🇬🇧 English·May 2026·10 min read

Self-Employed in the UK: Complete Tax Guide 2025–26

Working for yourself in the UK as an expat or international worker? This guide covers everything, registration, allowable expenses, tax rates, National Insurance, and the key deadlines for the 2025–26 tax year.

Need to file your Self Assessment return?

TaxEase UK guides you through all 15 steps, in your language, no jargon.

Try free →

Am I self-employed for UK tax purposes?

You are self-employed if you run your own business and are responsible for its success or failure. This includes:

  • Sole traders (tradespeople, consultants, freelancers)
  • Gig economy workers (Uber, Deliveroo, TaskRabbit)
  • Directors of limited companies who pay themselves dividends
  • People with a side business alongside employment
  • Those earning rent from UK property

💡 If your self-employment income is under £1,000 in a tax year, you may qualify for the Trading Allowance and won't need to file a Self Assessment return for that income.

Step 1: Register with HMRC

You must register as self-employed by 5 October 2026 (for income earned in the 2025–26 tax year). Late registration can result in penalties.

  1. Go to gov.uk/register-for-self-assessment
  2. Select “I am self-employed”
  3. Create or sign in to your Government Gateway account
  4. HMRC will post your UTR (Unique Taxpayer Reference), a 10-digit number, within 10 working days
  5. You'll also be automatically enrolled in Class 2 National Insurance (no longer compulsory, see NI section below)

⚠️ Even if you haven't received your UTR yet, you must register by the deadline. HMRC's postal system can be slow, register early.

Key dates for 2025–26

5 April 2026
End of 2025–26 tax year
The tax year runs 6 April 2025 – 5 April 2026.
5 October 2026
Registration deadline
Register as self-employed if you haven't already.
31 October 2026
Paper return deadline
For those filing a paper SA100 form (not recommended).
31 January 2027
Online return + payment
File your online return and pay any tax owed by midnight.

How is self-employment income taxed?

Tax is calculated on your profit (income minus allowable expenses), not your turnover. The 2025–26 rates are:

BandTaxable incomeRate
Personal Allowance£0 – £12,5700%
Basic Rate£12,571 – £50,27020%
Higher Rate£50,271 – £125,14040%
Additional RateOver £125,14045%

Note: If your income exceeds £100,000, your Personal Allowance is reduced by £1 for every £2 over that threshold, it disappears completely at £125,140.

National Insurance for self-employed (2025–26)

As a self-employed person you pay Class 4 NI on your profits:

  • 6% on profits between £12,570 and £50,270
  • 2% on profits above £50,270

Class 2 NI stopped being compulsory from 6 April 2024. If your profits are above the small profits threshold, contributions are treated as paid and you owe nothing. Below that threshold you can still choose to pay voluntary Class 2 to keep building your State Pension record, which is worth doing in a low-profit year. Check the current threshold and weekly rate on gov.uk.

✅ If your profits are below £6,725 (Small Profits Threshold), you pay no Class 4 NI. You can choose to make voluntary Class 3 NI contributions to protect your State Pension entitlement.

Allowable expenses: what can you deduct?

The lower your profit, the less tax you pay. These expenses are deductible if they are “wholly and exclusively” for business:

🚗
Mileage & vehicle costs
45p per mile for first 10,000 miles, 25p after. Or claim actual costs proportional to business use.
🏠
Home office
£6/week flat rate with no receipts needed, or calculate actual costs (heating, electricity, broadband proportional to room/usage).
📱
Phone & internet
Business proportion only. If 70% of your phone use is business, claim 70% of the bill.
🖥️
Equipment & tools
Laptops, machinery, tools. The Annual Investment Allowance lets you deduct the full cost in the year of purchase.
💼
Professional fees
Accountant fees, legal advice related to your business, professional memberships.
📚
Training & subscriptions
Courses that improve skills you already use in your business (not career changes). Trade publications and professional subscriptions.
🏥
Insurance
Public liability, professional indemnity, and other business insurance premiums.
📦
Stock & materials
Raw materials, stock for resale, packaging, anything directly used in producing your goods or services.

Payment on Account, the trap most expats miss

If your tax bill exceeds £1,000, HMRC requires you to make advance payments towards the next year's tax. These are called Payments on Account.

Each payment is 50% of your current year's bill, due on:

  • 31 January 2027, first payment (alongside your actual 2025–26 bill)
  • 31 July 2027, second payment

⚠️ Example: If your 2025–26 tax bill is £3,000, you must pay £3,000 + £1,500 (first Payment on Account) = £4,500 on 31 January 2027. Many people are caught off-guard by this.

Tips to legally reduce your tax bill

  • Claim all allowable expenses, many self-employed workers under-claim. Keep records of everything.
  • Use the Marriage Allowance, if your spouse or civil partner earns under £12,570, they can transfer £1,260 of their Personal Allowance to you, saving up to £252/year.
  • Make pension contributions, contributions to a personal pension reduce your taxable income pound for pound.
  • Claim the Trading Allowance, if you have small additional income (e.g., selling items online), the first £1,000 is tax-free.
  • Consider incorporating, if your profits exceed around £50,000, operating through a limited company may reduce your overall tax burden. Consult an accountant.

Which SA100 supplementary pages do I need?

SA103S
Self-employment (short)
Your annual turnover is under £85,000. This covers most sole traders.
SA103F
Self-employment (full)
Your annual turnover is £85,000 or more, or your accounts are more complex.
SA102
Employment
You also have income from employment (PAYE) alongside self-employment.
SA105
UK property
You earn rental income from UK property.
SA106
Foreign income
You have income from outside the UK, including rent or salary from your home country.

Ready to file your 2025–26 return?

TaxEase UK walks you through all 15 steps in your own language, free for straightforward returns.

Try free, no account needed →

Filing deadline: 31 January 2027