Most people pick their business structure when they start out and never look at it again. That is a mistake. The structure you trade under directly affects your tax bill, your National Insurance, your personal liability, and — from April 2026 — your quarterly reporting obligations to HMRC.
For 2026/27, three things have changed the calculation. Mandatory Class 2 NI is gone. Making Tax Digital for Income Tax has started for sole traders earning above £50,000. And Corporation Tax stays at 19% for profits under £50,000 — still lower than what a sole trader pays in combined Income Tax and Class 4 NI on the same figure. If you are starting your first business in the UK or you have been trading for a few years and your profit is growing, this guide gives you the numbers to make the right call.
The Core Difference
Sole trader: you are the business
As a sole trader, you and your business are the same legal entity. Every penny of profit belongs to you — and every debt belongs to you too. You report income and expenses through Self Assessment each year and pay Income Tax and National Insurance on whatever is left after allowable costs.
There is no registration fee. You notify HMRC that you are self-employed, create a Self Assessment account, and keep records of your income and outgoings. Registering your business in the UK as a sole trader takes around 20 minutes online and costs nothing.
Limited company: a separate legal entity
A limited company is distinct from you as a person. It registers with Companies House, carries its own legal identity, pays Corporation Tax on its profits, and files its own accounts annually. You can be the only director and sole shareholder. The company owns its assets and owes its debts — not you personally.
The key difference is how money moves from the business to your pocket. As a director, you typically draw a low salary and take the rest as dividends. Both are taxed differently from sole trader profits. To understand the full structure before comparing tax, the guide on what a limited company is in the UK covers the legal and administrative setup in detail.
National Insurance for Self-Employed UK 2026/27
National Insurance for self-employed people works very differently from PAYE employment. And 2026/27 is simpler than previous years — because one charge has gone entirely.
Class 2 NI: what happened
Mandatory Class 2 NI was abolished from April 2024 under the National Insurance Contributions (Reduction in Rates) Act 2023. Before that, self-employed people paid a flat weekly charge. That obligation no longer exists.
For 2026/27:
- Profits above £7,105 (Small Profits Threshold): You receive Class 2 NI credits automatically. No payment. Your State Pension qualifying record is protected.
- Profits below £7,105: No automatic credit. You can pay voluntary Class 2 contributions of £3.65 per week (£189.80 for the full year) to protect your State Pension record.
That voluntary £3.65 matters. If you skip it and try to fill the gap later, voluntary Class 3 contributions cost £18.40 per week in 2026/27 — nearly five times more. Low-profit years are almost always worth plugging with voluntary Class 2.
Class 4 rates and thresholds for 2026/27
Class 4 is the main NI charge for sole traders. It comes out of your Self Assessment return — not as a separate payment throughout the year.
| Profit Band | Class 4 Rate 2026/27 |
|---|---|
| Up to £12,570 | 0% |
| £12,570 – £50,270 | 6% |
| Above £50,270 | 2% |
Worked example: On £45,000 profit, you pay Class 4 on £32,430 (£45,000 minus £12,570). At 6%, that is £1,945.80 in Class 4 NI for the year.
Class 4 does not build State Pension entitlement. Only Class 2 credits — automatic or voluntary — do that.
What limited company directors pay in NI
A limited company director drawing a salary of £12,570 — the standard approach for 2026/27 — pays:
- Employee NI (Class 1): £0. The salary sits at the Primary Threshold.
- Employer NI (Class 1): Around £478 on that salary (15% above £5,000). The Employment Allowance of £10,500 that many employers claim is not available to companies where the sole director is the only employee. This is a planning factor most comparison guides ignore.
Dividends carry no National Insurance at all. A director drawing £50,000 total (salary plus dividends) pays significantly less NI than a sole trader on the same profit. That difference is the core of the incorporation argument.
Tax Comparison at Three Real Profit Levels
All figures use 2026/27 rates. Full personal allowance (£12,570) assumed throughout. England and Wales Income Tax rates apply. No VAT registration assumed. Limited company figures use an optimal salary-plus-dividends extraction strategy.
£30,000 profit
Sole trader Income Tax at 20% on £17,430 (profit minus personal allowance) = £3,486. Class 4 NI at 6% on £17,430 = £1,045.80. Total: approximately £4,531.
Limited company Corporation Tax at 19% on £30,000 = £5,700. Director draws £12,570 salary (no Income Tax, no employee NI). Remaining funds distributed as dividends. After the £500 dividend allowance, dividend tax at 8.75% on the balance. Total combined tax burden: approximately £5,200–£5,600 — before accountancy fees of £800–£1,200/year.
Verdict at £30k: Sole trader wins. The limited company tax bill is higher at this profit level, and accountancy costs make it worse. Incorporation does not pay here.
£50,000 profit
Sole trader Income Tax: 20% on £25,130 (£12,570–£37,700) = £5,026. Plus 40% on £12,300 (£37,700–£50,000) = £4,920. Class 4 NI: 6% on £37,700 = £2,262. Plus 2% on £0 (under upper limit). Total NI: £2,262. Total: approximately £12,208.
Limited company Corporation Tax at 19% = £9,500. Director draws £12,570 salary (no personal tax). Remaining after-CT profits distributed as dividends. Dividend tax at 8.75% above the £500 allowance. Combined tax: approximately £11,500–£12,500 — broadly similar to sole trader, before accountancy fees.
Verdict at £50k: Break-even territory. On paper the numbers are close. Once accountancy costs are added, the sole trader can still come out ahead — especially if you leave no profit in the company. The limited company only wins clearly here if you do not extract all profits personally each year.
£80,000 profit
Sole trader Heavy higher-rate exposure. Income Tax at 40% kicks in on earnings above £50,270. Class 4 NI drops to 2% above the upper profits limit, but the Income Tax bill rises sharply. Total tax and NI: approximately £26,500–£28,000.
Limited company Corporation Tax at 19% (small profits rate on the first £50,000, marginal relief above that). Director draws salary at £12,570, takes dividends taxed at 8.75% instead of 40% Income Tax on the same amount. Total combined tax: approximately £20,000–£23,000 — a saving of £3,000–£6,000 per year over sole trader, even after accountancy fees.
Verdict at £80k: Limited company wins clearly. The gap between the two structures grows with profit. At this level, incorporation typically pays for itself within the first year.
Personal Liability: Why It Matters More Than Tax
Sole traders carry unlimited personal liability. If the business owes money and cannot pay, the debt is yours personally. Your savings, your car, and potentially your home are all exposed.
A limited company separates you from the business legally. The company’s debts belong to the company. As a director, you can lose what you put in as share capital — but your personal assets are generally protected, unless you have personally guaranteed loans or HMRC is pursuing director liability for misconduct or fraud.
For anyone in a sector where professional disputes, contract failures, or negligence claims are realistic possibilities, this protection often matters more than the tax saving. That said, sole traders can reduce exposure through affordable business insurance in the UK — professional indemnity and public liability cover in particular closes much of the practical gap.
Admin and Accountancy Costs
Sole traders file one Self Assessment return per year. Income Tax and Class 4 NI are calculated together. Many sole traders do this without an accountant. When they do use one, costs typically run £200–£600 per year for a straightforward return.
Limited companies carry more. You need annual accounts filed at Companies House, a Confirmation Statement, a Corporation Tax return, and a personal Self Assessment return as director. Most single-director limited companies pay an accountant £800–£1,500 per year. More complex arrangements push that figure higher.
That recurring annual cost has to be covered before the tax saving counts as an actual saving. At £50,000 profit, a £1,200 accountancy bill narrows the apparent advantage considerably. Getting the admin side right from the start matters for both structures — small business accounting tips for UK owners covers how to keep records clean and costs manageable.
Making Tax Digital from April 2026
Making Tax Digital for Income Tax (MTD ITSA) started on 6 April 2026. It affects sole traders and landlords — not limited companies, which already report Corporation Tax separately.
Phase 1 — now live (April 2026): Sole traders and landlords with qualifying gross income above £50,000 must keep digital records and submit quarterly updates to HMRC through compatible software. That is four submissions per year, plus a final end-of-year declaration — five in total.
Phase 2 — April 2027: The threshold drops to £30,000 qualifying gross income.
Phase 3 — April 2028: Extended to £20,000 (confirmed at Spring Budget 2025).
Qualifying income means total gross income from self-employment plus rental income combined — before expenses. A sole trader with £44,000 in business turnover and £8,000 in rental income has £52,000 qualifying income and falls inside Phase 1 now.
MTD adds real cost. Compatible software typically runs £10–£30 per month. Quarterly submissions have specific deadlines. Missing them triggers penalty points — four points results in a £200 fine.
Limited companies sit outside this system. Some sole traders above the £50,000 threshold are choosing to incorporate partly to remove themselves from the MTD obligation. The full requirements and compliance steps are covered in the Making Tax Digital for Income Tax guide.
IR35: When the Tax Advantage Disappears
IR35 — formally the off-payroll working rules — applies to contractors operating through a limited company whose working arrangements resemble employment. HMRC asks: if the contract were directly between you and the end client, would you be an employee?
If yes, income from that contract is taxed as employment income. The salary-and-dividends strategy that generates the limited company tax saving does not apply. Corporation Tax still runs, but the personal tax advantage is eliminated for that income.
Since April 2021, medium and large private-sector clients determine IR35 status — not the contractor. If your client decides your contract falls inside IR35, they apply PAYE directly. Your limited company wrapper provides no protection.
If your contracts are genuinely outside IR35 — multiple clients, control over how and when you work, no obligation of mutuality — the limited company structure works as intended. But if you work primarily for one client, in their premises, under their supervision, IR35 risk is real. Incorporating in that situation adds admin without adding tax savings.
When to Switch from Sole Trader to Limited Company
The profit threshold guide
- Below £40,000 profit: Sole trader is typically simpler and roughly tax-equivalent or better once accountancy costs are counted. Do not incorporate at this level for tax reasons alone.
- £40,000–£60,000 profit: The break-even zone. Incorporation may or may not save money, depending on how much you extract personally, your IR35 exposure, and whether a spouse or partner can hold shares to distribute income into a lower tax band.
- Above £60,000 profit: A limited company generally saves £1,500–£6,000+ per year after all costs. The advantage increases with profit.
Other factors beyond profit
Profit is not the only reason to incorporate. A limited company may be the right structure if:
- Clients require it — some larger organisations and public sector bodies will not contract with sole traders
- You want to protect personal assets from business liability
- You plan to bring in external investment or issue shares to employees
- You want to retain profits inside the company rather than drawing everything each year
The sole trader vs limited company comparison page covers how these non-tax factors interact with your specific situation.
Quick Comparison Table
| Sole Trader | Limited Company | |
|---|---|---|
| Legal status | You and business are one | Separate legal entity |
| Income Tax | 20% / 40% / 45% on profits | Via salary + dividends |
| Corporation Tax | None | 19% (under £50k profit) |
| Class 4 NI | 6% on £12,570–£50,270 / 2% above | Not applicable on dividends |
| Personal liability | Unlimited | Limited to share capital |
| Companies House filing | None | Annual accounts + Confirmation Statement |
| MTD from April 2026 | Yes if gross income >£50k | Not applicable |
| Accountancy cost | £200–£600/year | £800–£1,500/year |
| Tax advantage | Simpler below £40k | Saves £1,500–£6k+ above £60k |
Three Questions to Ask Before You Decide
1. What is your realistic profit for the next 12 months — not turnover, profit? Below £40,000, sole trader is almost certainly the right answer. Above £60,000, limited company is worth the switch. In between, it depends on questions two and three.
2. Do you need every pound of profit personally each year? The limited company advantage partly relies on leaving money inside the company and only drawing what you need. If you must extract everything annually, Corporation Tax reduces the gain before you even get to personal tax.
3. Is your income from a single client in a way that could attract IR35? Get a proper IR35 review before you incorporate. Incorporating and then being caught inside IR35 gives you all of the admin and none of the tax benefit.
If your profit is above £60,000, your income comes from multiple clients, and you can leave some money in the company each year, incorporation is likely the right move. If you are below £40,000 and just getting started, focus first on understanding your Self Assessment tax return obligations — and revisit the structure question when your profit grows.
Tax rules change annually. These figures apply to 2026/27 and reflect current HMRC rules. Confirm with a qualified accountant before changing your structure.
