Sole trader or limited company: which to choose for a UK side income
Somewhere between your first side income pound and your first serious profit, a question appears: sole trader or limited company? It is one of the most common decisions professionals face as a parallel income grows, and it is also one of the most over-thought. People agonise over it far too early, or copy what a friend did without checking whether their situation matches.
The truth is that the right answer changes as your profit changes. For a small, growing side income, the simple option is usually the correct one. As profit climbs, the maths and the reasons can shift. This guide gives you the framework to decide for yourself, with the current figures that matter.
Whichever structure you pick
Free PDF: The Second Income Tax Pack 2026/27
The £1,000 rule, every 2026/27 deadline, what to set aside and how to report it.
The short answer
Most side incomes should start as a sole trader. A limited company tends to earn its extra admin only once profit is consistently higher.
Sole trader is simpler and often just as tax-efficient at lower profit. A limited company adds liability protection and tax-planning options, at the cost of more paperwork and public disclosure.
What this article covers
Sole trader vs limited company at a glance
The core difference is legal. As a sole trader, you and your business are the same legal person. As a limited company, the business is a separate legal entity that you own and direct. Almost every practical difference flows from that one distinction.
| Dimension | Sole trader | Limited company |
|---|---|---|
| Setup | Free and simple with HMRC | Register at Companies House |
| Liability | Unlimited, personal | Limited to the company |
| Tax on profit | Income tax and Class 4 NI | Corporation tax, then tax on what you draw |
| Admin | Lower, a Self Assessment return | Higher, annual accounts and filings |
| Privacy | Details stay private | Company details are public |
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Get the free tax pack →How each one is taxed
As a sole trader, every pound of profit is taxed as your personal income in the year you earn it, through Self Assessment. It stacks on top of your salary, so it is taxed at your marginal income tax rate, plus Class 4 National Insurance at 6% on profits between £12,570 and £50,270, and 2% above that.
A limited company works in two layers. The company first pays corporation tax on its profit. You then pay personal tax on whatever you withdraw, usually as a small salary plus dividends. That two-layer system is where the tax planning happens, and where a company can become more efficient at higher profit.
Corporation tax for 2026/27
After corporation tax, dividends you draw are taxed at their own rates, above a £500 dividend allowance. Those dividend rates are lower than income tax rates on the same money, which is the heart of the company advantage, but they have changed recently, so confirm the current figures on GOV.UK before you plan around them. The dividend allowance has also shrunk in recent years, which has narrowed the gain for lower-profit companies.
When incorporating starts to pay
Rates alone do not decide this. What matters is your profit level and how much of it you need to take personally. Below roughly £30,000 to £50,000 of annual profit, the tax difference is often small, and can even favour the sole trader once you account for the extra accountancy and filing costs of a company. Above that range, the limited company route more commonly delivers a clear saving, and the gap tends to widen as profit grows.
"Do not incorporate because it sounds more serious. Incorporate when the numbers, the liability, or the credibility actually call for it. Until then, simple wins."
These are general guidelines, not a rule, because the exact tipping point depends on your circumstances, how much profit you draw versus retain, and your accountancy costs. The one reliable move is to model your own numbers each year rather than assume last year's answer still holds.
The non-tax reasons that matter
Tax gets the attention, but three non-tax factors often decide the question on their own.
What it means for Making Tax Digital
Your structure also affects how you report. Sole traders with qualifying income above the Making Tax Digital thresholds move to digital records and quarterly updates, starting with income over £50,000 from April 2026. A limited company director drawing salary and dividends does not report that personal income through the same system, although the company carries its own corporation tax obligations. This is a growing factor in the decision, and worth weighing alongside the tax maths.
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Take the assessment →How to make the decision
The structure question is not a test of ambition. It is a practical choice that should follow your numbers, your risk, and your clients, in that order. Start simple, keep clean records, and let the decision update as your side income grows into something larger.
Related reading
- →Making Tax Digital for income tax: what a UK side income needs to know
- →How employed and self-employed tax work together in the UK
- →Second income vs pay rise: the tax maths nobody shows you
- →How to make a reversible bet: de-risking your first income experiment
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This is general information rather than tax or legal advice, and the rates and thresholds can change, so confirm the current position on GOV.UK or with an accountant before you decide. But the framework is durable: simple until the numbers say otherwise.
Build first. Leave second. Choose third. Start with the assessment →