Every year, thousands of UK business owners ask the same question: should I stay a sole trader and pay Income Tax, or incorporate and pay Corporation Tax instead? It sounds like an accounting technicality, but the answer can be worth thousands of pounds annually. The right structure depends on your profits, how you draw income, your personal circumstances, and your long-term plans. There is no universal correct answer — but there is almost certainly a better answer for you. This guide cuts through the jargon and gives you the facts you need to make an informed choice.
How Income Tax Works for Sole Traders
As a sole trader, your business profits are treated as your personal income. HMRC taxes them through Self Assessment alongside any other earnings you have. For the 2024/25 tax year, the rates in England and Wales are:
- Personal Allowance: £12,570 — taxed at 0%
- Basic rate: £12,571–£50,270 — taxed at 20%
- Higher rate: £50,271–£125,140 — taxed at 40%
- Additional rate: Above £125,140 — taxed at 45%
On top of Income Tax, sole traders also pay Class 4 National Insurance Contributions (NICs) at 6% on profits between £12,570 and £50,270, and 2% above that. Class 2 NICs, formerly a flat weekly charge, were effectively abolished for most sole traders from April 2024. Even so, the combined Income Tax and NIC burden at higher profit levels is substantial. A sole trader earning £80,000 in profit faces an effective marginal rate of 42% — that is 40% Income Tax plus 2% Class 4 NICs — on every pound above £50,270.
The simplicity of the sole trader model is genuine. There is no Companies House filing, no corporation tax return, and no requirement to publish accounts. But simplicity has a price when profits climb.
How Corporation Tax Works for Limited Companies
A limited company is a separate legal entity. It pays Corporation Tax on its profits, not Income Tax. Following changes introduced in April 2023, the rate is no longer a flat 19%. The current structure is:
- Small profits rate: 19% on profits up to £50,000
- Marginal relief: Applies to profits between £50,000 and £250,000
- Main rate: 25% on profits above £250,000
For a company making £60,000 profit, marginal relief means the effective Corporation Tax rate sits somewhere between 19% and 25% — meaningfully lower than the 40%+ that a sole trader at the same profit level would pay.
The key distinction, however, is that Corporation Tax is paid on company profits before any money reaches you personally. When you extract money from the company — as salary, dividends, or both — that income is taxed again at personal rates. The critical question is therefore not just "which tax is lower?" but "how much of the profit do I actually need to live on, and how much can I leave in the company?"
The Classic Director Strategy: Salary Plus Dividends
Most owner-managed limited companies use a well-established extraction strategy to minimise the overall tax burden. The director pays themselves a small salary — typically set at the National Insurance Secondary Threshold (£9,100 in 2024/25) or the Primary Threshold (£12,570) — and takes additional income as dividends.
Why does this work? Salary is deductible against Corporation Tax, reducing the company's taxable profit. Dividends are paid from post-tax profits and taxed at lower rates than salary above the basic rate band:
- Dividend allowance: £500 (2024/25) — taxed at 0%
- Basic rate dividends: 8.75%
- Higher rate dividends: 33.75%
- Additional rate dividends: 39.35%
Consider a practical example. Sarah runs a marketing consultancy generating £90,000 in profit. As a sole trader, she would pay roughly £27,000 in Income Tax and NICs. As a director of her own limited company, drawing a £12,570 salary and the remainder as dividends, her combined personal and corporate tax bill could fall to approximately £22,000 — a saving of around £5,000. The exact figure depends on her personal circumstances, so she should always verify with a qualified accountant.
This is where a platform like BizHub365 proves genuinely useful. Its built-in payroll module handles RTI submissions to HMRC for director salaries, while the dividend management tools keep your records clean and audit-ready — removing the administrative headache from what can otherwise be a fiddly process.
When Incorporation May Not Be Worth It
Incorporation is not a free lunch. Before you rush to Companies House, consider the following costs and complications:
- Accountancy fees: A limited company requires a full set of statutory accounts, a Corporation Tax return (CT600), and Companies House filings. Expect to pay £500–£1,500 more per year in accountancy costs compared to a sole trader return.
- Administrative burden: Confirmation statements, director duties, and the requirement to maintain a registered office all add time and complexity.
- Loss of simplicity: Mixing personal and company finances becomes a more serious issue. Overdrawn director's loan accounts, for instance, can trigger unexpected tax charges under Section 455 of the Corporation Tax Act 2010.
- Lower profits: If your annual profit is below roughly £30,000–£35,000, the tax saving from incorporation rarely outweighs the extra costs. The National Insurance saving on dividends versus salary only becomes significant above that threshold.
A plumber trading as a sole trader on £28,000 profit is likely better off keeping things simple. A software contractor billing £120,000 per year almost certainly benefits from a limited company structure — though IR35 rules may affect that calculation significantly if they work through a Personal Service Company.
IR35 and the Self-Employed: A Word of Caution
If you operate as a contractor through your own limited company, HMRC's IR35 legislation is impossible to ignore. Introduced to tackle what HMRC calls "disguised employment," IR35 means that if your working arrangements resemble employment — even if you invoice through a company — your income may be taxed as if you were an employee. Since the off-payroll working rules were extended to the private sector in April 2021, the determination of IR35 status now typically sits with the end client, not the contractor.
If you are caught inside IR35, the Corporation Tax versus Income Tax comparison largely collapses: your take-home pay is calculated as though you are an employee, stripping away most of the dividend extraction benefits. Always seek specialist advice if contracting is your primary business model.
Making the Right Decision for Your Business
There is no single threshold at which incorporation automatically becomes right. The decision depends on:
- Your annual profit level and how much of it you need to draw personally
- Whether you have other income sources that affect your tax bands
- Your appetite for administrative complexity
- Your long-term plans — selling the business, bringing in investors, or employing staff
- Whether IR35 applies to your working arrangements
As a general rule of thumb, many accountants suggest that incorporation becomes worth considering once net profit consistently exceeds £35,000–£40,000 per year, provided the additional administrative costs are factored in. Below that, the savings are marginal at best.
Whichever structure you choose, keeping your financial records organised year-round makes a material difference at Self Assessment or Corporation Tax time. BizHub365 supports both sole traders and limited companies — covering MTD-compliant VAT submissions, expense tracking, and cash flow forecasting — so you always have a clear picture of where your business stands, regardless of which tax regime you operate under.
Conclusion
Corporation Tax and Income Tax are not simply different labels for the same thing — they represent fundamentally different relationships between you, your business, and HMRC. For many UK business owners, the limited company route unlocks genuine tax efficiency once profits reach a meaningful level. For others, the simplicity and lower overhead of the sole trader model wins out. The right answer starts with honest numbers: know your profit, know your drawings, and take qualified advice. Get those foundations right, and the tax structure question becomes far easier to answer.