- Sole traders pay both income tax and Class 4 National Insurance on profits above £12,570, calculated through Self Assessment each year.
- On £45,000 profit in 2025/26, the combined tax and NI bill is around £8,432, leaving roughly £36,568 in take-home.
- Missing the 31 January filing deadline triggers an automatic £100 penalty, with daily charges and interest added the longer the return is late.
Sole trader tax in the UK is made up of two charges on your profit: income tax and Class 4 National Insurance. For 2025/26, you pay no tax on the first £12,570, 20% basic rate up to £50,270, and 6% Class 4 NI on the same band. Most sole traders file once a year through Self Assessment with Sleek by 31 January, and miss-the-deadline penalties start at £100 the day after.
This guide covers the full picture for 2026: every rate, every threshold, a worked example at £45,000 profit, and the deadlines that actually matter.
What taxes does a sole trader pay in the UK?
Sole traders pay two charges on their business profit: income tax and National Insurance. Both are calculated and paid through one annual Self Assessment return, not through PAYE.
Income tax applies to profit above your Personal Allowance of £12,570. National Insurance comes in two classes for sole traders: Class 4, which is paid as a percentage of profit, and Class 2, which is now collected through Self Assessment alongside Class 4. Unlike employees, you work out both yourself and pay them in one bill.
The combined total is what catches first-year sole traders off guard. Once you understand how the two charges stack, the maths becomes straightforward.
What are the sole trader income tax rates for 2025/26?
Sole traders pay the same income tax rates as employees, but through Self Assessment rather than PAYE. The rates apply to your taxable profit, not your turnover.
Taxable profit band | Income tax rate | Band name |
£0 to £12,570 | 0% | Personal Allowance |
£12,571 to £50,270 | 20% | Basic rate |
£50,271 to £125,140 | 40% | Higher rate |
Above £125,140 | 45% | Additional rate |
Source: HMRC income tax rates and allowances for 2025/26.
Your Personal Allowance applies to your total income, not just your business profit. Rental income, employment income, and any other taxable income all count toward the same allowance. The allowance also tapers above £100,000 of total income and disappears completely at £125,140.
How does National Insurance work for sole traders?
Sole traders pay two classes of National Insurance: Class 4 on profits above £12,570, and Class 2 if profits exceed the Small Profits Threshold.
Class 4 NI is the main charge. You pay 6% on profits between £12,570 and £50,270, then 2% on anything above £50,270.
Class 2 NI changed at the 2024 Spring Budget. Sole traders with profits above the Small Profits Threshold of £12,570 no longer pay Class 2 as a separate weekly charge, though they still receive the National Insurance credits that count toward the State Pension. Those with profits below £6,725 can pay voluntary Class 2 contributions to protect their record.
NI class | Who pays | Rate | Profit threshold |
Class 4 (lower) | All sole traders | 6% | £12,570 to £50,270 |
Class 4 (upper) | All sole traders | 2% | Above £50,270 |
Class 2 (voluntary) | Below Small Profits Threshold | £3.45 per week | Profits below £6,725 |
If your profit sits below £6,725 and you want to keep building State Pension entitlement, voluntary Class 2 is usually the cheapest way to do it. Anyone earning above £12,570 gets the credit automatically.
How much tax will I pay on £45,000 profit?
On £45,000 profit in 2025/26, a sole trader pays roughly £8,432 in combined income tax and Class 4 NI. The breakdown is shown below.
Step 1: Work out taxable income
- Profit: £45,000
- Personal Allowance: £12,570
- Taxable income: £32,430
Step 2: Calculate income tax
£32,430 at 20% basic rate = £6,486
Step 3: Calculate Class 4 National Insurance
£32,430 at 6% = £1,946
Step 4: Total annual bill
- Income tax: £6,486
- Class 4 NI: £1,946
- Total: £8,432
That leaves you with approximately £36,568 after tax and NI. The effective rate on total profit works out at around 18.7%, because the Personal Allowance shelters the first £12,570 from both charges. Your marginal rate on every extra pound earned, however, is 26% once you cross the threshold.
Set aside 25% to 30% of every invoice in a separate account from day one. That covers your tax bill, your Class 4 NI, and your first payment on account without nasty surprises.
What are payments on account and why do they catch sole traders off guard?
Payments on account are advance instalments toward your next year’s tax bill, due in January and July. They are triggered automatically once your Self Assessment bill exceeds £1,000.
Each payment is 50% of your previous year’s tax bill. The first sits alongside your balancing payment on 31 January, and the second falls due on 31 July. So if your first-year bill was £2,000, your January payment is £2,000 (settling year one) plus £1,000 (first instalment for year two), totalling £3,000.
This is what creates the infamous January cashflow squeeze. New sole traders budget for the tax they owe but forget the advance payment due on the same date. Working with a sole trader accountant from Sleek means your bill is calculated months in advance, so you never get caught short.
Self Assessment deadlines every sole trader must know in 2026
Missing HMRC’s deadlines triggers automatic penalties, regardless of whether you owe any tax. The 31 January online filing date is the one that matters for most sole traders.
Deadline | Date | What it covers |
Register for Self Assessment | 5 October 2025 | First-time filers for 2024/25 |
Paper return filing | 31 October 2025 | 2024/25 tax year |
Online return filing | 31 January 2026 | 2024/25 tax year |
Balancing tax payment | 31 January 2026 | Tax owed for 2024/25 |
First payment on account | 31 January 2026 | 50% advance for 2025/26 |
Second payment on account | 31 July 2026 | Remaining 50% for 2025/26 |
If you have just started trading, you must register with HMRC by 5 October following the end of your first trading year. Our guide on how to file a Self Assessment return walks through the full process.
Which sole trader expenses can you claim?
Allowable expenses reduce your taxable profit, which reduces both your income tax and your Class 4 NI bill. Every £1,000 of legitimate expenses saves a basic-rate taxpayer £260 in combined charges.
The most commonly claimed sole trader expenses include:
- Office costs such as broadband, electricity, and a proportion of home utility bills if you work from home
- Travel including 45p per business mile for the first 10,000 miles, then 25p thereafter
- Professional fees like trade body memberships, software subscriptions, and your accountant’s invoice
- Marketing covering website hosting, advertising, and design work
- Equipment including laptops, tools, and machinery used for business
Our full breakdown of allowable sole trader expenses covers the categories most freelancers underclaim, including the rules around mixed-use items.
What is Making Tax Digital for Income Tax and when does it apply?
Making Tax Digital for Income Tax (MTD IT) is HMRC’s move to digital quarterly reporting for self-employed people and landlords. From April 2026, sole traders with qualifying income above £50,000 must use MTD-compatible software and submit quarterly updates instead of one annual return.
The thresholds taper down over the following years:
- April 2026: mandatory for qualifying income above £50,000
- April 2027: extended to qualifying income above £30,000
- April 2028: extended to qualifying income above £20,000
If you are anywhere near these thresholds, the switch involves more than software. Quarterly digital updates mean tighter bookkeeping habits and four submissions a year instead of one.
Our Making Tax Digital for Income Tax guide covers what changes, what software qualifies, and how to prepare.
What happens if you miss the Self Assessment deadline?
The day after the 31 January deadline, HMRC issues an automatic £100 penalty even if you owe no tax. Late penalties then escalate the longer the return remains outstanding.
Time after deadline | Penalty |
1 day | £100 fixed penalty |
3 months | £10 per day, up to £900 maximum |
6 months | Additional 5% of tax owed, or £300 minimum |
12 months | Further 5% of tax owed, or £300 minimum |
Unpaid tax | Interest charged at HMRC’s published rate |
Interest accrues on the tax itself, separately from the penalties. A return filed twelve months late with a £2,000 bill can rack up well over £1,000 in combined penalties and interest. HMRC accepts reasonable excuses for genuine emergencies, but “I forgot” is not one of them.
How Sleek helps with sole trader tax
Sleek handles the full sole trader tax process: bookkeeping, Self Assessment preparation, deadline management, and expert advice on allowable expenses. Our sole trader accountants calculate your bill quarterly so January never catches you off guard, and we file directly with HMRC on your behalf.
Whether you have just registered as self-employed or you have been trading for years, the goal is the same: pay the right tax, claim every allowable expense, and never miss a deadline.
Disclaimer: The preceding information is not legal advice. This content is aimed to provide general guidance. For more formal or legal advice, contact Sleek directly.
450,000
businesses worldwide.
from 4,100+ reviews.
satisfaction rate from
16,000 surveyed clients.
FAQs about sole trader tax in the UK
How much tax does a sole trader pay in the UK in 2026?
It depends on your profit. On £45,000 profit in 2025/26, a sole trader pays approximately £6,486 in income tax (20% on profit above the £12,570 Personal Allowance) and £1,946 in Class 4 National Insurance — a total of around £8,432. Higher-rate tax at 40% applies to profits above £50,270. All figures are based on HMRC’s 2025/26 rates.
What is the sole trader tax rate in the UK?
Sole traders pay the same income tax rates as employed workers: 0% on the first £12,570 (Personal Allowance), 20% on profit from £12,571 to £50,270, 40% on profit from £50,271 to £125,140, and 45% above £125,140. On top of income tax, sole traders also pay Class 4 National Insurance: 6% on profits between £12,570 and £50,270, and 2% above £50,270. Source: HMRC 2025/26.
Do sole traders pay National Insurance?
Yes. Sole traders pay Class 4 National Insurance — 6% on profits between £12,570 and £50,270, and 2% on profits above that. Class 2 NI is also relevant for sole traders above the Small Profits Threshold of £12,570; since 2024/25, this is collected via Self Assessment rather than as a separate standing charge. Paying NI protects your entitlement to the State Pension and certain benefits.
What is the sole trader tax-free allowance?
The Personal Allowance for 2025/26 is £12,570. You pay no income tax on the first £12,570 of profit. However, National Insurance applies separately from a lower threshold — so sole traders with profit below £12,570 may owe no income tax but could still have Class 2 NI obligations. The Personal Allowance reduces above £100,000 total income and disappears at £125,140. Source: HMRC.
When do sole traders pay tax?
The main payment deadline is 31 January following the end of the tax year. If your bill exceeds £1,000, you also make two payments on account: the first on 31 January (alongside your main bill) and the second on 31 July. This means your first January as a filing sole trader may involve both settling last year’s tax and paying an advance on next year’s. Source: HMRC.
View more
Do I need to register for Self Assessment as a sole trader?
Yes. If you are self-employed as a sole trader and your income exceeds £1,000 in a tax year, you must register for Self Assessment with HMRC. The registration deadline is 5 October following the end of your first trading year. You then file annually. Missing registration can lead to late filing penalties even if you owe no tax. Source: HMRC.
Can I reduce my sole trader tax bill?
Yes — through allowable business expenses. Costs such as office use, travel, professional subscriptions, marketing, and accountancy fees can all be deducted from your profit before tax is calculated. Reducing your taxable profit by £5,000, for example, saves £1,000 in income tax (at the basic rate) and a further £300 in Class 4 NI.
See our guide to sole trader expenses you can claim for the full list. If you are weighing whether a limited company structure would reduce your overall tax, read our sole trader vs limited company comparison.
