How to Register With HMRC When You Start a Business.

When you start working for yourself, you have to tell the government, so it knows to collect your tax. Who you tell depends on how you set up:

• Working for yourself as a sole trader (just you, under your own name or a trading name): you register with HMRC for Self Assessment once you earn more than £1,000 in a tax year. It's free.
• Setting up a limited company: you register the company with Companies House. It costs £100 online, and HMRC usually sets the company up for Corporation Tax at the same time.

Some other things are separate and need their own sign up, like VAT, CIS and taking on staff. Registering for one never does the others. They're all covered below.

• HMRC: HM Revenue and Customs, the government department that collects tax.
• Sole trader: someone who works for themselves and is the business. Most trades start this way.
• Limited company: a business set up as its own legal thing, separate from you. You run it as a director.
• Companies House: the government office that keeps the list of every UK company.
• Self Assessment: how a sole trader tells HMRC what they earned each year, on a tax return, so the right tax is paid.
• Tax year: the year tax is counted over. It runs from 6 April to 5 April the next year, not January to December.
• UTR: your Unique Taxpayer Reference, a 10 digit number HMRC gives you when you register. You'll need it for your tax returns.
• Corporation Tax: the tax a limited company pays on its profits.
• VAT: Value Added Tax, added on top of your prices once your business is big enough.
• CIS: the Construction Industry Scheme, HMRC's rules for tax on building work done for a contractor.
• PAYE: Pay As You Earn, how tax comes out of your staff's wages.
• Making Tax Digital: HMRC's new way of sending your figures, through an app or software, every 3 months.

You need to register for Self Assessment if you earn more than £1,000 from working for yourself in a tax year. That's the money coming in, before you take off what you've spent.

Under £1,000, the trading allowance means you usually don't need to tell HMRC at all. You might still choose to register, for example if you've made a loss you want to claim.

The deadline: register by 5 October after the end of the tax year you started in. So if you started in June 2026, that tax year ends on 5 April 2027, and you'd register by 5 October 2027. You can register sooner, and it's easier to do it straight away.

How to register, step by step

1. Go to Register for Self Assessment on GOV.UK ↗.
2. Choose that you're self employed.
3. Sign in to your HMRC online account, or make one if you don't have one yet.
4. Fill in your details and the date you started working for yourself. Use your real start date, not a guess.
5. Wait for your UTR. HMRC usually posts it about 15 days after you register (longer if you live abroad). It also shows in the HMRC app and your online tax account.
6. Keep the UTR somewhere safe. You'll need it every year.

Keep a note of what you earn and spend from your very first job, even before you've registered.

Making Tax Digital means keeping your figures in an app or software that works with HMRC, and sending HMRC an update every 3 months, as well as your yearly return. It's being brought in for sole traders bit by bit, based on how much comes in each year:

• Over £50,000 (in the 2024 to 2025 tax year): from 6 April 2026.
• Over £30,000 (in the 2025 to 2026 tax year): from 6 April 2027.
• Over £20,000 (in the 2026 to 2027 tax year): from 6 April 2028.

The figure is everything coming in before you take off what you've spent. HMRC won't sign you up for you: you check and sign up yourself. If you're just starting out, you'll do at least one normal Self Assessment return first.

You set a company up with Companies House. Online it costs £100 and is usually done within 24 hours. By post it's £124 and takes 8 to 10 days.

HMRC usually sets the company up for Corporation Tax at the same time. As a director, you then have yearly jobs to keep up with: company accounts, a confirmation statement (a yearly check that the company's details are right), Corporation Tax, and any payroll, VAT or CIS.

Proving who you are: since 18 November 2025, every company director has to verify their identity with Companies House. It's free through GOV.UK One Login (the government's sign in), or an accountant registered with Companies House can do it for you, though they may charge.

Don't set up a company and then forget about it because it isn't earning yet. A company that isn't trading can still have to send things in.

• CIS: You do building work for a contractor, or pay subcontractors yourself. If you work for a contractor and aren't registered, they have to take 30% off your pay instead of 20%.
• VAT: What comes in over the last 12 months goes over £90,000, or you expect it to in the next 30 days. You can also choose to register sooner.
• PAYE: You take someone on. Register before their first payday, but no more than 2 months before.
• Trade schemes: Your work needs one by law, like Gas Safe for gas work.
• Data protection fee: You keep customers' details, like names and phone numbers. Most businesses that keep them pay a yearly fee to the ICO (the Information Commissioner's Office, which looks after data protection), unless they're exempt.

Use the official checkers for your own business:

• GOV.UK: CIS for subcontractors ↗
• GOV.UK: when to register for VAT ↗
• GOV.UK: register as an employer ↗
• ICO: do you need to pay the data protection fee? ↗

Not on its own. Having a UTR, sending invoices, having a company or being registered for CIS doesn't automatically make you self employed for tax. It depends on how each job works: who decides how and when you work, whether you can send someone else, and who provides the tools.

• Never pay a website just to reach a free government service
• Never ignore HMRC letters because work is quiet
• Never log in to HMRC with someone else's details
• Don't guess your start date
• Don't assume your accountant has done something: check