The simplest way to work for yourself in the UK, and the most common. Here is how sole trader status works, what you owe, and where its limits lie.
Around three in five UK businesses are sole traders, which makes it the default way Britain works for itself. The appeal is its simplicity: no company to register at Companies House, no separate accounts to file, just you, your work, and a Self Assessment return once a year. The catch sits in a single word that most people skip past when they start out: unlimited.
The defining feature of sole trader status is that there is no legal line between you and your business. The business does not exist as a separate person in law. Its income is your income, its profits are your profits, and crucially, its debts are your debts. This is what "unlimited liability" means in practice: if the business owes money it cannot pay, creditors can pursue your personal assets, including your savings and potentially your home.
That single feature is the most important thing to understand before choosing this structure. For a low-risk service business, freelance writing, tutoring, design, it rarely causes problems. For a business that takes on stock, borrowing or supplier credit, the exposure is real, which is often the moment people compare it against going limited.
You can start trading as a sole trader immediately; there is no formal setup. But you must register with HMRC for Self Assessment once your gross trading income passes £1,000 in a tax year. That £1,000 is the Trading Allowance: below it, you do not need to register or report the income at all.
The registration deadline is 5 October following the end of the tax year in which you crossed the threshold. Miss it and you risk a failure-to-notify penalty. Being a sole trader is closely tied to the broader idea of being self-employed, and the two terms are often used interchangeably, though "self-employed" is the wider category.
A sole trader pays Income Tax and National Insurance on profit, which is income minus allowable expenses, through the annual Self Assessment return. Take Marcus, a self-employed electrician with £55,000 of income and £9,000 of allowable expenses in 2025/26.
| Step | Amount |
|---|---|
| Gross income | £55,000 |
| Less allowable expenses | £9,000 |
| Net profit | £46,000 |
| Less Personal Allowance | £12,570 |
| Taxable profit | £33,430 |
| Income Tax at 20% | £6,686 |
| Class 4 NI at 6% (profit £12,570 to £46,000) | £2,006 |
| Total liability | £8,692 |
All £33,430 of taxable profit falls within the basic rate band (which runs to £50,270), so it is taxed at 20%. Note that Scottish taxpayers would use Scotland's own bands and rates, which differ, while the National Insurance figures are UK-wide. Run your own numbers with the sole trader tax calculator.
Sole trader status is brilliant until it is not. As profits rise, the tax efficiency gap with a limited company widens, because companies pay Corporation Tax on profits and let owners draw a tax-favoured mix of salary and dividends. There is also the liability issue, and the perception point: some larger clients prefer to contract with limited companies.
There is no fixed profit level at which you "must" incorporate; it depends on your circumstances, risk profile and how much profit you reinvest versus draw out. But many sole traders begin seriously weighing the switch as profits move into the higher-rate territory above £50,270. The limited company comparison calculator is the cleanest way to see where the crossover sits for you.
Sole trader is the fastest, simplest way to start, and the unlimited liability is the price you pay for that simplicity.
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