How to Set Up a Business in the UK: A Step-by-Step Guide for New Small Business Owners

Starting a business in the UK involves more steps than most people expect, and fewer than most people fear. The process is straightforward if you know what needs to happen and in what order. This guide walks you through everything from choosing your business structure to getting your first invoice paid, with links to the relevant government resources and tools at each stage.

Step 1: Choose your business structure

The first decision every new UK business owner needs to make is how to structure their business. This affects how you pay tax, your personal liability, and how much admin is involved in running the business.

The three most common options for UK small businesses are:

Sole trader — the simplest structure. You register as self-employed with HMRC, file a Self Assessment tax return each year, and pay Income Tax and National Insurance on your profits. You are personally liable for any business debts. Most freelancers and one-person service businesses start here.

Limited company — you register a separate legal entity at Companies House. The company pays Corporation Tax on its profits, and you typically pay yourself a combination of salary and dividends. Your personal liability is limited to your shareholding. More admin than sole trader, but more tax-efficient above a certain income level and more credible to some clients.

Partnership — two or more people running a business together, sharing profits and liability. Each partner files a Self-Assessment tax return. A limited liability partnership (LLP) offers some personal liability protection.

For most people starting alone, sole trader is the right first step. If you are planning to take on employees, bring in investment, or are targeting corporate clients who prefer to deal with limited companies, registering at Companies House from the start makes more sense.

If you are unsure which structure suits your situation, HMRC's guidance at gov.uk is a good starting point, and a one-hour consultation with an accountant at the outset is money well spent.

Step 2: Choose and check your business name

Your business name is one of the first things clients will encounter and one of the few things that is genuinely hard to change later. It appears on your invoices, your website, your social profiles, and any marketing you do — so it is worth getting right from the start.

Before settling on a name, check:

• Companies House — if you are registering as a limited company, your name must be unique on the Companies House register. You can search at gov.uk
• Trade mark database — check the UK Intellectual Property Office database to make sure the name is not already trademarked in your sector
• Domain availability — check whether the .co.uk and .com domains are available before committing to a name
• Social media handles — consistent handles across LinkedIn, Instagram, X, and Facebook make your business easier to find

If you are still working out your business name, Built For Small Business's free Business Brand Kit toolgenerates business name ideas based on your industry and keywords, checks domain availability, and suggests matching social media handles, all in one place.

Step 3: Register your business with HMRC and Companies House

As a sole trader: You need to register as self-employed with HMRC by 5 October in your business's second tax year — but registering as soon as you start trading is better practice. You will receive a Unique Taxpayer Reference (UTR) number, which you use to file your Self Assessment tax return each year.

Register at: gov.uk/register-for-self-assessment

As a limited company, you register your company at Companies House, which costs £50 online and typically takes 24 hours. You will receive a Company Registration Number (CRN) and a certificate of incorporation. You then need to register the company for Corporation Tax with HMRC within three months of starting to trade.

Register at: gov.uk/register-a-company

VAT registration: If your turnover exceeds £90,000 in any 12-month you must register for VAT. You can also register voluntarily below this threshold, which can be beneficial if your clients are VAT-registered businesses and you have high VAT-able costs. Once registered, you will charge VAT on your sales and can reclaim VAT on your purchases.

Register at: gov.uk/vat-registration

Step 4: Open a dedicated business bank account

Keeping your personal and business finances completely separate is one of the most important habits to establish from day one. Mixing them creates accounting headaches, complicates your tax return, and looks unprofessional to clients and accountants alike.

For sole traders, there is no legal requirement to have a business bank account, but having one makes everything significantly easier. For limited companies, a separate business account is a legal requirement.

UK business bank account options range from traditional high street banks to digital-only providers. Many digital business accounts, such as Starling, Monzo Business, and Tide, offer free or low-cost accounts with good features for small businesses and are quicker to open than traditional bank accounts.

Step 5: Set up your invoicing and expense tracking from the start

The administrative habits you establish in your first month of trading tend to stick. Setting up proper invoicing and expense tracking from the outset saves significant time and stress later — particularly at Self Assessment time when you need to account for every pound of income and expenditure.

Invoicing: Every payment you receive from a client should be backed by a proper invoice. UK invoices must include your business name and address, the client's details, a unique invoice number, the date, a description of goods or services provided, and the amount owed. VAT-registered businesses must also include their VAT number and a breakdown of VAT charges.

Built For Small Business lets you create professional branded invoices, accept online payments via Stripe, and send automated payment reminders for overdue invoices, all from a free platform with no subscription required.

Expense tracking: Every business cost you incur, such as software subscriptions, travel, equipment, professional services, is potentially deductible against your tax bill. But only if you have a record of it. Log expenses as they happen rather than trying to reconstruct them at the end of the year.

Built For Small Business's expense tracking lets you log and categorise business expenses in the same place you manage your invoices and clients, so your financial records are always complete and ready when you need them.

Step 6: Understand your key tax obligations

Getting on top of your tax obligations early prevents the nasty surprises that catch many new business owners off guard.

Self Assessment (sole traders): You file a Self Assessment tax return each year covering the tax year ending 5 April. The online filing deadline is 31 January of the following year. You pay Income Tax on profits above your Personal Allowance (currently £12,570) and Class 4 National Insurance on profits above the Lower Profits Limit.

Corporation Tax (limited companies): Your company pays Corporation Tax on its profits. The current main rate is 25% for profits above £250,000, with a small profits rate of 19% for profits up to £50,000. You must file a Company Tax Return within 12 months of your accounting period end and pay Corporation Tax within 9 months and one day.

PAYE (if you employ staff): If you take on employees, you must register as an employer with HMRC and operate PAYE — deducting Income Tax and National Insurance from employee wages and paying employer National Insurance contributions. You must also auto-enrol eligible employees into a workplace pension scheme.

Making Tax Digital: HMRC is rolling out Making Tax Digital requirements across different taxpayer groups. VAT-registered businesses are already required to keep digital records and submit VAT returns through compatible software. Income Tax Making Tax Digital is being phased in for self-employed people and landlords from April 2026.

Step 7: Set up your client management from day one

The earlier you establish a system for managing client information, the less you will regret it later. A client whose details are stored properly, including contact information, what work was done, what was invoiced, and what was paid, is a client you can serve efficiently and professionally for years.

Many new business owners keep client records in their email inbox or a spreadsheet until the volume makes that approach unmanageable. By that point, migrating to a proper system is significantly more work than starting with one.

Built For Small Business's client managementgives you a dedicated place to store client records, view invoice history, and track payment status, connected directly to your invoicing, so everything is always up to date.

UK business setup checklist

• Business structure chosen — sole trader, limited company, or partnership
• Business name checked against Companies House, trade mark database, and domain availability
• Registered with HMRC as self-employed or a company registered at Companies House
• UTR number or Company Registration Number received
• Business bank account opened
• Invoicing system set up, first invoice template ready to send
• Expense tracking started, logging costs from day one
• VAT position assessed, register if required or beneficial
• Key tax deadlines noted, Self Assessment or Corporation Tax filing dates
• Client records system in place before the first client is onboarded

FAQ: Setting up a business in the UK

Do I need to register my business immediately when I start trading?
As a sole trader, you must register with HMRC by 5 October in your second tax year, but registering as soon as you start trading is a better practice and avoids any risk of penalties.

What is the difference between a sole trader and a limited company in the UK?
A sole trader is a self-employed individual trading in their own name, simpler to set up and run, but with personal liability for business debts. A limited company is a separate legal entity that limits your personal liability and can be more tax-efficient above a certain income level, but it involves more administrative requirements.

Do I need a business bank account as a sole trader?
There is no legal requirement, but it is strongly recommended. Keeping personal and business finances separate makes your accounting significantly easier and looks more professional to clients.

When do I need to register for VAT?
You must register for VAT when your taxable turnover exceeds £90,000 in any rolling 12-month period. You can register voluntarily below this threshold if it benefits your business.

What is a UTR number?
A Unique Taxpayer Reference is a 10-digit number HMRC issues when you register for Self Assessment. You use it to file your tax return and when communicating with HMRC about your tax affairs.

How do I choose a business name in the UK?
Check Companies House for name conflicts if registering a limited company, check the UK trade mark database, and confirm your preferred domain is available. The Built For Small Business Brand Kit tool can help you generate and check name ideas quickly.

Final thoughts

Setting up a business in the UK is a well-trodden path. The steps are clear, the government resources are genuinely helpful, and most of the admin, once done, stays done. The most important thing is to establish good habits from the start: register promptly, keep your finances separate, invoice professionally, and track every expense.

The administrative foundation you build in your first few months shapes how easy or difficult running your business feels for years to come.

Create your free Built For Small Business account, professional invoicing, expense tracking, and client management from day one. No credit card required.