EORI vs UTR vs VAT vs Company Number: UK IDs Explained

UK businesses juggle a confusing pile of reference numbers: an EORI for customs, a UTR for tax, a VAT number for sales, and a company number from Companies House. They look similar, they overlap, and using the wrong one on the wrong form causes real delays. This guide explains what each number is, how to spot them, and which ones you actually need as a trader.

The four UK business numbers at a glance

Each identifier is issued by a different body for a different job. Here is how they compare side by side.

EORI vs UTR: the two most confused numbers

The eori vs utr mix-up is common because both are issued by HMRC and both feel "official". But they do completely different things.

Your EORI number is a customs identifier. Border systems, freight forwarders and couriers use it to link a shipment to your business. Without one, goods can be held at the border. A UK EORI starts with the letters GB followed by 12 digits — see EORI number format & examples for a full breakdown.

Your UTR (Unique Taxpayer Reference) is purely a tax identifier. It's the 10-digit number HMRC uses to track your Self Assessment (for sole traders and partners) or Corporation Tax (for companies). It never appears on customs documents and it is never given to a courier. If a shipping form asks for your EORI, do not enter your UTR.

Quick rule of thumb

• Crossing a border? You need your EORI.
• Filing a tax return? You need your UTR.

UTR number vs VAT number

The utr number vs vat number question trips up newly registered businesses. Both are HMRC numbers, but:

• The UTR is issued automatically when you register for Self Assessment or when you set up a company. Every taxpayer has one, whether or not they trade.
• The VAT number is only issued if you register for VAT — either voluntarily or because you've crossed the registration threshold. Many small businesses never have one.

The VAT number is a public-facing number: it goes on your invoices and can be validated by customers. The UTR is confidential and should be kept private, since it can be used in identity fraud.

How your GB EORI is built from your VAT number

Here's the connection that surprises people: if your business is VAT-registered when you apply for an EORI, HMRC usually builds your GB EORI directly from your VAT number.

The pattern works like this:

In other words, the EORI is GB + your 9-digit VAT number + 000. That's why the two look almost identical — the EORI is a 12-digit version of your VAT registration with three zeros on the end.

If you are not VAT-registered, HMRC issues a standalone GB EORI that isn't derived from a VAT number, but it still follows the GB + 12 digits pattern. You can learn more about the UK-specific rules on our EORI numbers in the UK page, and confirm any GB or XI number is active with the EORI number checker.

Sole trader vs limited company: which numbers apply?

The numbers you hold depend on your business structure.

Sole traders

• UTR — yes, for Self Assessment.
• VAT number — only if VAT-registered.
• Company number — no. Sole traders are not registered at Companies House.
• EORI — yes, if you import or export. It's linked to you as an individual/business, not to a company registration.

Limited companies

• Company number — yes, issued at incorporation.
• UTR — yes, a Corporation Tax UTR (separate from any personal UTR the directors hold).
• VAT number — only if VAT-registered.
• EORI — yes, if trading across borders.

A key point: a limited company has both a company UTR and, if the directors file personal Self Assessment, their own personal UTRs. Keep them separate — using a personal UTR for company tax causes processing errors.

Which numbers appear on customs paperwork vs tax returns

This is where the practical difference really matters.

Notice that the EORI and VAT number live on the trade side, while the UTR and company number live on the tax and legal side. The overlap is that HMRC issues three of the four, which is exactly why they get confused.

Where to find each number

• EORI — on your EORI approval email or letter from HMRC. If you've lost it, follow our guide on how to find your EORI number.
• UTR — on Self Assessment or Corporation Tax correspondence, your HMRC online account, or the "Welcome to Self Assessment" letter.
• VAT number — on your VAT registration certificate and past VAT returns.
• Company number — on your certificate of incorporation and the free Companies House register.

Common mistakes to avoid

1. Entering the VAT number where the EORI is required. They're close but the EORI has the extra 000 — the carrier's system will reject a 9-digit entry.
2. Giving out your UTR. It's confidential; a courier or customer never needs it.
3. Assuming a company number is enough for customs. Companies House numbers mean nothing to border systems — you still need an EORI.
4. Using a personal UTR for company tax. Companies have their own Corporation Tax UTR.

Next step

If you trade across borders, the number that most often causes delays is the EORI. Make sure yours is valid and in the correct GB + 12 digit format before your next shipment. Run it through our EORI number checker to confirm it's active, and if you can't locate it, use our step-by-step guide to find your EORI number. Getting these four IDs straight now saves hours of untangling paperwork later.