How to Register as Self-Employed in the UK (Sole Trader Steps and Deadline)

That's the bit people miss: registering isn't a box you tick before day one. The tax year runs from 6 April to 5 April, and the deadline to register falls six months after the year you started, so you've got time. Leave it past 5 October, though, and HMRC can give you a penalty.

Here's who needs to register, the exact steps, and what happens next.

Do you need to register?

GOV.UK's sole trader page says you can start trading straight away without registering, but you must register for Self Assessment as a sole trader once your self-employed income in a tax year goes over the trading allowance. GOV.UK publishes the current allowance figure on its sole trader page. You can also choose to register earlier.

You can be a sole trader alongside a job. Being employed and self-employed at the same time is common, and the same rule applies to your self-employed side.

Your situation	What to do
You've started a side business and your income is under the trading allowance	You don't have to register yet, but you can
Your self-employed income has gone over the allowance this tax year	Register by 5 October after the tax year ends
You registered before but didn't need to send a return last year	You may need to reactivate your Self Assessment account instead
You're an agent registering a client	Use HMRC's agent route on GOV.UK

How to register, step by step

1. Go to Register for Self Assessment on GOV.UK and choose the self-employed or sole trader route.
2. Sign in to HMRC online services, or create sign-in details if you've never used them. Our HMRC app guide is handy once you're set up.
3. Answer the questions about you and your new business, including when you started trading.
4. Describe your business and give a business name if you use one. GOV.UK says you can use a trading name or your own name.
5. Submit and wait for your Unique Taxpayer Reference, the UTR, which HMRC sends once you're registered.

GOV.UK has a tool to check when you can expect a reply from HMRC if you're waiting for your UTR. If it's gone missing, here's how to find your UTR number.

What to have ready before you start

• Sign-in details for HMRC online services, or ten minutes to create them.
• The date you started trading, even if it was a small first job.
• The name you'll trade under. It can simply be your own name.
• A short description of what the business does.
• Somewhere to keep records from day one, whether that's a spreadsheet, an app or a folder of receipts.

None of this needs an accountant, though many people bring one in for the first return.

You'll need sign-in details first, so see how to set up a Government Gateway account.

The key dates

Date	What it means
6 April to 5 April	The UK tax year
5 October	Deadline to tell HMRC you need to file for the previous tax year
31 October	Deadline for paper tax returns
31 January	Deadline for online tax returns, and for what you owe

If you register after 5 October, GOV.UK says HMRC will send you a letter or email with a different filing deadline, 3 months from the date on it. The 31 January date for what you owe doesn't move.

What being a sole trader means

GOV.UK describes a sole trader as the simplest business structure to set up and keep records for. As one, you:

• work for yourself and are classed as self-employed,
• make all the business decisions,
• keep the profits after tax,
• have unlimited liability, so you're personally responsible for the business's debts.

That last point is why some people look at a limited company instead. For most people starting out, GOV.UK notes that sole trader is the usual first step.

If a limited company suits you better, my guide to registering a limited company explains how.

What happens after you register

• You'll need to send a Self Assessment tax return each year, and HMRC works out your Income Tax and National Insurance from your profits.
• You must keep records from the day you start trading, so you can work out your profit or loss.
• You may need to register for VAT if you meet the requirements, and you can register voluntarily before then.
• Depending on what you do, you may need licences or permits, for example to play music, serve food or trade in the street.

Our list of tax tips for the self-employed covers the record-keeping habits that make the first return far easier.

Common mistakes

1. Waiting for a big month before registering. The trigger is your income across the tax year, not a single month.
2. Mixing personal and business transactions, which makes records painful at return time.
3. Missing 5 October because you assumed the deadline was 31 January. That's the filing deadline, not the registration one.
4. Losing the UTR letter. Save it digitally the day it arrives.

My advice: register as soon as you know the business is real. It takes the deadline off your mind, and your UTR is often the first thing a client or platform asks for.

Frequently asked questions

How do I register as self-employed in the UK?

Register for Self Assessment on GOV.UK as a sole trader. You'll sign in to HMRC online services, give your details and start date, and HMRC sends you a UTR.

When do I need to register as self-employed?

By 5 October after the end of the tax year in which your self-employed income went over the trading allowance. You can register earlier if you like.

Can I start trading before I register?

Yes. GOV.UK says you can start trading straight away and register later, as long as you meet the 5 October deadline.

Can I be employed and self-employed at the same time?

Yes. Many people run a sole trader business alongside a job, and the same registration rules apply.

What if I register after 5 October?

You could get a penalty. HMRC will also give you a different filing deadline, 3 months from the date on its letter or email.