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.

Start free trialSee how it works

UK VAT numbers. No HMRC connection needed.

accounts-os.com/contacts
Supplier checkLive
Is GB123456789 a real VAT number?
FYes, HMRC has it registered to Northgate Supplies Ltd. That matches the name on the bill you uploaded.
FFinn checked it against HMRC's live VAT register.
Live (UK)

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.

HMRC
Checked at source
Name
Not just a yes or no
No setup
Nothing to connect

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

1

Give Finn the number

Type it in chat, or paste it into the VAT number field on a supplier or customer and press Verify.

2

We ask HMRC

AccountsOS queries HMRC's VAT register for that number. No cached list, no checksum trick.

3

You get the name

HMRC returns the registered business name and address, or tells us it has no record of that number.

4

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

Live register
Straight from HMRC
Not a cached list or a checksum guess
Name + address
What HMRC holds
So you can spot a number that belongs to someone else
In chat
Ask Finn
Or press Verify on the supplier record

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

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HMRC Hub

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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.

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