UK Tax Identification Number: There Isn't One, and What to Give

Someone has asked you for your UK Tax Identification Number. A foreign bank, a payment platform, a W-8BEN, a CRS self-certification.

The United Kingdom does not issue a TIN. There is no card, no certificate, no number with that name on it.

What exists is a set of numbers that stand in for one, and which one counts depends on who you are and which form is asking. On one point the two official sources actually contradict each other, which is why you can read five articles on this and still not be sure.

Here is what each source says, and a matrix for deciding.

The short answer, by profile

Four of those five are settled. The fifth is not, and it is the one most readers need.

What HMRC actually says a TIN is

HMRC's internal manual defines it plainly:

A unique number (or combination of letters and numbers) in a specified format issued by a jurisdiction for identifying individuals and entities for tax purposes.

Note what is missing from that definition: any requirement that the jurisdiction call it a TIN. A TIN is a function, not a name. The UK fills the function with numbers it calls other things.

The two official positions, and where they diverge

Position one: the OECD country sheet

For the Common Reporting Standard and automatic exchange of information, the OECD publishes a country sheet for each jurisdiction. The United Kingdom sheet names two TINs:

• the Unique Taxpayer Reference (UTR)
• the National Insurance number (NINO)

On this reading, a UK company's TIN is its UTR, the Corporation Tax UTR issued by HMRC.

Position two: HMRC's platform reporting manual

HMRC manual IEIM902330 governs reporting by platform operators. It allocates TINs entity by entity, and for companies it does not say UTR:

For an individual Seller resident in the UK, the TIN will normally be the Seller's NINO.

For a company resident in the UK, the TIN will normally be the Company Registration Number (CRN).

It continues: for a partnership, "the TIN will be the partnership Unique Taxpayer Reference (UTR)"; for a charity, "the TIN will be the CRN"; for a trust, "the TIN will be the trust UTR".

So which is it

Both, in their own contexts.

The practical rule that follows: read the guidance attached to the form in front of you. If it cites the OECD CRS framework, give the UTR. If it is a platform collecting seller data under the platform reporting rules, it will normally want the CRN, and in most cases the platform will tell you which it expects.

If the form gives you no steer and you must choose, the UTR is the number HMRC issued to you specifically for tax, which is what a TIN is defined to be. Where the answer affects a filing, take advice rather than guessing.

The numbers themselves

Two of those are not tax numbers at all, and that is worth being clear about.

The CRN is a company registration number issued by Companies House, a registry identifier, not a tax identifier. It functions as a TIN under one specific regime because HMRC says so, not because it is a tax number.

The VAT number identifies a VAT registration, not the taxpayer. It is never the answer to "what is your TIN", however often forms confuse the two.

Finding your UTR

The UTR is the number most readers end up needing, and HMRC issues it automatically. You do not apply for one directly.

You get one when you register for Self Assessment, or when you incorporate a limited company. The company's Corporation Tax UTR is issued after incorporation, separately from the company registration number.

It arrives in about 15 days, and longer for applicants overseas.

Where to find it:

It may not be labelled "UTR". HMRC's own guidance notes it "might just be called 'tax reference'".

Who does not have a UK TIN

This matters for anyone filling in a form that will not accept a blank.

TINs are not issued to people with no liability to UK tax or National Insurance. That includes:

• those under 16 years of age
• those with no right to work in the UK
• anyone with no UK tax or National Insurance contributions liability

HMRC's manual anticipates the gap:

In the rare circumstance where an Individual or Entity Seller does not have a TIN and is unable to obtain one, the RPO should collect and report all other information as required.

If a form demands a UK TIN and you genuinely do not have one, the correct answer is that none has been issued, not an invented number and not a substitute identifier. Most CRS and FATCA self-certifications have a box for exactly this.

The common mistakes

Giving the VAT number. It identifies a VAT registration, not a taxpayer. Many foreign forms list it as an option because their drafters assumed every country works like theirs.

Giving the company number when the form wants a tax reference. Understandable, and correct under one specific regime, wrong under CRS.

Assuming a certificate exists. There is no UK "TIN certificate". Sites offering to obtain one are selling either a UTR registration you can do yourself, or nothing.

Confusing the UTR with the PAYE reference. Both come from HMRC, both appear on correspondence, and they are different numbers for different purposes.

Using a sole trader's UTR for a limited company. When you incorporate, the company gets its own Corporation Tax UTR. Your personal Self Assessment UTR remains yours and is not the company's.

How the UK compares

The UK is not unusual in lacking a single TIN, but it is unusually confusing because it has so many candidates.

Singapore and Estonia solved this by issuing one number that every government body uses. The UK grew its numbers separately over decades, and the result is the question this article exists to answer.

The summary