Self-Employed Tax Calculator UK 2025/26 — Sole Trader Income Tax & National Insurance
If you are self-employed as a sole trader, you pay income tax and National Insurance on your profits — not your turnover. This calculator works out your exact tax and NI bill for 2025/26, including Class 2 and Class 4 NI, your payment on account schedule, and your effective tax rate. Understand what you owe before 31 January.
2025/26: Personal allowance £12,570. Basic rate 20% up to £50,270. Higher rate 40% up to £125,140. Class 4 NI: 6% (£12,570–£50,270), 2% above. Class 2 NI is now voluntary. Payment on account = 50% of prior year's tax × 2, due Jan and Jul. This is an estimate — always confirm with an accountant.
How Are Self-Employed People Taxed in the UK?
As a sole trader, you are taxed on your business profits — the income you earn from self-employment minus the allowable business expenses you incur. Unlike employees who have tax deducted automatically through PAYE, self-employed people report their income and expenses through a Self Assessment tax return, due every 31 January for the previous tax year.
Self-employment tax has two components: income tax (the same rates as employees) and National Insurance contributions (Class 2 and Class 4, which are different from the employee Class 1 contributions). Understanding both is essential to budgeting correctly throughout the year.
Income Tax Rates for Self-Employed People 2025/26
| Taxable profit band | Tax rate | What it means |
|---|---|---|
| Up to £12,570 | 0% | Personal allowance — tax-free |
| £12,571 – £50,270 | 20% | Basic rate |
| £50,271 – £125,140 | 40% | Higher rate |
| Above £125,140 | 45% | Additional rate (personal allowance withdrawn above £100,000) |
National Insurance for Self-Employed 2025/26
| NI Class | Rate | When payable |
|---|---|---|
| Class 2 | £3.45/week (voluntary) | Profits above £12,570 — now voluntary but still worth paying for State Pension credits |
| Class 4 | 6% | On profits between £12,570 and £50,270 |
| Class 4 upper | 2% | On profits above £50,270 |
From April 2024, Class 2 NI became voluntary. However, paying it (£179.40/year) still earns you qualifying NI years for the State Pension and contributory benefits — making it very good value for most self-employed people whose profits are above £12,570.
Payment on Account — What Is It and How Does It Work?
Payment on account is HMRC's system for collecting tax in advance. If your Self Assessment tax bill exceeds £1,000 and less than 80% of your tax is collected at source, HMRC requires you to make two advance payments towards your next year's tax bill. Each payment on account is 50% of your current year's tax bill, due on 31 January and 31 July. The following 31 January, you pay any balancing payment (the difference between your actual liability and the payments on account already made).
This system means that in your first year of self-employment, your January bill can be eye-wateringly large — you pay the first year's actual tax plus the first payment on account for the next year. Plan ahead and set aside money throughout the year.
Allowable Business Expenses for Sole Traders
You can deduct allowable expenses from your income before calculating your tax. Allowable expenses must be incurred wholly and exclusively for the purposes of your business. Common allowable expenses include:
- Office costs — stationery, printing, phone and broadband bills (business proportion)
- Travel — fuel, parking, train and bus fares for business journeys (not commuting to a regular workplace)
- Stock and materials — goods you buy to sell on or use in your work
- Marketing — website costs, advertising, business cards
- Professional fees — accountant fees, solicitor fees for business matters
- Training — courses and books directly related to your current trade
- Working from home — flat rate of £26/month (or actual apportioned costs)
- Capital allowances — equipment, machinery, vehicles using annual investment allowance
You cannot claim personal expenses, client entertainment, everyday clothing (even if worn for work), or fines and penalties.
The £1,000 Trading Allowance
If your self-employment income is £1,000 or less in a tax year, you do not need to declare it or pay tax on it — this is the trading allowance. You also do not need to register for Self Assessment for this income. If your income is higher than £1,000, you must register and can choose to deduct either actual expenses or the £1,000 trading allowance (whichever is more beneficial).
Self Assessment Deadlines
| Deadline | What is due |
|---|---|
| 5 October (after end of tax year) | Register for Self Assessment if you are new to self-employment |
| 31 October | Paper tax return deadline |
| 31 January | Online tax return deadline + balancing payment + first payment on account |
| 31 July | Second payment on account |
Tips for Managing Your Self-Employment Tax
The most common mistake self-employed people make is spending all their income without setting aside money for the tax bill. A good rule of thumb is to save 25–30% of your profit each month in a separate account earmarked for tax. If you earn above the higher rate threshold, save closer to 45%.
Consider making pension contributions — contributions to a registered pension scheme reduce your net relevant earnings for income tax purposes, which can bring you back below the higher rate threshold and save significant amounts. A £10,000 pension contribution by a higher-rate taxpayer effectively costs only £6,000 after tax relief.
Frequently Asked Questions
No. Class 4 NI only applies to profits above the Lower Profits Limit of £12,570. If your profits are below this, you pay no Class 4 NI. Class 2 NI is now voluntary — but paying it (£3.45/week = £179.40/year) still protects your State Pension entitlement and access to contributory benefits, making it excellent value for most people.
No. As a sole trader, there is no legal distinction between you and your business. You cannot pay yourself a salary — instead you draw profit from the business. Everything in your business bank account is legally yours. If you want to pay yourself a tax-efficient salary and dividends, you would need to incorporate as a limited company.
You must keep records of all your business income and expenses for at least 5 years after the 31 January submission deadline for the relevant tax year. Records include invoices, receipts, bank statements, and mileage logs. HMRC can request these during an investigation. Making Tax Digital (MTD) for Income Tax will require quarterly digital record-keeping from April 2026 for profits above £50,000.
Missing the 31 January online deadline triggers an immediate £100 fixed penalty, even if you owe no tax. After 3 months, HMRC adds £10 per day (up to 90 days = £900). After 6 months, a further £300 or 5% of tax due (whichever is greater). Interest is also charged on any unpaid tax from the deadline date. Filing as quickly as possible after the deadline limits the damage.
At lower profit levels (under approximately £30,000), sole trader is usually simpler and similar in tax efficiency. Above £50,000–£60,000 profit, a limited company often becomes more tax-efficient because you can combine a small salary with dividend income, avoiding the higher rate of NI. However, limited companies have more administrative requirements (Companies House filings, corporation tax returns, director duties). Take specialist accountancy advice before incorporating.
Yes. If you work from home, you can claim either the HMRC flat rate (£26/month if you work more than 101 hours/month from home) or an apportioned share of actual costs (heating, electricity, broadband, mortgage interest or rent) based on the number of rooms used for business and the hours worked. The flat rate is simpler; actual costs may be higher but require more record-keeping.