If you're asking how to switch from sole trader to limited company, you're likely past the point of wondering whether it's the right move. Your turnover has grown. You're paying more tax than feels fair. Or a client has told you they'd rather contract with a limited company. Whatever the trigger, the switch itself is straightforward. The decisions around when and how to do it cleanly are where most people trip up.

This guide covers the practical steps for 2025/26. We'll walk through incorporation, what happens to your existing contracts, how to handle VAT, and the tax implications of moving from sole trader to limited company. We are ICAEW qualified accountants and work with UK businesses across every sector. The advice below is general. Your specific numbers may point to a different timing or structure. Always run the figures past a qualified accountant before making the leap.

Why Switch From Sole Trader To Limited Company?

The most common reason is tax efficiency. Once your profits exceed roughly £40,000 to £50,000, a limited company structure typically leaves more money in your pocket after tax than remaining a sole trader. That gap widens as profits increase.

Take a freelance consultant in Manchester turning over £80,000 with £20,000 of expenses. As a sole trader, you'd pay income tax and Class 2 and Class 4 National Insurance on the £60,000 profit. For 2025/26, that works out to roughly £14,720 in combined tax and NIC. Through a limited company, paying yourself a salary of £12,570 and dividends of £42,430, your total tax (corporation tax, income tax, dividend tax, employer NI) comes to around £11,400. That is a saving of over £3,300.

Other reasons include:

  • Limited liability. Your personal assets are separate from the company's debts. If something goes wrong, you don't lose your house.
  • Professional credibility. Some clients and larger contracts require you to trade as a limited company.
  • IR35 requirements. If you contract through an intermediary, many clients now insist on limited company status.
  • Retained profits. You can leave profits in the company and pay tax on them later when you extract them as dividends.

Step 1: Check Whether Incorporation Is Right For You

Not every sole trader should incorporate. If your profits are below £30,000, the costs of running a limited company (accountancy fees, Companies House filings, payroll software) can outweigh the tax savings. You also lose the simplicity of sole trader accounting.

For a husband-and-wife Ltd company running a Birmingham café, the decision often comes down to whether both partners are actively involved. If only one works in the business, a sole trader structure may still be more efficient below certain profit levels.

Use our incorporation calculator to compare your current tax position as a sole trader against what you'd pay through a limited company. The calculator factors in corporation tax rates, dividend tax, and employer NI for 2025/26.

Step 2: Incorporate Your Limited Company

You register a limited company through Companies House. The process is online and costs £50. You'll need:

  • A company name (check it's not already taken or too similar to an existing name)
  • A registered office address (this goes on the public register)
  • At least one director (you)
  • At least one shareholder (typically you, possibly your spouse or business partner)
  • A person with significant control (PSC) (you, if you own more than 25% of shares)
  • A Standard Industrial Classification (SIC) code that matches your trade

Most people choose to issue 100 ordinary shares. You can issue different classes of shares (alphabet shares) if you want flexibility on dividends later. This matters if you plan to bring in a co-director or pay dividends to a spouse.

Once registered, you'll receive:

  • A Certificate of Incorporation
  • A company number (you'll use this on invoices, contracts, and tax returns)
  • Your company authentication code (keep this safe, you need it for filing)

You must then register the company for Corporation Tax with HMRC. You have three months from the date of incorporation to do this. HMRC will send you a CT41G form (or you can register online). They'll set up a corporation tax reference and tell you when your first return is due.

Step 3: Register For PAYE and Payroll

As a limited company director, you must register for PAYE. Even if you're the only employee, you need to run payroll. You can do this yourself using software like Xero, FreeAgent, or BrightPay, or your accountant can handle it.

Most directors pay themselves a salary up to the personal allowance (£12,570 for 2025/26) and take the rest as dividends. The salary is a tax-deductible expense for the company. Dividends are paid from post-tax profits and attract lower tax rates than salary.

If your salary is above the secondary threshold (£9,100), the company pays employer NI at 13.8%. You can claim Employment Allowance (up to £10,500) if you're eligible, which often covers the NI cost for a single director.

Read more in our guide on director pay and dividends.

Step 4: Transfer Your Existing Contracts and Assets

This is where the switch gets practical. As a sole trader, your contracts are in your personal name. Your new limited company is a separate legal entity. You cannot simply start invoicing through the company unless the client agrees.

Contact each client and explain the change. Most will issue a new contract or a deed of novation that transfers the agreement from you personally to the company. Some clients may have policies against contracting with limited companies. Check before you incorporate.

For ongoing work, you need to decide where the cut-off falls. Work completed before incorporation belongs to you personally. Work after incorporation belongs to the company. Invoice accordingly. If you invoice through the company for work done as a sole trader, HMRC may treat that as a transfer of value, which has tax consequences.

Assets are simpler. You can transfer business assets (equipment, tools, a van) from yourself to the company. This is a disposal for capital gains purposes. If the asset has increased in value, you may have a capital gain. You can claim incorporation relief under TCGA 1992 s.162 to defer the gain if you transfer the whole business as a going concern. Speak to your accountant about this.

Step 5: Handle VAT

If you are VAT-registered as a sole trader, your VAT registration is in your personal name. You cannot simply use it for the limited company. You must either:

  • Transfer the VAT registration using form VAT484 (change of details). This keeps your existing VAT number and avoids a break in registration.
  • Cancel the sole trader VAT registration and register the limited company separately. This triggers a VAT return and payment of any VAT due up to the cancellation date.

If your turnover is below the VAT threshold (£90,000 for 2025/26), you may not be registered. Once you incorporate, the company's turnover starts from zero for VAT purposes. You do not inherit the sole trader's turnover history. That means you may have time before you need to register for VAT. But if you expect to exceed £90,000 within 30 days, you must register from day one.

See our VAT and Making Tax Digital guide for more detail on registration and compliance.

Step 6: Notify HMRC and Close Your Sole Trader Records

You must tell HMRC that you have stopped self-employment. Do this through your personal tax account or by writing to HMRC. The date you stop is the day before your company starts trading.

You will need to file a final self assessment tax return (SA100 with SA103 self-employment pages) for the period up to the date you ceased trading. This return covers your sole trader income and expenses up to that point. After that, your income comes from the company (salary and dividends) and goes on your personal tax return each year.

Your company will file a corporation tax return (CT600) annually. You'll also need to file a confirmation statement every 12 months with Companies House.

Step 7: Set Up Business Bank Accounts

A limited company must have a separate business bank account. You cannot use your personal account for company transactions. Open a business current account with a bank that suits your needs. Most offer fee-free banking for the first 12 to 18 months.

You'll also need a separate savings or deposit account if you plan to hold retained profits. Some directors use a savings account to hold the corporation tax that will be due in 9 months and 1 day after the year-end.

What About IR35?

If you are a contractor working through your own limited company, IR35 applies. IR35 is legislation that determines whether you are genuinely self-employed or should be treated as an employee for tax purposes. If you fall inside IR35, you pay tax and NI at employee rates on your income, and the company pays employer NI.

Medium and large clients are responsible for determining your IR35 status. They issue a Status Determination Statement (SDS). If your client is small (fewer than 50 employees, turnover under £10.2M, balance sheet under £5.1M), you determine your own status.

If you are outside IR35, the limited company structure remains highly tax efficient. If you are inside IR35, the tax advantage largely disappears. Check your contracts and working practices before incorporating.

Common Mistakes When Switching

These are the mistakes we see most often:

  • Not transferring contracts properly. You invoice through the company for work done as a sole trader. HMRC can reclassify that income.
  • Forgetting to register for Corporation Tax. The three-month window is tight. Miss it and you face penalties.
  • Using the old VAT number. You must transfer or cancel it. Using the wrong number invalidates invoices.
  • Not updating professional indemnity insurance. Your policy as a sole trader does not cover the company.
  • Paying yourself too much salary. Above £12,570 triggers higher personal tax and employer NI without offsetting benefits.

Should You Incorporate Mid-Year or From a New Tax Year?

There is no perfect answer. It depends on your profit pattern and cash flow.

Incorporating mid-year means you file two tax returns for that year: a final sole trader return and a company return (if the company's year-end falls in that period). It also means your personal tax return includes both sole trader income and director income. That can be more work for your accountant, but it is perfectly normal.

Incorporating from 6 April (the start of the tax year) keeps the tax years clean. Your sole trader return covers the full previous year, and the company's first accounting period starts fresh. But you may have to wait months to see the tax savings.

Most people incorporate when the trigger happens: a new contract, a profit milestone, or simply reaching the point where the maths works. That is fine. Just plan the transition carefully.

What Happens to Your Existing Business Name?

If you trade as a sole trader under a business name (e.g. "Jones Plumbing Services"), you can continue using that name as a trading name of your limited company. The company's legal name must be registered with Companies House. The trading name can be different. Just make sure it is not already trademarked or registered by another company.

Update your invoices, contracts, and website to show the company's registered name and number alongside the trading name.

Final Practical Steps

Here is a checklist for the day you switch:

  • Register the company at Companies House
  • Register for Corporation Tax within 3 months
  • Register for PAYE and set up payroll
  • Open a business bank account
  • Transfer or cancel VAT registration
  • Notify HMRC of ceased self-employment
  • Transfer contracts and assets
  • Update insurance policies
  • Update your website, invoices, and marketing materials

If your turnover crossed the VAT threshold in the last 30 days, register inside the 30-day window. If you are unsure about incorporation relief on asset transfers, ask your accountant before completing the transfer. If your contracts include restrictive clauses, check those before telling clients.

Switching from sole trader to limited company is a significant step. Done properly, it saves you tax, protects your personal assets, and positions your business for growth. Done carelessly, it creates admin headaches and potential tax bills. Take it step by step, and get professional advice on your specific situation.

For a full breakdown of the costs and benefits for your numbers, speak to our team. We are ICAEW qualified accountants and work with businesses across the UK. Contact us to discuss your transition.