Self-employment: registering for tax and NIC

Registration

If you have decided to work for yourself by becoming self-employed, firstly you need to make sure that you are actually going to be self-employed for tax and National Insurance contributions (NIC) purposes and that you are not in fact an employee instead. Have a look at our page Employed, self-employed or neither to help you work it out. It is possible to have two ‘jobs’ where you are employed in one and self-employed in another.

No tax or National Insurance contributions are normally deducted from self-employed income (also known as your trading income), although there are exceptions to this:

• Subcontractors in the construction industry often have tax deducted from payments made to them under the Construction Industry Scheme (CIS) rules.
• Examination markers usually have tax deducted at the basic rate but not National Insurance contributions. 

We cover these exceptions in our Self-employment: a guide, and we also cover the CIS and self assessment on our Construction Industry Scheme (CIS) page. 

Unless you have been in self assessment before, once you have registered as self-employed with HMRC, you will be issued with a unique taxpayer reference (UTR) number. HMRC will then contact you in due course to tell you that you need to complete a self assessment tax return so you can report your self-employed income and expenses and work out any tax and National Insurance contributions due on that income. This is known as a ‘notice to file’. You will also be registered as self-employed for Class 2 National Insurance contributions purposes.

If you have been in the self assessment system in the past but are not currently in it when you register, HMRC will re-activate your old unique taxpayer reference (UTR) number rather than give you a new one.

If you already file self assessment tax returns for some other reason and you start earning self-employment income, you must still register as self-employed with HMRC (for Class 2 National Insurance contributions purposes) but you will already have a unique taxpayer reference (UTR) number. If you don’t register, for tax years up to 2023/24 HMRC may override your own self assessment to exclude liability to Class 2 National Insurance Contributions. Alternatively, if your earnings are such that you are treated as having paid Class 2 National Insurance contributions (2022/23 onwards), then your National Insurance record may not reflect that. In either case you will need to contact HMRC for your National Insurance record to be corrected.

If CIS applies to you, then you must still register as self-employed for tax and National Insurance contributions purposes and then also register separately as a subcontractor for CIS.

How to register

You can register in two different ways:

• Using your HMRC business tax account (BTA). If you do not already have a BTA you will firstly need to set up an ‘organisation’ account for HMRC’s online services for your self-employment. (This will be different to your own personal tax account if you already have one of these.) You will need government gateway log-in details to do this. If you’ve never used the government gateway before, you will firstly have to set this up and verify your identity.  Once your business tax account is set up, you register for self assessment by selecting ‘Add a tax to your account to get online access to a tax, duty or scheme.’ 
• completing this on screen form CWF1 and printing it and posting it to HMRC. There is no facility to print the form before completing it and it cannot be saved. 

If you cannot complete the online forms (for example because you don’t have a computer, or you don’t have a printer to print the forms) then you should call HMRC’s self assessment helpline and explain that you need to register for self assessment but are unable to do so online.

The registration process covers both tax and National Insurance contributions (NIC).

You need your National Insurance number to be able to register. You can find your National Insurance number on payslips, benefit letters, the HMRC app, or most other correspondence from HMRC. If you still cannot find it, then see our National Insurance numbers section. 

You also need the following information:

• name and full home address (including postcode) and the date you moved to that address
• previous address if you have moved house within the last three years
• date of birth
• contact telephone number
• contact email address
• unique taxpayer reference (UTR) if you have previously registered for self assessment
• the date the self-employment commenced
• the nature of the self-employment
• the business address (this may be the same as your home address)
• the business telephone number (this may be the same as your personal telephone/mobile number)

You can register with HMRC as soon as you have started trading, if you wish. However, if you then do not earn as much as you expect and your total gross trading income for the first tax year is less than the trading allowance, you will still need to file a tax return for that year unless HMRC agree to withdraw the requirement to file it. (You will need to contact HMRC to ask them to do this.) 

If you are already self-employed but have previously been claiming the trading allowance, so have not had to register in the past, you should complete the CWF1 form as soon as you know your income in any tax year is going to exceed £1,000. The form will ask you for the date when your trading allowance exemption ceased. 

It may be the case that you are starting self-employment in two unconnected trades (sometimes called multiple trades). For example, you might decide to start your own business as a hairdresser, but you also begin to make and sell greetings cards. In these circumstances, you would only need to register as self-employed once with HMRC, and on your self assessment tax return you provide details of your two separate businesses (hairdressing and selling greeting cards). We cover multiple trades on our page Calculating self-employed profits: multiple trades. 

If you start self-employment after being unemployed and you have been claiming benefits, you should also notify your Jobcentre Plus office. You should also notify your local authority if you claim local benefits, like council tax benefit.

Registering for self assessment if you are a partner 

If you are a partner in a partnership, you are considered to be self-employed for tax and National Insurance contributions purposes. You will therefore still need to register for self assessment, but this is done in a slightly different way, using form SA401. For information on how to complete the form and what information you will need, see GOV.UK The partnership will also need to be registered separately and this will have to be done before the individual partners can register (as you are asked for the partnership’s Unique Taxpayer Reference (UTR) when you are completing form SA401). For more information, see our guidance on partnerships. 

Time limits

For information on the deadlines for registering with HMRC, and what might happen if you miss the deadlines, see our page Registering for self assessment. 

After registration

If you have not been in self assessment before, then after you have registered with HMRC you will receive your unique taxpayer reference (UTR) number. The unique taxpayer reference is a ten-digit number which you will need when completing your tax return and whenever you contact HMRC.

Each year, shortly after 5 April, you will be notified by HMRC that you need to complete a tax return. This will either be under the self assessment system, or under the new Making Tax Digital for Income Tax regime, depending on how long you have been self-employed for and/or your level of gross income – see the Making Tax Digital for Income Tax heading below. 

You will either be sent a notice to file a tax return in the post or, if you have signed up for electronic communications via your Personal tax account you will receive a message in this account. If you are registered for HMRC’s online services (for example if you registered online), you may find that the self assessment link will redirect you to your personal tax account which will have been automatically created for you. You can find out more about online services in our Online tax accounts page.

Making Tax Digital for Income Tax

From April 2026, individuals who are self-employed, earn over the relevant income threshold, and do not qualify for an exemption, will have to follow the rules of Making Tax Digital for Income Tax. You must follow a separate sign up process to register for Making Tax Digital. However, you will not be required to follow the rules of Making Tax Digital until you have already submitted one tax return under the self assessment system. Therefore you will still need to register for self assessment, as outlined above, even if you are likely to fall within the scope of Making Tax Digital from the following tax year.

Ending self-employment

See our page Self-employment: stopping your business for what to do when your self-employment comes to an end, or if you registered as self-employed with HMRC but then due to a change of circumstances (perhaps an offer of employment), you decided not to work for yourself and never actually start trading. 

More information

Our self-employment guide is intended to supplement the material in this section. It explains the less common tax rules and contains more detailed information, including a case study showing how to prepare accounts and what to include on your 2025/26 tax return. We wrote this guide to help advisers (non-tax) who advise low-income self-employed individuals, as well as self-employed people who want more detailed information in one accessible place.

You can find more information on starting up a business on GOV.UK.

HMRC also have e-learning packages available online and run regular webinars which you can join to help you to get started when self-employed.

If you need further help from HMRC on registering for tax, you can contact the self-employment helpline.