Tax & National Insurance · Income Tax & NI
Registering as a sole trader
Freelancing or side income over £1,000 a year means registering with HMRC as a sole trader — plus check your visa actually allows self-employment.
If you're earning over £1,000 per year from freelancing, side work, or your own business in the UK, you must register as a sole trader with HMRC (Her Majesty's Revenue and Customs). However, before you invoice your first client or accept any paid work, there's a crucial first step that many foreign residents overlook: you need to check that your visa actually permits self-employment. Registering with HMRC alone does not override immigration law, and working illegally can lead to serious consequences including visa cancellation and deportation.
Check Your Visa Allows Self-Employment
Self-employment is not automatically allowed under all UK visa categories. If your visa conditions restrict you to working for a specific employer or prohibit self-employment entirely, registering with HMRC will not make freelancing legal. For example, Student visa holders are not permitted to operate as freelancers, even if they declare all income to HMRC. The same applies to family visa routes and other sponsored pathways unless self-employment is explicitly named in your visa conditions.
Skilled Worker Visa Restrictions
If you hold a Skilled Worker visa (formerly Tier 2), self-employment is heavily restricted. You can only be self-employed if a licensed sponsor holds a genuine contract for services with you. This applies to specific professions such as dentists, barristers, and private tutors working through sponsoring practices. You can also take on supplementary freelance work, but only if it does not exceed 20 hours per week, takes place outside your main job's hours, and either relates to the same occupation code at the same level as your main role or is in a shortage occupation. Any freelance work that falls outside these parameters requires a new Certificate of Sponsorship and visa application before you begin work.
Other Visa Categories
Unsponsored and family routes such as spouse visas, partner visas, and ancestry routes generally offer more flexibility for self-employment. Settlement (Indefinite Leave to Remain) allows unrestricted self-employment. Student visas permit only very limited incidental work. If you are unsure whether your specific visa category allows self-employment, check your visa decision letter or visit gov.uk and search for the relevant immigration route before registering as a sole trader.
Registering for Self-Assessment with HMRC
Once you have confirmed your visa permits self-employment, you must tell HMRC you are now self-employed by registering for Self Assessment. This is the system HMRC uses to collect income tax and National Insurance contributions that are not deducted through PAYE (Pay As You Earn), which is how employee salaries are taxed automatically.
The 5 October Deadline
You must register for Self Assessment by 5 October after the end of the tax year in which you started trading. The UK tax year runs from 6 April to 5 April. For example, if you began self-employment in June 2025, you must register by 5 October 2026. You do not have to register immediately — you have until the following October — but registering early avoids stress and gives you time to set up proper record-keeping and payment arrangements.
If you earn less than £1,000 in a tax year, registration is optional. However, registering anyway can be worthwhile if you wish to claim business expenses to reduce your tax bill, if you need to prove self-employment for a mortgage application, or if you want an official record of your business.
How to Register
Register online using your National Insurance number and personal details via HMRC's Self Assessment service on gov.uk. You will need to provide your business start date and contact information. Once submitted, HMRC will send you a Unique Taxpayer Reference (UTR) within 10 working days. Keep this number safe — you will use it for all your tax correspondence with HMRC.
Income Tax and National Insurance Paid via Self-Assessment
As a sole trader, you pay income tax and National Insurance by filing an annual Self Assessment tax return. Unlike employees, you are responsible for calculating and paying these taxes — HMRC does not do it for you automatically.
Class 4 National Insurance
Most sole traders now pay only Class 4 National Insurance contributions. These are calculated as a percentage of your annual taxable profit and are paid alongside your income tax. Class 4 is payable on profits above the Lower Profits Limit of £12,570. For the current tax year, the rates are 6% on profits between £12,570 and £50,270, and 2% on profits above £50,270. Class 4 contributions do not count towards your future state pension entitlement, but you should be aware of this ongoing obligation when estimating your costs.
Class 2 National Insurance was historically a fixed weekly contribution, but since April 2024, most self-employed people with profits above the Small Profits Threshold (£6,725) receive National Insurance credits automatically without having to pay. If your profits fall below this threshold, Class 2 is optional but you may choose to pay voluntarily to protect your state pension entitlement and eligibility for certain benefits. You report this decision when you file your Self Assessment return.
Filing Your Tax Return and Paying Your Bill
You must file your Self Assessment tax return online by 31 January after the end of the tax year. For example, for income earned between 6 April 2025 and 5 April 2026, your return is due by 31 January 2027. This is also the deadline to pay any tax and National Insurance you owe. HMRC will calculate your tax bill for you once you submit your return and show you a breakdown of income tax, Class 4 National Insurance, and any other amounts due.
Many sole traders make 'payments on account' — two interim payments made in July and January — calculated as half of the previous year's total tax and National Insurance. When you file your return and pay your final bill in January, this is adjusted if necessary. Missing the 31 January deadline triggers an automatic £100 penalty, even if you owe no tax at all, and additional charges accumulate for extended delays.
Record-Keeping for Five Years
HMRC requires you to keep detailed records of all business income and expenses for at least five years after the 31 January Self Assessment deadline for each tax year. This means records for the 2025/26 tax year (due 31 January 2027) must be kept until 31 January 2032. Failing to keep proper records can result in a penalty of up to £3,000 per tax year — even if your tax calculation is entirely correct. In rare cases where HMRC suspects serious fraud, they can go back up to 20 years.
What Records You Need
- All invoices showing income from clients or customers
- Receipts and invoices for business expenses (rent, equipment, software, utilities, professional services)
- Bank statements showing business income and payments
- Records of personal money you have put into the business
- Records of loans and repayments
- Payroll records if you employ anyone
- VAT records if you are VAT-registered
You can keep records in paper form, digital form, or a combination of both. Digital copies must be clear, readable, and stored securely so you can access them if HMRC requests them. Many sole traders use accounting software such as Xero, QuickBooks, or FreeAgent to automate much of this process and store receipts digitally.
Best Practice for Record-Keeping
- Open a separate bank account for business income and expenses; do not mix personal and business money
- Update your records weekly or monthly rather than scrambling in January
- Capture and file receipts digitally as soon as you receive them
- Use accounting software to categorize expenses and reconcile your bank statements automatically
- Keep a simple spreadsheet of income and major expenses if you prefer a manual approach
- Regularly check your records against your bank statements to catch errors early
Key Deadlines and Penalties
Sole traders in the UK must meet several strict deadlines or face automatic penalties.
- 5 October: Register for Self Assessment in your second tax year of trading. Missing this deadline can trigger a 'failure to notify' penalty.
- 31 January: File your Self Assessment tax return online and pay any tax owed. Missing this incurs a £100 automatic penalty, with further charges for extended delays.
- 5 years after 31 January: Retain records of all income and expenses. Destroying records earlier can result in a penalty of up to £3,000 per tax year.
Summary: Your Action Checklist
- Confirm your visa allows self-employment before you start trading
- Register for Self Assessment by 5 October after your first tax year
- Open a separate business bank account to keep personal and business money apart
- Keep invoices, receipts, and records of all income and expenses
- File your tax return by 31 January each year and pay any tax due
- Store records securely for at least five years after the January 31 deadline
- Use accounting software to simplify record-keeping and ensure accuracy
Keep reading — Income Tax & NI
PAYE, tax codes and National InsuranceHow tax is taken from your salary automatically, what your tax code means, and how to spot (and fix) being on the wrong one.Getting your National Insurance numberWho needs to apply, who already has one via their visa, and how to apply — you can usually start work before it arrives.Self-assessment: who must file and howSide income, self-employment, or high earnings? The HMRC self-assessment deadlines, registration, and penalties to avoid.Always verify with official sources before acting on the information above.