Going self-employed is one of the most significant financial decisions a person can make — and it comes with a tax responsibility that most people underestimate until the first Self Assessment deadline arrives. Unlike employment, where tax is deducted automatically through PAYE, self-employment means you are personally responsible for calculating, reporting, and paying every penny you owe to HMRC.

Get it right and you keep significantly more of what you earn. Get it wrong and you face penalties, interest, and the stress of an HMRC enquiry.

This guide covers the essential tax obligations every UK sole trader and freelancer needs to understand in 2026 — and where working with a specialist accountant for self-employed individuals consistently makes a measurable financial difference.

Registering as Self-Employed: The First Step Most People Delay

If you start working for yourself — whether full-time or alongside employment — you must register with HMRC as self-employed. The deadline is 5 October following the end of the tax year in which you started trading. So if you began freelancing in June 2025, you needed to register by 5 October 2025.

Failing to register on time carries penalties. HMRC does not send reminders, and "I didn't know" is not accepted as a reasonable excuse.

Registration is done through HMRC's online portal, after which you'll be required to file a Self Assessment tax return every year — even in years where your profit falls below the tax-free Personal Allowance.

If your business has grown to the point where you're questioning whether to remain a sole trader or move to a limited company structure, our team can model the tax position for both and help you make the right call. Company formation services are available through Hayes if incorporation is the right next step.

What Tax Do Self-Employed People Pay?

As a sole trader, you pay two types of tax on your profits: Income Tax and National Insurance Contributions (NICs).

Income Tax on Self-Employment Profits (2025/26):

• Personal Allowance — £12,570 (0% tax)
• Basic Rate — 20% on profits between £12,571 and £50,270
• Higher Rate — 40% on profits between £50,271 and £125,140
• Additional Rate — 45% on profits above £125,140

National Insurance for the Self-Employed (2025/26):

• Class 2 NICs — abolished from April 2024. Previously a flat weekly charge, this has now been removed entirely for most self-employed people
• Class 4 NICs — 6% on profits between £12,570 and £50,270, then 2% on profits above £50,270

So a sole trader earning £45,000 profit in 2025/26 would pay Income Tax and Class 4 NICs on earnings above £12,570 — with the exact figure depending on any other income, pension contributions, or reliefs in play. Getting an accurate tax estimate before the January deadline is exactly what Self Assessment support from Hayes delivers.

Allowable Expenses: The Single Biggest Way to Reduce Your Tax Bill

Your taxable profit is not your turnover — it's your turnover minus your allowable business expenses. Every allowable expense you miss is profit you're paying tax on unnecessarily.

Commonly allowable expenses for sole traders and freelancers:

• Office costs — stationery, printer ink, postage, equipment
• Travel — business mileage (45p per mile for the first 10,000 miles), train, bus, parking (not commuting to a regular employer)
• Marketing — website costs, advertising, business cards, social media tools
• Professional fees — accountancy, legal advice directly related to the business
• Software and subscriptions — tools used for the business (project management, design software, communication platforms)
• Phone and internet — the business-use proportion of your bills
• Clothing — only specialist protective clothing or uniforms; not general clothing you could wear outside work
• Training — courses and qualifications that develop existing skills for your current work (not retraining for a different career)
• Home office costs — if you work from home, a proportion of household bills (heat, electricity, broadband) can be claimed, or the flat rate of £6 per week without receipts

The Trading Allowance: If your gross self-employment income is £1,000 or less in a tax year, you don't need to declare it or pay tax on it. Above that, you must file.

Bookkeeping and accounting services from Hayes ensure your expense records are accurate, complete, and HMRC-ready throughout the year — not scrambled together at year-end.

Payments on Account: The Tax Bill Nobody Warned You About

The most common shock for first-time Self Assessment filers is not the tax bill itself — it's Payments on Account.

If your tax bill exceeds £1,000, HMRC requires you to make advance payments toward the following year's tax. These are due:

• 31 January — first payment on account (50% of previous year's bill) due alongside your balancing payment
• 31 July — second payment on account (the other 50%)

This means in your first year of significant self-employment income, you may face a tax bill of up to 150% of what you expected — your actual liability plus the first payment on account, all due in January.

Understanding this in advance allows you to set money aside throughout the year rather than facing a cashflow crisis in January. Our tax advisory team calculates your expected liability before year-end so there are no surprises.

VAT: When You Need to Register and What It Means

If your taxable turnover exceeds £90,000 in any rolling 12-month period, VAT registration becomes mandatory — not optional. You must register within 30 days of crossing the threshold.

Many self-employed people also choose to register voluntarily below the threshold, particularly if their clients are VAT-registered businesses who can reclaim input VAT. Voluntary registration allows you to reclaim VAT on your own business purchases, which can be meaningful for freelancers with high software, equipment, or travel costs.

VAT return services from Hayes cover registration, scheme selection (standard, flat rate, cash accounting), and ongoing quarterly return preparation and submission.

Making Tax Digital: What Self-Employed People Need to Know in 2026

Making Tax Digital for Income Tax is already live for self-employed individuals with qualifying income above £50,000. The threshold drops to £30,000 in April 2027 and £20,000 in April 2028 — meaning the majority of sole traders will eventually be required to keep digital records and file quarterly updates to HMRC.

If you're already in scope, our Making Tax Digital service handles everything from software setup to quarterly submissions. If you're approaching the threshold, now is the time to prepare rather than scramble when the letter from HMRC arrives.

How Hayes Chartered Certified Accountants Supports the Self-Employed

At Hayes, we believe in being more than just accountants — we are your gateway to financial clarity and success. For self-employed professionals, that means a fixed-fee, fully managed service that covers registration, annual Self Assessment, expense review, tax planning, VAT, and MTD — all handled by our ACCA-certified team of 100+ professionals, with no hidden charges and a money-back guarantee.

Whether you're a contractor, a startup founder, or an established small business owner ready to professionalise your finances, the conversation starts with a free consultation.

Book your free 15-minute consultation with Hayes →

📞 020 8646 0800 | 💬 WhatsApp: 07429 584 191 | 📧 info@hayes-accountants.co.uk