If you are a UK agency founder, the sole trader vs limited company agency decision is one of the first major financial calls you will make. Get it right, and you save thousands in tax and sleep easier about liability. Get it wrong, and you are either paying too much HMRC or carrying personal risk you did not need to.
This is not a theoretical comparison. It is a practical breakdown using real agency numbers, real tax rates, and real scenarios. By the end, you will know which structure fits your agency's size, revenue, and ambitions.
What These Structures Actually Mean
Sole trader means you are self-employed. You and your business are legally the same entity. Your agency income is your personal income. Your business debts are your personal debts.
Limited company means your agency is a separate legal entity. It is owned by you (and possibly other shareholders) and run by directors. The company earns the income, pays corporation tax on its profits, and then you extract that profit as salary, dividends, or a combination of both.
There is no "right" answer for every agency. But there are clear wrong answers for specific situations. Let us work through them.
The Tax Difference: Real Numbers for an Agency Founder
Tax is usually the first reason agency founders consider incorporating. Here is how the numbers actually stack up.
Sole Trader Tax
As a sole trader, you pay income tax and Class 4 National Insurance on your profits. For the 2025/26 tax year:
- Personal allowance: £0 to £12,570 (0%)
- Basic rate: £12,571 to £50,270 (20% income tax, 9% Class 4 NI)
- Higher rate: £50,271 to £125,140 (40% income tax, 2% Class 4 NI above £50,270)
- Additional rate: above £125,140 (45% income tax, 2% Class 4 NI)
Take a solo web designer turning over £85,000 with £25,000 in expenses. Profit is £60,000. The tax bill looks like this:
- Personal allowance: £0 tax on first £12,570
- Basic rate: £7,540 income tax + £3,393 Class 4 NI on £37,700
- Higher rate: £3,892 income tax + £195 Class 4 NI on £9,730
- Total: £15,020
Effective tax rate: 25% of profit.
Limited Company Tax
Now take that same £60,000 profit inside a limited company. The company pays corporation tax first. At 19% (small profits rate), that is £11,400. Left in the company: £48,600.
You then extract that money. The standard tax-efficient approach for agency founders is a small salary and dividends.
- Salary: £12,570 (no income tax, no employee NI, no employer NI up to this level)
- Remaining profit after salary and employer costs: roughly £35,400 available for dividends
- Dividend tax at basic rate (8.75%): £3,098 (after £500 dividend allowance)
- Total tax: £11,400 corporation tax + £3,098 dividend tax = £14,498
Effective tax rate: 24.2% of profit.
At £60,000 profit, the difference is marginal. The sole trader pays £15,020. The limited company route costs £14,498. A saving of £522.
Now scale that profit up.
At £100,000 profit:
- Sole trader: roughly £28,700 in tax and NI
- Limited company: roughly £23,100 in corporation and dividend tax
- Difference: £5,600 in favour of the limited company
At £200,000 profit:
- Sole trader: roughly £73,700
- Limited company: roughly £49,800
- Difference: £23,900
The tax advantage of a limited company grows as your profit grows. That is because corporation tax (19% or 25%) is lower than the higher and additional rates of income tax. And dividends attract no National Insurance.
Liability: The Silent Risk
Tax is quantifiable. Liability is not. But it matters more.
As a sole trader, if a client sues your agency for a project that went wrong, they sue you. Your personal assets are on the line. Your house. Your savings. Your car.
As a limited company director, the company is the legal entity. If a client sues, they sue the company. Your personal assets are generally protected, unless you have given personal guarantees or acted fraudulently.
For agency founders, this is not theoretical. Agencies deal with intellectual property, campaign performance, data handling, and client deadlines. Scope creep happens. Projects burn. Clients get unhappy.
If you are a solo freelancer doing low-risk work for established clients, sole trader status may be fine. If you are running a 12-person digital agency billing £800k per year with 15 active clients, limited company protection is not optional. It is essential.
IR35 and Your Agency
IR35 is the off-payroll working rules. They apply when a contractor would be considered an employee if not for the intermediary (their limited company).
If you operate as a sole trader and work through an agency or direct client, you are already outside IR35 technically. But many clients will treat you as inside IR35 if you are a sole trader, because the risk assessment is simpler for them.
If you operate through your own limited company, you have more flexibility. You can structure engagements to sit outside IR35. But you must get it right. A Status Determination Statement (SDS) must be issued before you start work for medium or large clients. The CEST tool (Check Employment Status for Tax) can help, but it is directional guidance only and often unreliable for complex arrangements.
For agency founders who also take on contract work themselves, the limited company structure gives you more room to manage IR35. But it also adds compliance obligations. You need to issue SDS, keep records, and potentially pay employment taxes if HMRC challenges the status.
We cover this in more detail on our contractors and IR35 page.
Running Costs and Admin Burden
A limited company costs more to run. That is a fact.
- Annual accounts filed at Companies House: £50 to £150 for a basic filing, more if complex
- Corporation tax return (CT600): typically £300 to £600 from an accountant
- Payroll: even if you pay yourself only a salary, you need RTI (Real Time Information) submissions to HMRC. Accountants charge £20 to £50 per month for this.
- Confirmation Statement: £13 per year to Companies House
- Registered office address: £50 to £100 per year if you use an accountant's address
Total additional cost: roughly £800 to £1,500 per year compared to being a sole trader.
A sole trader files a self-assessment tax return once a year. That is it. No payroll. No Companies House filings. No corporation tax returns.
But here is the thing. The tax saving at £100,000 profit is £5,600. The additional admin cost is maybe £1,200. You are still £4,400 better off.
The question is whether you want the admin burden. Many agency founders start as sole traders, hit £50k to £80k profit, and then incorporate. That is a common and sensible path.
Exit and Sale: The BADR Advantage
If you ever plan to sell your agency, the limited company structure is almost certainly better.
Business Asset Disposal Relief (BADR) allows you to pay 14% capital gains tax on the sale of your business, rather than the standard 20% or 24%. The lifetime limit is £1 million of gains.
To qualify, you must:
- Hold at least 5% of the shares
- Be an officer or employee of the company
- Have held the shares for at least 2 years before disposal
A sole trader cannot use BADR. When you sell your sole trader business, you sell the assets (client contracts, goodwill, equipment). Those are subject to Capital Gains Tax at your marginal rate. If you are a higher rate taxpayer, that is 20% or 24% on the gain.
If you build an agency worth £500,000 and sell it:
- Sole trader: £500,000 gain at 24% CGT = £120,000 tax
- Limited company (qualifying for BADR): £500,000 gain at 14% = £70,000 tax
- Saving: £50,000
That alone can justify the limited company structure for anyone building a saleable agency.
When to Stay Sole Trader
Sole trader status is not wrong. It is right for specific situations.
- Profit under £40,000: The tax advantage of a limited company is minimal or negative once you factor in admin costs.
- Low risk work: If you design basic websites for small local businesses and never touch sensitive data, the liability protection matters less.
- You want simplicity: One tax return per year. No payroll. No Companies House. No dividend paperwork.
- You are testing the waters: Many agency founders start as sole traders to validate their business model before committing to the cost and complexity of a limited company.
If you are a solo freelancer billing £35k to £45k per year with low expenses, stay sole trader. You will not save enough in tax to justify the admin.
When to Incorporate
Incorporate when the numbers and the risk profile say it is time.
- Profit over £60,000: The tax saving is real and grows with profit.
- You have multiple clients: More clients means more liability exposure.
- You plan to hire staff or contractors: A limited company is the standard structure for employing people.
- You want to build a saleable asset: BADR requires a limited company structure.
- You work with large clients: Many big companies prefer or require working with limited companies for procurement and IR35 reasons.
- You want to retain profits in the business: A limited company lets you leave money inside the company, deferring personal tax until you extract it.
A typical trigger point: your profit hits £50,000 to £60,000 and you see it growing. That is when the conversation shifts from "should I?" to "when should I?"
How to Switch from Sole Trader to Limited Company
If you decide to incorporate, the process is straightforward but has steps you must get right.
- Register the company at Companies House. You can do this yourself for £12 or use an accountant's formation service (typically £30 to £50).
- Open a business bank account in the company's name. Do not mix personal and company funds.
- Register for corporation tax with HMRC within 3 months of starting to trade through the company.
- Set up payroll if you plan to take a salary. You need to register as an employer.
- Transfer assets from your sole trader business to the company. This includes client contracts, equipment, and goodwill. Get a valuation for goodwill if it is significant.
- Close your sole trader registration with HMRC. File your final self-assessment as a sole trader.
- Notify your clients of your new company name, registered address, and VAT number (if applicable).
One common mistake: not transferring client contracts properly. If your sole trader entity held the contract and you stop trading, the client may have no legal relationship with your new company. Get a novation agreement or new contract signed.
Another: forgetting about the VAT registration. If you are VAT registered as a sole trader, you need to cancel that registration and register the new company. HMRC can take 4 to 6 weeks to process this, so plan ahead.
VAT: The Same Either Way
VAT registration is based on turnover, not structure. If your turnover exceeds £90,000, you must register for VAT regardless of whether you are a sole trader or a limited company.
The VAT scheme you choose matters more than the structure. Flat rate VAT can simplify things for small agencies. But if you are a limited cost trader (spending less than 2% of turnover on relevant goods), you must use standard accounting. Most digital agencies fall into this category because their main costs are salaries and software, not physical goods.
We cover VAT in more detail on our tax and compliance page.
Directors' Loan Account: A Trap to Avoid
If you incorporate, you will have a directors' loan account (DLA). This tracks money you lend to or borrow from the company.
If you take more money out of the company than you have put in (through salary, dividends, or expenses), the DLA goes overdrawn. That is a loan from the company to you.
If the loan exceeds £10,000 at any point in the year, it is a taxable benefit. You must report it on a P11D form and pay Class 1A NI at 13.8% on the cash equivalent.
If the loan is not repaid within 9 months of the company's year end, the company pays S455 tax at 33.75% on the outstanding amount. You can reclaim this once the loan is repaid, but it ties up cash.
Do not treat your company bank account as your personal account. It is not. Keep a clear record of every withdrawal and repayment.
Which Structure Wins for Most Agency Founders?
For agency founders with profits consistently above £60,000, the limited company is the better choice. The tax saving, liability protection, and exit options outweigh the additional admin cost and complexity.
For solo founders earning under £40,000 profit, sole trader is usually the right call. Keep it simple. Focus on growing the business. Revisit the decision when your profit crosses £50,000.
Between £40,000 and £60,000 profit, the answer depends on your specific circumstances. If you have liability exposure, plan to hire, or want to build a saleable business, incorporate earlier. If you are low-risk and want simplicity, stay sole trader a bit longer.
The worst move is not making a decision at all. Many agency founders drift as sole traders for years, paying more tax than necessary and carrying personal risk they do not fully understand.
If your profit has crossed £50,000 and you are still a sole trader, it is time to have the conversation. Speak to our ICAEW qualified team and we will run the numbers for your specific situation.
Frequently Asked Questions
Can I switch from sole trader to limited company mid-year?
Yes. You close your sole trader accounts at a specific date (usually the day before the company starts trading) and file a final self-assessment for the sole trader period. The company then starts from the incorporation date. HMRC is used to this. Just make sure you file the correct returns for both periods.
Does being a limited company affect my ability to get a mortgage?
It can. Some lenders prefer employed income over dividend income. But many specialist lenders now accept limited company director income. You typically need 2 to 3 years of accounts and dividend vouchers. If you are planning to apply for a mortgage, speak to a broker