How to Register as Self-Employed with HMRC: Step-by-Step

The Accounted Business Team·11 February 2026·7 min read

Why You Need to Register

If you have started working for yourself — whether freelancing, running a small business, or doing regular paid work outside of employment — you need to tell HMRC. Registration is a legal requirement and is the first step to paying the right amount of income tax and National Insurance on your self-employed earnings.

You must register if your self-employed income exceeds £1,000 in a tax year (the trading allowance threshold). Even if your income is below this, you might choose to register voluntarily to build National Insurance credits or to claim losses against other income.

The Deadline: 5 October

You must register with HMRC by 5 October following the end of the tax year in which you started self-employment.

The tax year runs from 6 April to 5 April. So:

If you started self-employment any time between 6 April 2025 and 5 April 2026 (the 2025/26 tax year), you must register by 5 October 2026.
If you started between 6 April 2024 and 5 April 2025, the deadline was 5 October 2025.

That said, there is no penalty for registering early, and doing so is strongly recommended. The sooner you register, the sooner you receive your Unique Taxpayer Reference (UTR) number, which you need to file your tax return and, increasingly, to verify your identity with clients and platforms.

What You Need Before You Start

Before you begin the online registration, gather the following information:

Personal Details

Your full name
Your date of birth
Your National Insurance number (found on payslips, your P60, or a letter from HMRC or DWP)
Your current home address
Your phone number and email address

Business Details

The nature of your business (a short description of what you do, such as "graphic design" or "plumbing services")
The date you started (or plan to start) self-employment
Your business name (if different from your own name — sole traders often just trade under their own name)
Your business address (often your home address)
Your business phone number (can be the same as your personal number)

Government Gateway Account

You will need a Government Gateway user ID and password to register online. If you do not already have one (for example, from previous dealings with HMRC), you will need to create one during the process.

Step-by-Step: Registering Online

Here is the process for registering as self-employed with HMRC using their online service.

Step 1: Go to the HMRC Registration Page

Visit GOV.UK and search for "register as self-employed" or go directly to the Self Assessment registration page. The service you need is called "Register for Self Assessment."

Step 2: Sign In or Create a Government Gateway Account

If you already have a Government Gateway account, sign in. If not, select the option to create a new account. You will need to verify your identity, which may involve answering security questions or receiving a code by text or post.

Step 3: Select the Correct Registration Type

You will be asked why you need to file a Self Assessment return. Select "You are self-employed" or "You are a sole trader." If you are registering as a partner in a business partnership, there is a separate option for that.

Step 4: Enter Your Personal Details

Fill in your name, date of birth, National Insurance number, and contact details. Make sure these match the information HMRC already holds for you (from employment records, for example).

Step 5: Enter Your Business Details

Provide:

Business name — If you trade under your own name, enter that. If you have a trading name (for example, "Smith Plumbing"), enter it here.
Business type — Select "sole trader."
Business description — A short phrase describing your trade. HMRC uses Standard Industrial Classification (SIC) codes, and the online form will guide you to select the closest match.
Business start date — The date you started (or intend to start) trading. This is important because it determines your first tax year of trading and your registration deadline.
Business address — If you work from home, this will be your home address.

Step 6: Confirm Your National Insurance Obligations

The form may ask about your National Insurance status. As a self-employed person, you will be liable for:

Class 2 NI — A flat weekly rate that counts towards your state pension
Class 4 NI — A percentage of your profits above a certain threshold

You do not need to calculate these now. HMRC will work out what you owe when you file your tax return.

Step 7: Submit Your Registration

Review all the information and submit. You will receive an on-screen confirmation and should receive an email confirmation if you provided an email address.

Step 8: Wait for Your UTR Number

After registering, HMRC will send you a Unique Taxpayer Reference (UTR) number by post. This is a 10-digit number that identifies you for Self Assessment purposes. It typically arrives within 10 working days, though it can sometimes take longer.

Keep this number safe. You will need it to:

File your Self Assessment tax return
Set up your online Self Assessment account
Verify your identity with some clients, platforms, and mortgage lenders
Register for the Construction Industry Scheme (CIS) if applicable

Step 9: Set Up Your Online Self Assessment Account

Once you have your UTR, you can enrol for HMRC's online Self Assessment service. This lets you file your tax return online, view your tax position, and manage your payments. You will need your UTR and your Government Gateway login.

HMRC will send you an activation code by post, which you use to complete the enrolment. This adds another few days to the timeline, so factor it in.

The CYF Form: Registering by Post

While online registration is the quickest method, you can also register by post using form CWF1 (sometimes informally called the CYF form). You can download this from GOV.UK or request it by calling HMRC.

The form asks for the same information as the online process. Fill it in, sign it, and send it to the address on the form. Processing takes longer by post — typically four to six weeks — so online is almost always the better option.

You might use the paper form if you have difficulty accessing online services or if you are registering on behalf of someone else.

Penalties for Late Registration

If you miss the 5 October deadline, HMRC may charge a penalty for "failure to notify." The penalty depends on the circumstances:

If you come forward voluntarily and the delay is not deliberate, HMRC may not charge a penalty at all, especially if no tax is owed.
If HMRC discovers you should have registered, penalties can range from 10% to 30% of the tax due for a non-deliberate failure.
If the failure is deliberate, penalties increase to between 20% and 70% of the tax due.
If it is deliberate and concealed, penalties can reach 100% of the tax due.

On top of penalties, HMRC charges interest on any tax paid late. The best way to avoid all of this is simply to register as soon as you start trading.

What Happens After Registration?

Once registered, you are in the Self Assessment system. Your main obligation is to file a Self Assessment tax return each year by 31 January following the end of the tax year. For the 2025/26 tax year, the filing deadline is 31 January 2027.

You will also need to:

Keep records of all business income and expenses for at least five years
Pay any income tax and National Insurance due by 31 January (and potentially make payments on account in January and July)
File quarterly updates under Making Tax Digital if your income exceeds the relevant threshold from April 2026 onwards

Get Set Up Properly from the Start

Registering with HMRC is just the beginning. The sooner you set up proper bookkeeping, the easier everything else becomes — from tracking expenses to filing your return to knowing how much tax to set aside.

Accounted is designed for exactly this moment. Once you have registered, connect your bank account and let Penny, our AI bookkeeper, start categorising your transactions from day one. You will build clean, organised records from the start, so your first Self Assessment return is straightforward rather than stressful. Start your free trial of Accounted today and get your self-employed finances on the right track from the very beginning.

More on Industry Guides

Industry Guides