Self Assessment registration and UTR

What's included

• Check that you need to register for Self Assessment
• Choice of the right HMRC registration route
• Preparation of the registration from your details
• Submission to HMRC
• Explanation of what HMRC will send and when to expect it
• Guidance on your first tax return and payment deadlines
• Help if HMRC asks follow-up questions

What Self Assessment registration is

Self Assessment is HMRC's system for collecting Income Tax that is not taken automatically, for example through PAYE on a salary. Before you can file a Self Assessment tax return, you must register. HMRC then gives you a Unique Taxpayer Reference (UTR), a 10-digit number you will use for every return.

A company has its own, separate UTR for Corporation Tax. This page is about your personal UTR.

Who needs to register

You usually need to register if, for example:

• you are self-employed as a sole trader and earned more than £1,000
• you are a partner in a business partnership
• you receive untaxed income such as rent from property or land
• you are a company director with dividends over £10,000 in a tax year
• you have Capital Gains Tax to pay on something you sold
• you have to pay the High Income Child Benefit Charge and do not pay it through PAYE

If your dividends are above the £500 dividend allowance but no more than £10,000, and you do not already file a return, HMRC can collect the tax another way: you tell HMRC after the end of the tax year and before 5 October. Above £10,000, you need a tax return.

Your situation may differ from these examples. If you are unsure, speak to an accountant or check with HMRC before registering.

When to register

You must register by 5 October after the end of the tax year you need to report. The tax year runs from 6 April to 5 April. For example, for the 2025/26 tax year the deadline was 5 October 2026.

The online tax return for 2025/26 and any tax owed are due by 31 January 2027. Registering late can make it hard to file on time, and late filing brings an immediate £100 penalty, with more if the return is very late.

What you receive

After the registration is accepted, HMRC sends your UTR by post to your home address. HMRC's processing time varies and we cannot speed it up, which is why it is best to register early. Once you have your UTR, you can file your first tax return.

How it works

1. Order online and answer a short set of questions about your income.
2. We confirm that you need to register and choose the right route.
3. We prepare and submit the registration to HMRC.
4. HMRC posts your UTR to you.
5. You send it to us if you would like us to prepare your tax return.

What you need to provide

• full name, date of birth and home address
• National Insurance number, if you have one
• phone number and email address
• the type of income you need to report and when it started
• for the self-employed: your business name, address and start date

Your tax return

Registration is the first step. Our Self Assessment tax return service costs £120 and covers preparing and filing the return itself. If you run a company, you may also need annual accounts or help with bookkeeping, VAT and payroll.

Common mistakes

• Waiting until January to register, then not receiving the UTR in time
• Assuming that a company director never needs a personal tax return
• Confusing the company's UTR with your personal UTR
• Registering again when you already have a UTR from earlier years

Frequently asked questions

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