⚡ Quick Answer
Register as self-employed by notifying HMRC online at gov.uk/register-for-self-assessment. You’ll need your National Insurance number. HMRC sends a Unique Taxpayer Reference (UTR) by post within approximately 10 working days. Deadline: 5 October following the end of the tax year you started self-employment. You then file a Self Assessment return annually (deadline 31 January online) and pay Class 2 and Class 4 National Insurance. Registration is free. Keep records of all income and expenses from day one.
The registration process for self-employment is genuinely straightforward — about 20 minutes online and it costs nothing. What matters more than the registration itself is understanding what you’re signing up for: annual tax returns, National Insurance contributions, “payments on account” that can surprise first-year self-employed people, and record-keeping that must start from day one.
Who Needs to Register
You need to register as self-employed if:
- You’re working for yourself and earning money from that work (freelancing, contracting, sole trading)
- You have a side business alongside employed work
- Your self-employment income exceeds £1,000 in a tax year (below £1,000, the Trading Allowance means no registration is needed)
If you’re setting up as a limited company rather than a sole trader, the process is different — you incorporate through Companies House separately.
The Registration Process
Step 1: Get your National Insurance number
You’ll need your NI number to register. Find it on any previous payslip, P60, or HMRC correspondence. If you can’t locate it, call HMRC on 0300 200 3500.
Step 2: Register online
Go to gov.uk and search “register for Self Assessment.” Create or log into a Government Gateway account (or use GOV.UK One Login). Complete the registration form confirming when you started self-employment and the nature of your business. Takes approximately 20 minutes.
Step 3: Receive your UTR
HMRC sends your Unique Taxpayer Reference (UTR) — a 10-digit number — by post within approximately 10 working days. Keep this safe; you need it for all future Self Assessment correspondence and returns.
Step 4: Activate your online account
HMRC may also send an activation code for your online Self Assessment account. Once activated, you can view correspondence, manage your tax affairs, and eventually submit returns online.
Key Deadlines
- Registration: by 5 October following the tax year you started self-employment
- Online tax return: by 31 January (for the previous April-to-April tax year)
- Paper return: by 31 October
- Tax and NI payment: by 31 January
- Second payment on account (advance toward next year): by 31 July
Payments on Account — The First-Year Surprise
In your first year filing a Self Assessment return with a meaningful tax bill, you may face “payments on account” — advance payments toward next year’s expected tax bill. These are due alongside your current year’s tax in January, effectively making the first year’s January payment considerably larger than expected. Understanding this in advance prevents the common shock of discovering you owe roughly 150% of what you expected.
Our Self Assessment guide for the self-employed covers payments on account and the other common mistakes in detail.
Frequently Asked Questions
Can I be both employed and self-employed?
Yes — this is very common. Employment income is taxed through PAYE by your employer. Self-employment income is reported separately through Self Assessment. The two income streams are combined to calculate your overall tax position.
Do I need a business bank account to be self-employed?
No legal requirement for sole traders, but it’s strongly recommended. Keeping business income and expenses in a dedicated account makes tax return preparation significantly easier and reduces the risk of claiming personal expenses accidentally.
Register at gov.uk/register-for-self-assessment.
