Register as self-employed: UK tradespeople

The 5 October deadline, and the UTR

HMRC's deadlines page (opens in a new tab) says you must tell HMRC by 5 October if you need a tax return for the previous year and either you have not sent a return before, or you registered before but did not need a return for 2024 to 2025. You tell them by registering for Self Assessment.

For the date written on that page now, the previous tax year started on 6 April 2025 and ended on 5 April 2026. The registration check (opens in a new tab) names the deadline for that year as 5 October 2026. If you tell HMRC after 5 October 2026, you could get a penalty.

If you register after 5 October 2026, the deadlines page says HMRC sends a letter or email with a different filing deadline. That deadline is 3 months from the date on the letter or email. The payment date does not move with it. You must still pay the tax you owe by 11:59pm on 31 January 2027. The filing dates for that return are in the Self Assessment guide.

A tax year runs from 6 April to 5 April. The 5 October you use is the one after the tax year the return is for, which is the rule on the deadlines page. For a first return covering 6 April 2025 to 5 April 2026, that date is 5 October 2026.

You get a Unique Taxpayer Reference when you register for Self Assessment. HMRC's UTR page (opens in a new tab) says it is a 10-digit number. It might just be called a tax reference. You usually get it by post around 15 days after you register. It takes longer if you live overseas. You can find it in your Personal Tax Account, in the HMRC app, or on documents HMRC has already sent, such as a notice to file a return.

HMRC's note on the newer registration service (opens in a new tab), published on 9 September 2026, says people using that service get the UTR in their online account within 72 hours, instead of waiting up to 15 days for the post. The online service is for an individual with a Personal Tax Account. An agent still uses the existing forms, including CWF1 or an SA1.

You need the UTR to file online. HMRC's filing page (opens in a new tab) says that. Do not paste a UTR, a National Insurance number, or a password into a chat tool.

Class 2 and Class 4 National Insurance

HMRC's self-employed National Insurance page (opens in a new tab) says the class you pay depends on your profits. Profit is self-employed income after expenses. Most people pay Class 2 and Class 4 through Self Assessment. You must tell HMRC when you become self-employed as a sole trader or in a partnership.

Read on 17 October 2026, that page says:

• If your profits are £7,105 or more a year, Class 2 is treated as paid. You do not pay Class 2. That still protects your National Insurance record.
• If your profits are less than £7,105 a year, you do not have to pay anything. You can choose voluntary Class 2. The Class 2 rate for the 2026 to 2027 tax year is £3.65 a week.
• If your profits are more than £12,570 a year, you pay Class 4. For the 2026 to 2027 tax year the rate is 6% on profits over £12,570 up to £50,270, and 2% on profits over £50,270.

Those are the figures on the page. A chat tool must not swap them for another year. What comes off the income before the profit is worked out is in the allowable expenses guide.

If you work for a contractor: CIS

If you do construction work for a contractor, HMRC's CIS overview (opens in a new tab) says you should register for the Construction Industry Scheme when you are a sole trader, a company owner, or a partner. A contractor deducts 20% when you are registered. That is net payment status. The deduction is an advance payment towards tax and National Insurance. If you are not registered, the contractor deducts 30%. An employee does not register for CIS.

How to register (opens in a new tab) says the online service registers you for net payment status. You need a UTR to use it. If you do not have one, register as a new business for Self Assessment and choose "working as a subcontractor" when asked. That registers you for Self Assessment and CIS together. You also give your legal business name, a trading name if it differs, your VAT number if you have one, and the date you started trading. False information can bring a fine.

The CIS guide sets out what the percentage comes off, and what gross payment status asks for. CIS registration is not VAT registration, and it is not Making Tax Digital. Those start dates are in the Making Tax Digital guide.

A simple income and expenses log

HMRC's records guide (opens in a new tab) says a sole trader keeps records of business income and expenses. If you do not prepare accounts, you record them for each tax year, 6 April to 5 April. From the 2024 to 2025 tax year, cash basis is the default. You record money when you receive it or pay it. You opt out if you want traditional accounting.

What to keep (opens in a new tab) includes all sales and income, all business expenses, and proof such as receipts and bank statements. The records have to be accurate, and you have to be able to identify the business transactions. You keep them (opens in a new tab) for at least 5 years after the 31 January submission deadline for that tax year.

Turn these notes into a simple income and expenses log for a UK sole trader. UK English. Use pounds. One line per item. Do not invent amounts, dates, customers, or suppliers. If a figure or a date is missing, write MISSING. Do not say a cost is allowable. Do not add tax or National Insurance.

Tax year (6 April to 5 April):
Accounting method I use, or "not stated": cash basis or traditional
Income notes:
Expense notes:
[paste only lines you are happy to share]

Do not paste a Unique Taxpayer Reference, a National Insurance number, a bank account number, or a card number. Check every line against the invoice or the receipt.

List the registration facts I have already collected. UK English. Do not tell me I am registered. Do not invent a UTR, a deadline, or a National Insurance figure. If a line is blank, write NOT SUPPLIED.

Date I started trading, or "not started":
Tax year that start date sits in:
Whether I have registered for Self Assessment: yes, no, or not sure
UTR: "I have it" or "I do not have it". Do not ask me to paste the number.
Whether I work for a contractor under CIS: yes, no, or not sure

If the draft has written 5 October 2026 and you did not type the tax year, delete that line. Check the deadlines page (opens in a new tab) for the year you started.