How to register as a sole trader — and the five things nobody tells you

The registration itself is almost an anticlimax. You tell HMRC you are self-employed by registering for Self Assessment, a Unique Taxpayer Reference arrives, and that is it. Free, online, and about ten minutes of typing.

What is not an anticlimax is everything the registration sets in motion: a filing deadline, a National Insurance position, a tax bill that can land up to nineteen months after your first invoice, and a Making Tax Digital start date that most new sole traders do not know applies to them. This is the whole process, in order, with the numbers.

First, do you actually have to register?

The test is turnover, not profit. You must register for Self Assessment as a sole trader if you earned more than £1,000 from self-employment in a tax year, which runs 6 April to 5 April. That £1,000 is the trading allowance: below it you generally have nothing to report, above it you do — even if you made a loss after costs.

Two things people get wrong here. The £1,000 is measured on money coming in, before you take off any expenses, so a £4,000-turnover side business with £3,500 of costs is still over the line. And it is per tax year, not per client or per platform — everything you do for yourself is added together.

The deadline, and why "5 October" confuses everyone

You must tell HMRC by 5 October following the end of the tax year in which you started. So if you take your first payment in July 2026, that falls in the 2026/27 tax year, which ends on 5 April 2027, and your registration deadline is 5 October 2027.

Miss it and you are into failure-to-notify territory: the penalty is a percentage of the tax that was late as a result, and it is reduced substantially — often to nothing where no tax has been lost — if you come forward before HMRC contacts you. Telling them late is always cheaper than being found.

The registration itself, step by step

1. Set up a Government Gateway account if you do not have one. Use an email address you will still have in five years, and store the user ID somewhere permanent.
2. Register for Self Assessment as self-employed. HMRC asks for your National Insurance number, date of birth, home address, contact details, the date your self-employment started, the nature of your business, and your business address if it differs.
3. Wait for your Unique Taxpayer Reference. The ten-digit UTR is posted to you and it is yours for life — you will need it for every return, and contractors will ask for it if you work in construction. Allow a few weeks for it to arrive, which is exactly why you register when you start trading rather than the week before a deadline.
4. Register separately for anything else that applies. Construction Industry Scheme registration if you subcontract on building work, so deductions are taken at 20% rather than 30%. PAYE registration if you take on staff. VAT if you cross the threshold.

Naming the business

You can trade under your own name or a business name, and neither has to be registered anywhere. There are limits: you cannot use "limited", "Ltd", "LLP" or "plc" (they imply a legal structure you do not have), you cannot use offensive or sensitive words without permission, and you cannot use a name that someone else has trademarked — check the Intellectual Property Office register before you order the van livery.

One duty comes with using a business name: your own name and an address where documents can be served must appear on your invoices, letters and other business paperwork.

What the first bill actually looks like

This is the part worth reading twice, because the shape of the first payment surprises almost everyone.

Class 2 National Insurance no longer has to be paid separately: it is £3.65 a week for 2026/27 and voluntary, and profits of £7,105 or more are treated as though you had paid it, so your state pension record keeps building. Our National Insurance guide has the detail, and payments on account explained covers why that first January is so much larger than the calculation people do in their head.

The five things nobody tells you

1. Open a separate account the same week. Mixing personal and business money is the decision people most regret by year two, because untangling it costs either your evenings or your accountant's time. A free business account takes minutes to open.
2. Start the tax pot with your first payment. Move 25% of everything you receive into a separate savings pot — 20% covers the tax, and the extra 5% builds the buffer for that first payment on account. If your profit is heading over £50,270, make it 30%.
3. Claim what you spent before you registered. Costs incurred in the seven years before you started trading — a laptop, tools, a website, training that was not a new qualification — are generally treated as if you spent them on your first day of trading, so they reduce your first tax bill. Most people throw those receipts away. The expenses A–Z is worth reading before you file.
4. Sort insurance, not just tax. Public liability if you work near other people or their property, professional indemnity if you give advice, and check whether your car insurance covers business use. Clients increasingly ask for certificates before they will sign.
5. Know the three thresholds you are walking towards. £50,270 is where higher-rate tax starts. £90,000 of taxable turnover in any rolling 12 months forces VAT registration within 30 days — and it is a rolling test, not a tax-year one, which is how growing sole traders get ambushed (see the VAT threshold trap). And Making Tax Digital is next.

Making Tax Digital: check whether it already applies to you

Making Tax Digital for Income Tax replaces one annual return with digital record-keeping plus quarterly updates and a final declaration. It is being phased in by qualifying income — gross income from self-employment and property, before expenses — tested on the previous year's return:

• Over £50,000 on the 2024/25 return: in scope from 6 April 2026.
• Over £30,000 on the 2025/26 return: in scope from 6 April 2027.
• Over £20,000 on the 2026/27 return: in scope from 6 April 2028.

Because it is measured on income rather than profit, a sole trader turning over £25,000 with modest profits is in scope from April 2028. HMRC writes to you when your return puts you over a threshold. The practical consequence for someone registering today: choose bookkeeping software now rather than a shoebox, because you will need it. Our MTD guide for sole traders sets out what to do first.

Your first-week checklist

1. Confirm you are over the £1,000 trading allowance.
2. Register for Self Assessment and note your registration deadline in your calendar.
3. Open a separate business bank account.
4. Set the tax pot at 25% and automate the transfer.
5. Pick your bookkeeping software and connect it to the bank account.
6. Dig out pre-trading receipts from the last seven years.
7. Diary the 31 January and 31 July dates from the key tax dates calendar.

If limited company status is also on your mind, do the comparison before you build habits around one structure — our sole trader vs limited company guide runs the numbers both ways.

Or compress the whole list into one move: our Start package is £19 + VAT a month — FreeAgent, your Self Assessment return and a named accountant, from your first week of trading. Get started and we will handle the registration with you.