You have a growing agency. You are billing £60,000 or £160,000 or £600,000 a year. Someone, your accountant, a fellow founder, a well-meaning friend, has told you to incorporate. "Set up a limited company," they say. "It's more tax efficient."
They are right, often. But they rarely tell you what the cost of incorporation actually looks like in pounds and pence.
Incorporation is not a free upgrade. It is a structural change that shifts how you pay tax, how you report to HMRC, and how you take money out of your business. It also introduces costs you did not have as a sole trader or partnership. Some of those costs are one-off. Some are annual. Some are hidden until your first year-end.
This is the reality check. Here is what incorporation actually costs an agency founder in 2025/26.
The Setup Costs: What You Pay Before You Trade
Registering a limited company at Companies House costs £12 online. That is the cheapest part of the process.
But you need more than a company number to trade properly. Here is what most agency founders actually spend in the first month:
- Company formation agent (if you use one): £20-£60. Worth it if you want your SIC code right and your articles of association drafted for a standard agency structure. Most accountants recommend a standard formation package rather than the £12 DIY route, because a wrong SIC code or missing shareholder agreement creates problems later.
- Registered office address: £50-£150 per year if you do not use your home address. Many agency founders use their accountant's address or a serviced office. Using your home address puts it on public record. If you work from a flat in Shoreditch, your clients and suppliers will see that address on Companies House.
- Business bank account: Free to £15 per month. Most high street banks offer free business accounts for the first 12-24 months. After that, expect £5-£15 per month. Some challenger banks like Starling or Tide are free permanently but lack features like multi-currency accounts that agencies with UAE clients need.
- Domain and website refresh: £20-£200. You may want a new domain or to update your existing site to show your limited company name. Not mandatory, but most founders do it.
- Professional indemnity insurance: £200-£800 per year depending on turnover and agency type. As a limited company, you are a separate legal entity. Your personal assets are protected, but the company still needs cover. Most agency clients require PI insurance before signing a contract.
Total first-month setup cost: roughly £350-£1,200 depending on your choices.
That is not a huge number for a growing agency. But it is not zero either. And it is the smallest part of the cost of incorporation.
The Ongoing Costs: What You Pay Every Year
This is where the real numbers land. The annual cost of running a limited company is higher than most sole traders expect.
Accountancy fees: £1,200-£4,000+ per year
As a sole trader, you can file your own self-assessment tax return for free. Your tax affairs are straightforward: one set of accounts, one tax return, one payment on account.
As a limited company, you need:
- Annual accounts filed at Companies House (abridged or full)
- A corporation tax return (CT600) filed with HMRC
- Confirmation statement (formerly annual return) filed at Companies House
- PAYE registration and RTI (Real Time Information) submissions if you pay yourself a salary
- Dividend vouchers and minutes if you take dividends
- Personal tax returns for directors (self-assessment)
A decent accountant handling all of this for a small agency typically charges £1,200-£2,500 per year. For agencies turning over £250k+ with multiple directors, contractors, and complex revenue streams, expect £3,000-£4,500.
At Agency Founder Finance, we are ICAEW qualified accountants who work exclusively with agency founders. Our fees reflect the complexity of agency finances, retainer billing, project accounting, contractor payments, and international clients. We do not offer a £49-per-month service because agency accounts are not that simple.
Payroll and pension: £200-£600 per year
If you pay yourself a salary (and you should, for tax efficiency), you need payroll software or an outsourced payroll provider. Most accountants include basic payroll for one director in their fee. If you have employees, payroll costs more.
You also need to set up a workplace pension scheme. Even if you are the only employee, you must auto-enrol yourself. The pension provider charges setup and ongoing fees. NEST is free for employers but charges 1.8% on contributions. Other providers charge £10-£30 per month.
Software costs: £300-£1,200 per year
As a sole trader, you might use FreeAgent or QuickBooks for £10-£20 per month. As a limited company, you need accounting software that handles:
- VAT returns (if you are registered)
- Dividend tracking and director loan accounts
- Multi-currency if you have UAE or US clients
- Project profitability tracking (key for agencies)
Xero costs £14-£54 per month depending on the plan. QuickBooks Online is similar. FreeAgent is included with some bank accounts. Add Dext for receipt capture at £10-£20 per month, and Float or Spotlight Reporting for cash flow forecasting at £20-£50 per month.
Total annual software cost for a properly set-up agency: £500-£1,200.
Companies House filing fees: £13 per year
Your confirmation statement costs £13 annually. That is the cheapest recurring cost on this list.
The Tax Costs: What Incorporation Changes
This is where most agency founders focus, and rightly so. The tax savings of incorporation are real. But the tax costs are also real.
Corporation tax
Your limited company pays corporation tax on its profits. For the 2025/26 tax year:
- 19% on profits up to £50,000
- Marginal relief between £50,000 and £250,000
- 25% on profits above £250,000
Compare that to a sole trader paying 20%, 40%, or 45% income tax on profits. The saving is significant, but only if you leave profits in the company. The moment you take money out as dividends, you pay additional tax.
Dividend tax
Dividends are paid from post-tax profits. The company pays corporation tax first, then you pay dividend tax on what you receive:
- 8.75% for basic rate taxpayers
- 33.75% for higher rate taxpayers
- 39.35% for additional rate taxpayers
The dividend allowance is now £500 per year. That is down from £2,000 in 2022. For most agency founders taking £50,000-£100,000 in dividends, the effective tax rate on extracted profits is roughly 25-35% after corporation tax and dividend tax combined.
That is still lower than 40% or 45% income tax as a sole trader. But it is not the 10% or 15% some online calculators suggest.
Employer's National Insurance
If you pay yourself a salary above the secondary threshold (£9,100 in 2025/26), your company pays 13.8% employer NI on the excess. Most agency founders take a salary of £12,570 (the personal allowance threshold). The employer NI on that is roughly £480 per year.
That is a cost you did not have as a sole trader.
The Hidden Costs: What Catches Founders Out
These are the costs that do not appear on a comparison table but hit your bank account anyway.
Director's loan account complications
If you take money from the company that is not salary, dividends, or expenses, it goes into your director's loan account. If that balance is overdrawn by more than £10,000 at any point, the company pays S455 tax at 33.75%. That tax is refundable when you repay the loan, but the cash flow impact can be brutal.
I have seen agency founders take a "temporary" £15,000 draw to cover a personal tax bill, only to trigger a £5,062 S455 charge that they did not budget for.
IR35 costs for contractors
If your agency uses contractors, and you are a medium or large agency, you must issue Status Determination Statements (SDS) before engaging them. If HMRC determines the contractor is inside IR35, you owe employer NI and apprenticeship levy on their payments. That adds roughly 14.3% to the cost of every contractor deemed inside IR35.
For a digital agency with five contractors at £400 per day each, an IR35 determination error could cost £14,300 per year in unexpected employer costs.
VAT registration and administration
The VAT registration threshold is £90,000. If your agency turnover exceeds that, you must register. VAT adds administrative cost: quarterly returns, reconciliations, and potential penalties for late filing. If you use the Flat Rate Scheme, you keep some of the VAT, but the Limited Cost Trader rules mean most agencies cannot use it profitably.
VAT is not a cost of incorporation per se, sole traders also register, but the complexity is higher for a limited company because you have more transactions to track.
The Cost-Benefit Calculation: When Incorporation Makes Sense
Here is the practical question: at what point does the cost of incorporation justify itself?
For a sole trader agency founder earning £40,000 profit per year, the tax saving from incorporation is modest. You save the difference between 20% income tax and 19% corporation tax plus 8.75% dividend tax on extracted profits. The saving is maybe £1,000-£2,000 per year. But your accountancy fees go up by £1,000-£2,000. You break even or lose money.
For an agency founder earning £100,000 profit per year, the numbers shift. As a sole trader, you pay 40% on profits above £50,270. As a limited company, you pay 19% corporation tax and 33.75% dividend tax on extracted profits. The combined rate is roughly 46% on extracted profits above the basic rate band. But you can leave profits in the company and defer extraction. That deferral alone can save thousands per year.
For an agency founder earning £250,000 profit per year, incorporation is almost certainly the right move. The corporation tax rate on retained profits is 25% (above £250k) or marginal relief (between £50k and £250k). The alternative is 45% income tax as a sole trader. The saving on retained profits alone is 20%, £50,000 per year on £250,000 profit.
That saving dwarfs the £3,000-£5,000 annual cost of running a limited company.
The Real-World Example
Let me give you a specific scenario. A 12-person digital agency in Manchester's Northern Quarter. Turnover of £800,000 per year. Gross margin of 58%. Operating profit of £180,000.
The founder, a single director, takes a salary of £12,570 and dividends of £80,000. The remaining £87,430 stays in the company.
Annual costs of incorporation:
- Accountancy: £3,200
- Software (Xero, Dext, Float): £1,100
- Payroll and pension: £480
- Employer NI on salary: £480
- Companies House: £13
- PI insurance: £600
- Total: £5,873
Tax paid: £34,200 corporation tax on £180,000 profit (marginal relief applies). £26,800 dividend tax on £80,000 withdrawn.
Total tax and costs: £66,873.
As a sole trader on £180,000 profit: £63,400 income tax and NI (2025/26 rates). Plus accountancy fees of £600. Total: £64,000.
In this scenario, the founder pays roughly £2,900 more in the limited company structure. But £87,430 stays in the company, available for reinvestment, equipment, hiring, or future extraction at potentially lower rates.
The trade-off is clear: you pay slightly more now for significantly more control over timing and reinvestment.
What to Do Before You Incorporate
If you are still a sole trader or partnership and considering incorporation, do these three things first:
- Run the numbers with your accountant. Do not use an online calculator. Your specific profit level, dividend strategy, and reinvestment plans change the calculation completely. Ask your accountant to model both scenarios for the next three years.
- Check your contractor mix. If you use contractors, incorporation triggers IR35 obligations. If your contractor mix has changed in the last 12 months, ask your accountant before year-end. You may need to restructure engagements.
- Plan your extraction strategy. The tax saving from incorporation comes from leaving money in the company. If you need to extract all profit every year to fund your lifestyle, the benefit shrinks. Know your personal spending needs before you commit.
Incorporation is not a magic bullet. It is a structural choice with real costs and real benefits. For most agency founders turning over £150,000 or more, the benefits outweigh the costs. But you should go in with your eyes open, not because a LinkedIn post told you to "get a Ltd co."
If you want to talk through your specific numbers, our ICAEW qualified team at Agency Founder Finance works exclusively with agency founders. We know how agency finances work, retainer vs project, contractor costs, international clients, and exit planning. Get in touch and we will run the comparison for your agency.