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A Guide to Setting Up As a Sole Trader in the UK

Written by Simply Accounts | Dec 17, 2025 12:30:01 PM

​Taking the leap into self-employment is an exciting step. For many, the simplest and most common way to start is by becoming a sole trader. This business structure means you, as an individual, are the business. It’s quick, straightforward and, crucially, involves minimal paperwork compared to a limited company.

However, even though it’s simple, there are essential steps you must take to ensure you are legally compliant and set up for success from day one. If you’ve searched online, how to set up a sole trader business, this article is designed to walk you through the process clearly and straightforwardly. We are here to be your trusted guide, making the process approachable, removing the stress of managing these new obligations alone.

Step 1: Telling HMRC You're In Business

The most fundamental part of setting up as a sole trader is registering with the government for tax purposes. You must officially notify HMRC (His Majesty's Revenue and Customs) that you are self-employed.

Register For Self Assessment

You need to register with HMRC for Self Assessment to pay income tax and National Insurance. This is the official mechanism through which you declare your business income and pay your taxes.

  • When to register: You must do this by the 5th of October following the end of the tax year in which you started trading. For example, if you started your business in June 2025 (in the 2025/2026 tax year), you must register by 5th October 2026.
  • The Process: The easiest way to complete how to register as a sole trader is online via the Government Gateway. You will receive your Unique Taxpayer Reference (UTR) number shortly afterwards. Keep this number safe; you will need it for all future tax returns.

Failing to register on time can result in penalties, which is the last thing you need when starting a new venture. So, marking that 5th October deadline in your calendar is the single most important administrative task you have.

Step 2: Getting Organised From Day One

Once registered, your focus shifts to the practicalities of running your business and managing your new responsibilities.

Records And Money

You must keep records of all income and expenses from day one. Good record-keeping is the bedrock of a successful sole trader business. Your Self Assessment tax return depends entirely on accurate records.

  • Income: Keep all invoices, sales receipts and records of money coming in.
  • Expenses: Keep receipts, invoices and records for all business costs. Remember, only allowable business expenses can be deducted to lower your tax bill.

It is also highly recommended that you consider business essentials like insurance and a separate bank account. A dedicated bank account keeps your business finances completely separate from your personal money, making record-keeping and tax calculation far easier.

Understanding Your Obligations

As a sole trader, you need to understand responsibilities for tax, National Insurance and pensions.

  • Income Tax: Calculated based on your profit (income minus allowable expenses).
  • National Insurance (NI): You will usually pay Class 2 and Class 4 NI contributions, which are calculated via your Self Assessment return.
  • Pensions: While not mandatory, it’s crucial to think about saving for your retirement, as you no longer have an employer enrolling you in a workplace pension scheme.

Step 3: Keeping It Simple (And Why Expertise Helps)

One of the great appeals of setting up as a sole trader is that the structure is designed to keep things simple, minimal paperwork compared to a limited company. Generally, you don't have to deal with corporation tax, formal statutory accounts or filings with Companies House, which saves you a vast amount of administrative time. However this depends on your turnover and costs. We may recommend a bookkeeping package and set of year end accounts if this would benefit your tax situation.

However, simple doesn't always mean easy. When you’re busy trying to build your business, learn a new market and find clients, managing VAT registration thresholds, allowable expenses and tax deadlines can quickly become overwhelming.

How We Can Help

That’s why we always recommend you consider seeking an accountant to reduce stress and make things easier. Here at Simply Accounts, we're not a faceless online company, our advice comes from real people who care. And our sole trader accountants can ensure you:

  • Register correctly and on time.
  • Claim every allowable expense, ensuring you are as tax efficient as possible.
  • Never miss a deadline.
  • Get proactive advice to help your business grow.

We’ll take the weight off your shoulders, giving you peace of mind that your financial house is in order. We’ll work with you to find a service that fits best, ensuring your start to self-employment is as smooth and successful as possible. Get in touch with our team today, we’re always happy to help!

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