How to Register as Self-Employed in the UK — Step by Step

A lot of tradespeople go self-employed gradually — picking up a few jobs on the side before going full time. HMRC are fine with that, but they do need to know about it. Here's the process, what the deadlines are, and what happens once you're registered.

When do you need to register? You need to register for Self Assessment as self-employed by 5 October following the end of the tax year in which you started working for yourself.

The UK tax year runs 6 April to 5 April. So if you started doing self-employed work in August 2025, you're in the 2025/26 tax year and need to register by 5 October 2026.

That said, don't wait. Register as soon as you go self-employed. You need your UTR number (which takes up to 10 days to arrive) before you can register for CIS or file any returns. Starting the clock early means nothing is rushed later.

What you need before you start Before registering, have ready: Your National Insurance number Your date of birth Your home address Your email address (for your Government Gateway account) The date you started self-employment Your trade — what type of work you do Whether you're operating under your own name or a business name

The registration process — step by step

Go to gov.uk and search for "register as self-employed"
Select the option to register for Self Assessment as self-employed
Create a Government Gateway account if you don't have one — you'll need an email address and you'll set a password
Complete the registration form — your personal details, start date, trade, and how you expect to receive income
Submit

HMRC will send your Unique Taxpayer Reference (UTR) by post to your home address within 10 working days. Keep this letter — it has your UTR on it and you'll need the number repeatedly.

Setting up your Government Gateway account

Your Government Gateway account is your online access to all HMRC services — Self Assessment, CIS, VAT if applicable, your tax records. Take five minutes to set it up properly and save your login details somewhere secure.

Once your UTR arrives, link it to your Government Gateway account if it isn't already.

Registering for CIS — a separate step

If you're working as a subcontractor in construction, registering for Self Assessment gets you your UTR. Registering for CIS as a subcontractor is a separate step.

Once you have your UTR, go to your Government Gateway account, find the CIS section, and register as a CIS subcontractor. Alternatively call the CIS helpline on 0300 200 3210.

CIS registration is what drops your deduction rate from 30% to 20%. Do it as soon as you have your UTR.

Register for VAT — only if you need to

You only need to register for VAT if your turnover exceeds the VAT threshold (currently £90,000 per year) or if you choose to register voluntarily. Most sole traders starting out don't need to worry about this immediately.

What happens after registration?

You'll receive a notice to file a Self Assessment return for the relevant tax year. The first filing deadline after you register is 31 January following the end of the tax year.

In the meantime, keep records of all income received and expenses paid from the day you started. You'll need them to complete your return.

Do you need an accountant?

Not legally. But for most tradespeople, the cost of an accountant is recouped through the expenses they identify that you'd have missed, plus the time saved. Accountant fees are themselves a claimable expense.

The bottom line Registering is not complicated. It's a 20-minute process online. The thing that creates problems is leaving it too late, not having a UTR when a contractor needs it, and not keeping records from day one. Sort those three things and the rest is straightforward.