What Is a UTR Number? UK Tax Guide for 2026/27

A Unique Taxpayer Reference (UTR) is a 10-digit number HMRC uses to identify a taxpayer or trust within its tax systems. Individuals commonly receive one after registering for Self Assessment. A company has its own Corporation Tax UTR, separate from its Companies House registration number.

What does a UTR look like?

It normally contains 10 digits, sometimes displayed with the letter “K” at the end on a payment slip. Treat the number as confidential personal or business tax information and disclose it only where genuinely needed.

Who receives a UTR?

• individuals registered for Self Assessment;
• sole traders who register to report taxable business income;
• partners and partnerships;
• trusts and estates within the relevant regimes;
• limited companies registered for Corporation Tax.

A sole trader uses the individual Self Assessment UTR; the trade does not receive a separate Companies House identity. A limited company’s UTR belongs to the company, not its director.

UTR versus other identifiers

Where can you find a UTR?

• the Personal Tax Account or HMRC app for an individual;
• previous Self Assessment returns and SA302 calculations;
• HMRC notices to file and payment reminders;
• the company’s Corporation Tax activation or welcome letter;
• Company Tax Returns and HMRC business-tax correspondence;
• an authorised accountant or tax agent’s records.

Do not confuse the UTR with a 13-character Self Assessment payment reference, which normally combines the UTR with a suffix.

How do you get an individual UTR?

1. Check whether Self Assessment is actually required.
2. Register through the relevant GOV.UK service—for example, as self-employed or for another reason.
3. HMRC creates the tax record and issues the UTR.
4. Use the number to enrol for the correct online service where required.

Registration and online-service activation are distinct steps. Allow time before the filing deadline; do not wait until 31 January.

How does a company receive its UTR?

After incorporation, HMRC normally posts the Corporation Tax UTR to the company’s registered office. The company must tell HMRC when it becomes active for Corporation Tax, normally within three months of starting business activity. Keep the registered office monitored so the letter is not missed.

What if the UTR is lost?

First check HMRC online accounts and earlier documents. If it cannot be found, use HMRC’s UTR recovery guidance or contact the appropriate helpline. HMRC will verify identity before disclosing it and may send confirmation by post to the address held.

Accountants cannot invent or look up a UTR from Companies House because it is not public.

Can you have more than one UTR?

Yes, in different legal capacities. An individual can have a personal Self Assessment UTR while a limited company they direct has a separate Corporation Tax UTR. A partnership also has a partnership UTR, and each partner may have an individual UTR.

Does a UTR expire?

The identifier normally remains attached to the taxpayer even if Self Assessment stops. If you later need to file again, HMRC will generally reactivate the existing record rather than issue a new personal UTR. Confirm the correct process before submitting a duplicate registration.

Protecting the number

• do not publish it on invoices or websites unless a specific legal reason applies;
• verify unexpected callers claiming to be HMRC;
• use HMRC’s formal agent-authorisation process;
• store tax documents securely and restrict staff access;
• never send a UTR alongside passwords or authentication codes.

UTR and Construction Industry Scheme

Contractors use a subcontractor’s UTR with other details to complete CIS verification. The subcontractor should still protect the number and provide it through a secure business process. CIS verification does not make the subcontractor genuinely self-employed for all purposes.

Related guide: Self Assessment for self-employed people.

Official guidance

• HMRC: find a lost UTR
• HMRC: register for Self Assessment
• GOV.UK: company tax records

This guide is general information. Use official HMRC channels when obtaining or disclosing a tax reference.