Check a UK VAT number
Verify any GB VAT number against HMRC in real time — and see exactly what each digit means.
Updated 2026-06-30 · Official source: gov.uk · Live data from HMRC
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A UK VAT number (VAT registration number, or VRN) is the unique reference HMRC issues to a business when it registers for Value Added Tax. Verifying one before you trade matters for a simple reason: you can only reclaim input VAT on a purchase if the supplier is genuinely VAT-registered, and a fake or mistyped number on an invoice can cost you the reclaim and flag your records in an inspection.
This checker validates a number two ways. It runs the official mod-97 checksum instantly in your browser so you can spot a typo before you do anything else, and — when connected to the HMRC Check a UK VAT Number API — it confirms the number is live and returns the registered business name and address, plus a dated consultation number you can keep as proof you checked.
How to check a UK VAT number
- 1
Enter the VAT number
Type the 9- or 12-digit number, with or without the GB prefix and spaces — the checker normalises it for you.
- 2
Read the instant format result
The decoder shows the mod-97 checksum result immediately, so an invalid or mistyped number is caught before you go further.
- 3
Confirm against HMRC
Press check to query HMRC. A valid number returns the registered business name and address as held on the VAT register.
- 4
Keep proof if you need it
When you supply your own VAT number as the requester, HMRC issues a dated consultation number — evidence that you verified the supplier at that moment.
What each digit of a GB VAT number means
A standard UK VAT number is GB followed by nine digits. The first seven are the registration block, and the last two are a checksum derived from them using the mod-97 method. Branch traders add a further three digits, and government departments (GD) and health authorities (HA) use short three-digit numbers instead. Here is a valid number broken down:
- Country prefix:
- United Kingdom
- Base block:
- The 7-digit registration block
- Check digits:
- Mod-97 checksum of the base block
How the mod-97 checksum works
Multiply the first seven digits by the weights 8, 7, 6, 5, 4, 3, 2 and add the results. Add the final two digits (the check number) to that total. If the grand total is exactly divisible by 97 — under either the original rule or the newer "9755" variant — the number is internally consistent. This is why the checker can flag a transposed or mistyped digit the moment you type it, without contacting HMRC. A number can pass the checksum and still not be registered, which is why the live HMRC step matters.
Why verifying a VAT number matters
If you reclaim input VAT on a purchase from a supplier who turns out not to be VAT-registered, HMRC can refuse the reclaim and you carry the cost. Checking the number — and keeping the dated consultation number — is part of reasonable due diligence and protects you against invoice fraud, where a bad actor quotes a real business's VAT number or invents a plausible one. For higher-value or first-time suppliers it is simply good practice.
Reading the result
Valid means HMRC confirms the number is currently registered and returns the business name and address. Not registered means HMRC has no live record of it. Format checked (amber) means we could not reach HMRC at that moment, so only the format and checksum were verified — try again shortly, or treat it as inconclusive for due-diligence purposes.
Finding a VAT number by company name
HMRC's register is searchable by number, not by name, and VAT numbers are not published in Companies House — so there is no official "search by company name" for VAT. The honest route is to find the company on Companies House, get the legal name and number, then ask the supplier for their VRN (it must appear on their VAT invoices) and confirm it here. Our company-name tool does exactly that first step.
How this compares to the GOV.UK checker
The official tool confirms validity and returns a certificate, but stops there. We add the things it leaves out.
| Confirms validity against HMRC | Yes | Yes |
|---|---|---|
| Registered name & address | Yes | Yes |
| Dated proof of check | Consultation number | Certificate |
| Digit-by-digit decode | Yes | No |
| Instant mod-97 checksum (catches typos) | Yes | No |
| Company-name starting point | Yes | No |
| Works offline as a format check when HMRC is down | Yes | No |