Tax and filings
Is that VAT number actually real?
Ask Finn, or press Verify on a supplier. AccountsOS checks the number against HMRC's VAT register and hands back the business name and address HMRC holds for it.
UK VAT numbers. No HMRC connection needed.
In short
AccountsOS checks UK VAT registration numbers against HMRC's VAT register and returns the registered business name and address. You can ask Finn in chat, press Verify next to the VAT number field when adding or editing a contact, or use the Check VAT number card on the HMRC page. A not-registered answer is a real answer from HMRC rather than an error. It covers UK (GB) VAT numbers, and you do not need to connect HMRC MTD to use it, because AccountsOS checks using its own HMRC application credentials.
Everything it does
Checked against HMRC, not a formula
- Queries HMRC's VAT register directly, so the answer is HMRC's answer
- Returns the registered business name and address, not just valid or invalid
- A not-registered result is a genuine answer from HMRC, and we say so plainly
- UK (GB) VAT numbers, with or without the GB prefix
Where you actually need it
- Ask Finn in chat: "is GB123456789 a real VAT number?"
- Press Verify beside the VAT number when adding or editing a contact
- Use the Check VAT number card on your HMRC page
- Finn flags it when the registered name does not match the contact you are saving
Nothing to set up
- No HMRC connection required: AccountsOS checks with its own credentials
- Works from day one of your trial
- No separate subscription and no per-check charge
- Nothing is written to your books by a check, it is read-only
Capabilities at a glance
Check a UK VAT number against HMRC's VAT register
See the registered business name and address HMRC holds
Ask Finn to check a number in plain English
Verify button beside the VAT field on contacts
Name-mismatch warning against the contact you are saving
Accepts numbers with or without the GB prefix
Works without connecting HMRC MTD
Read-only: a check never changes your books
How It Works
Give Finn the number
Type it in chat, or paste it into the VAT number field on a supplier or customer and press Verify.
We ask HMRC
AccountsOS queries HMRC's VAT register for that number. No cached list, no checksum trick.
You get the name
HMRC returns the registered business name and address, or tells us it has no record of that number.
Act on a mismatch
If the registered name is not the business on your bill, that is the moment to query it, before the VAT reaches your return.
By the numbers
Real-world Use Cases
Onboarding a new supplier
They send an invoice with a VAT number on it. Check it before you set them up, and you find out immediately whether HMRC has that number registered to them or to somebody else.
Before you reclaim input VAT
Reclaiming VAT against a number that is not registered is the kind of thing that surfaces at exactly the wrong moment. Check it while the bill is in front of you.
An invoice that feels off
Invoice redirection fraud usually gets the details nearly right. A VAT number registered to a different company is a cheap, fast tell.
Tidying an inherited ledger
Migrated a book full of suppliers with VAT numbers nobody ever checked? Ask Finn about the ones you are unsure of.
Why founders pick this over the spreadsheet
Catch a wrong VAT number before it reaches your VAT return
See who HMRC actually has registered, not just a valid or invalid flag
Check without leaving the conversation or the contact record
No HMRC connection, no setup, no extra charge
A clear no when HMRC has no record, instead of a vague error
Frequently Asked Questions
Where does the answer come from?
HMRC. AccountsOS queries HMRC's VAT register for the number you give it and reports back what HMRC returns. It is not a checksum calculation or a cached copy of a list, which is why it can tell you the registered business name and not just whether the format looks plausible.
What do I get back?
For a registered number: the business name and address HMRC holds against it. For a number HMRC has no record of: a plain no. That no is a real answer from HMRC, not a failure, and we show it as such.
Do I need to connect HMRC to use it?
No. This check uses the AccountsOS application's own HMRC credentials, so it works whether or not you have connected HMRC MTD for filing. Connecting HMRC MTD is only needed to file VAT returns.
Does it work for non-UK VAT numbers?
Not yet. This checks UK (GB) VAT registration numbers, because it uses HMRC's register. EU VAT numbers are validated through a different service (VIES) which is not wired in today.
Can Finn check a number for me?
Yes. Ask in plain English, for example "is GB123456789 a real VAT number?", or ask Finn to check a supplier you are about to add. If the registered name does not match the contact, Finn tells you, because the mismatch is usually the thing worth knowing.
Does checking a number change anything in my books?
No. A check is read-only. It does not create a contact, edit a VAT number, or touch a return. You decide what to do with the answer.
Explore more of AccountsOS
VAT & Making Tax Digital
Your VAT return builds itself with every transaction. File when you're ready.
HMRC Hub
One place for every HMRC interaction.
Contacts (Lightweight CRM)
Every supplier, customer, contractor, in one searchable list, linked to every transaction.
Ask Finn (AI Chat)
Talk to your books. Ask anything. Finn does the work.
Ready to try Check a VAT Number?
Set up in minutes. Finn works in the background on your books, wherever you're based.
Included in your subscription. No per-check charge.
Free for 14 days, no credit card, cancel anytime