goods trade uses an XI prefix.
Yes. The last two digits of a UK VAT number are a check digit calculated from the earlier digits using a modulus 97 method. It means a mistyped number nearly always fails, which is how the checker on this page spots an error before you rely on the number.
The HMRC Check a UK VAT number service shows the name and address registered to a valid number, so you can match it against the business you are dealing with. The format checker on this page cannot do that, as it only looks at the number itself.
This tool is built for the UK format. EU numbers are checked on the EU VIES service, and Northern Ireland numbers that begin with XI can also be checked on VIES. GB numbers left the EU system after Brexit, which is why HMRC runs its own service for them.
To reclaim the VAT a supplier charges, you need a valid VAT invoice showing their VAT number. If the number is wrong, HMRC can refuse the claim. Checking also forms part of the due diligence HMRC expects, since VAT is a target for missing trader fraud.
A well formed number can still be cancelled, or never have been issued. If the HMRC service does not return a match, do not reclaim VAT against that number. Go back to the supplier, query the invoice, and ask them to confirm their current registration.
Your VAT registration number is on your VAT registration certificate, which you can view in your HMRC business tax account, and it appears on every VAT invoice you issue. You must show it on your invoices so your customers can reclaim the VAT you charge.
Sources: HMRC, Check a UK VAT number and its supporting service pages; HMRC VAT Notice 700, the VAT guide, on valid invoices and evidence for input tax; HMRC VAT Notice 726 on joint and several liability for unpaid VAT, and HMRC guidance on the due diligence expected to avoid involvement in VAT fraud; gov.uk guidance on trading goods between Northern Ireland and the EU; EU VIES service. Figures and rules are current for 2026 and are general guidance, not advice on your own circumstances.