Sole Trader vs Limited Company: Tax, Liability & When to Switch

Summary

The decision to incorporate as a limited company is one of the most significant business decisions a tradesperson makes. It is not primarily a tax decision — it is a business structure decision with tax implications. Understanding both dimensions helps you make the right choice at the right time, rather than being driven by a single factor.

Limited companies offer tax advantages at higher income levels, but they come with substantially more administrative overhead, stricter compliance requirements, and ongoing accountancy costs. A company director has legal duties under the Companies Act 2006 that a sole trader does not. Getting this decision wrong — incorporating too early, or staying as a sole trader too long — costs money in either unnecessary costs or unnecessarily high tax.

The landscape has also changed significantly in recent years. Changes to dividend tax rates, the closure of some avoidance strategies (such as IR35 in the public and private sector), and the introduction of the domestic reverse charge for VAT in construction have all changed the calculus. Advice from a qualified accountant who works with tradespeople is strongly recommended before making this decision.

Key Facts

• Corporation tax rate — small profits (under £50,000) — 19% [verify current rate]
• Corporation tax rate — main rate (over £250,000) — 25% [verify current rate]
• Marginal relief — tapered rate applies to profits between £50,000 and £250,000 [verify]
• Director salary (tax efficient level) — typically set at the NI Lower Earnings Limit or Primary Threshold (~£12,570/year) to maintain NI record without paying significant NI [verify current optimal level with accountant]
• Dividends — taxed at 8.75% (basic rate), 33.75% (higher rate), 39.35% (additional rate) in the hands of the director/shareholder [verify current dividend tax rates]
• Dividend allowance — £500/year tax-free dividends (2025/26) [verify current allowance]
• Sole trader NI — Class 4: 6%/2% on profits above the Lower Profits Limit [verify]
• Additional accountancy cost — limited company accounts and tax return typically £800–£2,500/year more than sole trader accounts
• Companies House filing — annual confirmation statement (£13 or £34 online/paper [verify current fee]) + annual accounts
• IR35 (off-payroll working) — applies if you contract through a limited company but work like an employee; medium/large private sector clients and public sector clients must assess; if caught by IR35, tax advantages are largely eliminated
• Limited liability — company assets separate from personal assets; personal liability for debts limited in most cases (not if personal guarantees given)
• VAT domestic reverse charge — applies to construction subcontractors in the VAT chain; cash flow implications regardless of structure

Quick Reference Table

Detailed Guidance

How the Tax Saving Works

The fundamental tax advantage of a limited company at higher income levels comes from the salary/dividend split:

As a sole trader earning £60,000 profit:

• Personal allowance: £12,570 (0% tax)
• Basic rate band (£12,571–£50,270): 20% income tax + 6% Class 4 NI = 26%
• Higher rate band (£50,271–£60,000): 40% income tax + 2% Class 4 NI = 42%
• Approximate total tax + NI on £60,000 profit: ~£16,800

As a director/shareholder of a limited company earning the same £60,000:

• Company profit: £60,000 minus director salary (e.g. £12,570)
• Pre-tax profit: £47,430
• Corporation tax at 25% (simplified): ~£11,858
• After-tax profit available as dividends: ~£35,572
• Director's dividend tax (above £500 allowance, basic rate 8.75%): ~£3,090
• Director's salary income tax: £0 (within personal allowance)
• Approximate total tax: £11,858 + £3,090 = ~£14,948

Saving: approximately £1,850/year in this simplified example — but accountancy costs increase by perhaps £1,000–£1,500, so the net benefit is marginal at this income level. The benefit grows significantly above £80,000.

Note: this is a simplification. Actual figures depend on whether the company employs others, personal pension contributions, business expenses, and other factors. Always model this with an accountant.

The Tipping Point: When to Incorporate

Most accountants who work with tradespeople suggest incorporating when profits consistently reach £40,000–£50,000/year. Below this:

• The tax saving is often less than the additional accountancy cost
• The administrative burden adds significant time
• The flexibility of sole trader status (simpler expenses, easier wind-down) has real value

Above £80,000 profit, the advantage is substantial and incorporation is almost always the right decision from a tax perspective.

Other reasons to incorporate (regardless of tax):

• Limited liability protection (if you work on high-value projects)
• Tendering for contracts that require limited company status
• Bringing in a partner or investor
• Building a business to sell
• Separating personal and business finances for lending purposes

Setting Up a Limited Company

1. Choose a company name — check availability at Companies House (free search online)
2. Incorporate — via Companies House web service (£12 online, confirmed same day) or via a formation agent (£30–£100 for additional services)
3. Register for Corporation Tax — must be done within 3 months of trading; HMRC will contact you when you register at Companies House
4. Open a business bank account — required for a limited company; personal account cannot be used
5. Register for VAT — if turnover exceeds threshold; consider if advantageous below threshold
6. Register for CIS — if in construction; company registers separately from any prior sole trader registration
7. Appoint accountant — strongly recommended; limited company accounts are more complex than sole trader

Pension Contributions via a Limited Company

One of the most tax-efficient benefits of a limited company for trades business owners is pension contributions. Employer pension contributions made by the company:

• Are a business expense (reduce corporation tax)
• Do not attract National Insurance (unlike salary)
• Grow in the pension fund free of income tax and CGT

This means a £10,000 employer pension contribution from a limited company costs significantly less in effective tax terms than the equivalent income taken as salary. For trades business owners approaching retirement age, this can be a substantial benefit.

IR35 — Key Risk

IR35 (off-payroll working rules) can eliminate most of the tax advantage of operating through a limited company. If you provide services through your company to a client who controls how and when you work (like an employee), HMRC may argue you should be taxed as an employee.

For trades subcontractors working for contractors:

• Small contractors — IR35 responsibility sits with you as the worker; you must assess whether IR35 applies
• Medium and large contractors — they must assess your status and may impose employment contracts

Indicators that IR35 applies: working alongside employees doing the same job, unable to send a substitute, one client representing 90%+ of revenue, client controls your working hours, you don't take financial risk.

If IR35 applies, income is treated as employment income and the tax advantage disappears. Take professional advice if you are unsure.

What Staying Sole Trader Gets Right

Despite the focus on limited company benefits, sole trader status has genuine advantages:

• Simplicity — one tax return, simpler record-keeping
• Flexibility — drawing money from the business is immediate, not constrained by dividend decisions
• Lower costs — accountancy and compliance overhead is significantly less
• VAT flat rate scheme — available to sole traders and companies, but simpler as a sole trader
• Loss relief — sole traders can offset trading losses against other income in the year of loss (useful in start-up or difficult years)

Frequently Asked Questions

My accountant says I should incorporate at £30,000 profit — is that right?

It depends on the specifics. At £30,000 profit, the tax saving from incorporating is modest (perhaps £500–£800/year before accountancy costs). If accountancy fees increase by £1,000–£1,500, you may be worse off. Ask your accountant to provide a specific calculation for your circumstances, including the impact on pension contributions, VAT position, and CIS registration. If they can't or won't show the numbers, seek a second opinion.

Can I use a limited company to pay for my van and tools tax-free?

The company can own the van and claim capital allowances. Van running costs are company expenses. However, if you use the van for any personal journeys, there may be a benefit-in-kind tax charge (P11D). HMRC is strict about van benefits for directors. Tools and equipment bought through the company are fully deductible as capital allowances. None of this is "tax-free" — it is tax-deductible — but the effective rate is lower than the personal income tax + NI you would otherwise pay.

Can I employ my spouse or partner through the company?

Yes, if they genuinely work in the business. Salary to a spouse is deductible for corporation tax, and if it keeps them within the basic rate band, the overall household tax bill reduces. However, the salary must reflect genuine work done — HMRC challenges artificial arrangements where a spouse is "employed" at a high salary but does little. Typical genuine roles: bookkeeping, admin, quote preparation, customer calls. Documented hours and a reasonable market rate are essential.

What happens to CIS registration when I incorporate?

Your sole trader CIS registration does not transfer to your company. The company must register separately as a CIS subcontractor (and as a contractor if it pays subcontractors). HMRC requires a new application for gross payment status for the company. Plan for a period of 20% or 30% CIS deductions while the new company establishes its record.

Can I easily wind down a limited company if I decide it's not working?

It is more complex than simply stopping self-employment as a sole trader. A solvent company can be struck off (voluntary dissolution) or put into members' voluntary liquidation. Struck off companies with less than £25,000 in assets can distribute the cash informally before dissolution; above that, a formal MVL is needed to benefit from Entrepreneur's Relief / Business Asset Disposal Relief on the proceeds. Accounting and legal fees apply. This is another reason not to incorporate prematurely.

Regulations & Standards

• Companies Act 2006 — director duties, filing requirements, company law

• Corporation Tax Act 2010 — corporation tax rates and relief

• Income Tax (Earnings and Pensions) Act 2003 — PAYE, IR35, employment income rules

• Finance Act 2004 (as amended) — IR35 off-payroll working rules

• Value Added Tax Act 1994 — VAT on company supplies

• GOV.UK — Set up a limited company — Official incorporation process

• HMRC — Corporation Tax — Rates, returns, and payment

• ICAEW — IR35 guidance — Professional guidance on off-payroll working

• Federation of Master Builders — Business guides — Practical business advice for builders

• self employment tax — Sole trader tax obligations in detail

• vat for trades — VAT considerations including domestic reverse charge

• public liability — Insurance requirements that change with company structure