Limited Company vs Sole Trader: Tax Differences (Plain English Guide)

Choosing between operating as a sole trader or a limited company is one of the most common decisions UK business owners face. The tax implications are significant — and understanding them can save you thousands of pounds a year.

This guide compares the two structures side by side, focusing purely on the tax differences.

The Fundamental Difference

Sole traders and their business are the same legal entity. You report business profits on your personal Self Assessment tax return and pay income tax and National Insurance on those profits.

Limited companies are separate legal entities. The company pays corporation tax on its profits. You, as the director, then pay personal tax on any money you take out (salary, dividends, or both).

This separation is what creates the tax planning opportunities — and the complexity.

Tax Comparison at a Glance

How Sole Traders Are Taxed

As a sole trader, your business profit is taxed as personal income:

Income Tax Rates (2024/25)

National Insurance Contributions (NICs)

Sole traders pay:

• Class 2 NICs: £3.45 per week (if profits above £12,570)
• Class 4 NICs: 6% on profits between £12,570 and £50,270, plus 2% on profits above £50,270

Example: Sole Trader with £50,000 Profit

Effective rate: 19.8%

How Limited Company Directors Are Taxed

With a limited company, taxation happens at two levels:

Level 1: Corporation Tax on Company Profits

The company pays corporation tax on its taxable profits:

• 19% on profits up to £50,000
• 25% on profits over £250,000
• Marginal relief for profits between £50,000 and £250,000

Level 2: Personal Tax on Money You Take Out

Most directors use a salary + dividends strategy:

Salary: Typically set at the NIC threshold (around £12,570) to:

• Use the personal allowance (0% income tax)
• Minimise National Insurance
• Create a deductible expense for the company

Dividends: The remaining profit is distributed as dividends:

Example: Limited Company with £50,000 Profit

Company level:

Personal level:

Combined total tax: £7,112 + £2,609 = £9,721

Effective rate: 19.4%

Side-by-Side Comparison at Different Profit Levels

Key takeaway: The tax saving from operating as a limited company generally increases as profits rise. At lower profit levels, the difference is small and may be offset by the additional administration costs.

Filing Obligations Compared

Sole Trader Filing

• Self Assessment tax return (SA100) — due 31 January following the tax year
• Payment on account — two advance payments in January and July
• No requirement to file accounts publicly
• Simpler bookkeeping requirements

Limited Company Filing

• CT600 corporation tax return — due 12 months after accounting period end
• Annual accounts at Companies House — due 9 months after accounting period end
• Corporation tax payment — due 9 months and 1 day after accounting period end
• Confirmation Statement — annual filing at Companies House
• Personal Self Assessment — if you receive salary and/or dividends
• Payroll (RTI) — if you pay yourself a salary

Other Considerations

Limited Liability

A limited company provides personal liability protection. Your personal assets are generally protected from business debts. Sole traders have no such protection — personal and business assets are one and the same.

Administrative Burden

Limited companies require more administration:

• Maintaining statutory registers
• Filing annual confirmation statements
• Running payroll
• Preparing and filing annual accounts
• Potential accountancy fees (or using software like SimpleCompanyTax)

Pension Contributions

Both structures allow tax-efficient pension contributions, but limited companies can make employer contributions which are deductible as a business expense and don't attract NICs.

IR35 and Off-Payroll Rules

If you provide services through a limited company, IR35 legislation may apply. If HMRC deems you to be a "disguised employee," the tax advantages of operating through a limited company may be lost.

When Should You Switch from Sole Trader to Limited Company?

Consider incorporating when:

• Your profits consistently exceed £30,000-£40,000 per year
• You want limited liability protection
• You want to reinvest profits in the business (corporation tax is lower than income tax)
• Clients or contracts require you to operate as a limited company

Stay as a sole trader if:

• Your profits are modest (under £30,000)
• You value simplicity over tax efficiency
• You don't need limited liability protection
• You have no plans to take on external investment

Summary

The key tax differences between sole traders and limited companies come down to: how profits are taxed (income tax vs corporation tax), how you extract money (all profit vs salary + dividends), and the filing obligations involved.

For most micro-entity directors with straightforward businesses, the limited company structure offers meaningful tax savings — especially as profits grow. The trade-off is additional administrative complexity, which modern software can largely eliminate.