Self Assessment

Get your Unique Taxpayer Reference (UTR)

How to get a UTR number for Self Assessment. Covers registration for sole traders and partnerships, delivery timelines, and what to do if you lose your UTR.

UK-wide
Guide summary

If you need to file a Self Assessment tax return, register with HMRC to get your Unique Taxpayer Reference (UTR). This 10-digit number is sent by post and needed for tax filings. Sole traders must register by 5 October after they start earning over £1,000.

  • Register for Self Assessment to get your UTR
  • UTR is a 10-digit number sent by post
  • Sole traders register by 5 October after starting
  • Self-employed earning over £1,000 must register
  • Partners need separate UTRs for personal and partnership
  • UTR arrives in 10 days (UK) or 21 days (overseas)
  • Keep your UTR safe for tax filings and contracts
  • Lost UTR? Find it on old tax letters or contact HMRC
On this page
UK-wide PartnershipSole Trader

Related guides in Tax & Finance

Before you can file a Self Assessment tax return, you need a Unique Taxpayer Reference (UTR). This 10-digit number identifies you or your business for tax purposes with HMRC.

You cannot apply for a UTR directly. Instead, you register for Self Assessment and HMRC will issue your UTR automatically.

What is a UTR?

Do you need a UTR?

Not everyone needs a UTR. You only need one if you have income that must be reported through Self Assessment.

How to register and get your UTR

The registration process differs depending on your business type.

Sole traders

If you are starting as a self-employed sole trader, register online through HMRC's Self Assessment service. You will need:

  • Your National Insurance number
  • Your name, address, and date of birth
  • The date you started (or will start) self-employment
  • Your business name (if different from your own name)
  • Your business address (if different from home)

Registration takes about 10 minutes online.

Partnerships

Partnerships need two types of registration:

  1. Partnership registration: The nominated partner must register the partnership using form SA400. This creates the partnership UTR.
  2. Individual partner registration: Each partner must also register individually for Self Assessment to get their own personal UTR.

The partnership submits a partnership tax return (SA800) showing total profits. Each partner then reports their share on their personal tax return.

  1. 1

    Check if you need to register

    Use HMRC's online tool to check whether you need to complete Self Assessment. If you are self-employed and expect to earn more than 1,000 pounds gross, you almost certainly need to register.

  2. 2

    Create a Government Gateway account

    If you do not already have one, create a Government Gateway account. You will need this to register and later to file your tax returns.

  3. 3

    Register for Self Assessment online

    Complete the online registration. Sole traders use the standard registration. Partnerships need form SA400 (the nominated partner registers on behalf of the partnership).

  4. 4

    Wait for your UTR to arrive

    HMRC will post your UTR to your registered address. This typically takes 10 working days for UK addresses, or 21 working days if you are abroad.

  5. 5

    Wait for your activation code

    A separate letter will arrive with an activation code. Use this to activate your online Self Assessment account within 28 days.

  6. 6

    Keep your UTR safe

    Store your UTR securely. You will need it for filing tax returns, applying for mortgages, and some business contracts.

When your UTR will arrive

HMRC posts all UTRs for security reasons. They will never email or phone you with your UTR number.

Registration deadlines

Do not leave registration too late. You must register by specific deadlines to avoid problems.

Lost your UTR?

Your UTR is issued for life and cannot be replaced with a new number. If you have lost it, you must recover the original.

Common mistakes to avoid

  • Registering too late: Allow time for your UTR to arrive before you need to file. If you register in January expecting to file before the deadline, you may not receive your UTR in time.
  • Confusing UTR with Government Gateway ID: Your Government Gateway ID (12 digits) is for logging in. Your UTR (10 digits) identifies your tax records. You need both.
  • Not activating your account: The activation code expires after 28 days. If you miss this, you will need to request a new code.
  • Partners forgetting individual registration: Each partner in a partnership needs their own personal UTR as well as the partnership UTR.
SOLE TRADER Requirement

Sole trader UTR registration

As a sole trader, you have one UTR for both yourself and your business. Your business income and personal income are treated as one for tax purposes.

Register online using HMRC's Self Assessment registration. You will receive your UTR within 10 working days (UK) or 21 working days (overseas).

Comparison to other structures:

Sole traders do not have separate business and personal tax identities. Your Self Assessment covers all your income.
Register for Self Assessment if you're self-employed (opens in a new tab)
PARTNERSHIP Requirement

Partnership UTR registration

Partnerships require two levels of registration:

  • Partnership UTR: Registered by the nominated partner using form SA400. The partnership submits a SA800 return showing total profits.
  • Individual partner UTRs: Each partner must register separately for their own UTR. Partners report their profit share on their personal SA100 return.

The partnership does not pay tax directly. Instead, each partner pays tax on their share of the profits through their personal Self Assessment.

Comparison to other structures:

Partnerships are 'tax transparent' - profits flow through to individual partners who pay tax personally.
Register a partnership for Self Assessment (opens in a new tab)
Register for Self Assessment (opens in a new tab)