Sole Trader Tax Return Guide for UK Tradespeople 2026: Self-Assessment, Expenses and Deadlines

Written by Tom Ellis · Senior Trades Editor

Last updated: July 2026

Quick Answer

UK sole trader tradespeople must complete a self-assessment tax return by 31 January each year (online) covering the previous tax year (6 April to 5 April). Your taxable profit is your total income minus allowable expenses — van costs, tools, insurance, PPE, and professional subscriptions all count. CIS deductions already paid reduce what you owe. Missing the January deadline triggers an automatic £100 fine.

For most tradespeople, the tax return is the most stressful admin task of the year. Done properly with accurate records, it can also produce a significant refund — particularly for CIS subcontractors. Done badly or late, it creates penalties, interest charges, and HMRC enquiries.

This guide explains everything a sole trader tradesperson needs to know about the self-assessment process in 2026 — including the deadlines, what expenses to claim, how CIS interacts with your return, and what Making Tax Digital means for you from April 2026.

Key Self-Assessment Dates for 2026

DateWhat Happens
6 April 2025Tax year 2025/26 begins
5 October 2026Deadline to register for self-assessment if new to it
31 October 2026Paper return deadline for 2025/26
31 January 2027Online return deadline + pay tax owed for 2025/26 + first 2026/27 payment on account
31 July 2027Second 2026/27 payment on account due

Allowable Expenses: What Tradespeople Can Claim

HMRC allows you to deduct business expenses from your income before calculating the tax you owe. Only "wholly and exclusively" business expenses qualify. For tradespeople, the most common allowable expenses are:

Tools and Equipment

Tools purchased for work are allowable. Small tools (under ~£300) can usually be claimed as a trading expense in full the year you buy them. Larger items of plant and equipment are claimed through Capital Allowances — typically the Annual Investment Allowance (AIA) which currently allows 100% deduction in year of purchase up to £1 million per year. Keep all receipts.

Van and Vehicle Costs

If the van is used exclusively for work, you can claim 100% of: fuel, road tax, insurance, MOT, servicing, tyres, and repairs. If you use it for private journeys too, you must apportion costs. Many sole traders use the simplified mileage rate instead: 45p per mile for the first 10,000 miles, 25p per mile after that — no need to keep receipts for every expense, just a mileage log.

Protective Clothing and Workwear

Hi-vis jackets, steel-toe boots, gloves, and safety helmets used for work are allowable. Clothing you could wear outside work (branded polo shirts, normal trainers) is generally not allowable even if you only wear them for work.

Insurance Premiums

Public liability insurance, employers' liability, professional indemnity, tools cover, and van insurance (business use portion) are all allowable expenses.

Professional Subscriptions and Qualifications

NICEIC, Gas Safe, NAPIT, CHAS, Construct Industry Training Board (CITB) levies, CSCS card fees, and trade body memberships are allowable. Training costs are allowable if they update existing skills — not if they are learning a completely new trade.

Other Common Allowable Expenses

How CIS Deductions Work on Your Tax Return

If you work as a CIS subcontractor, contractors deduct 20% (or 30% if you are unverified) from the labour element of your payments. These deductions are advance payments of your Income Tax and National Insurance. Here is how they flow through your return:

  1. Your total gross income appears as self-employment income on your return
  2. You deduct allowable expenses to calculate net profit
  3. Tax and NI are calculated on net profit
  4. CIS deductions already paid by contractors are offset against this bill
  5. If CIS deductions exceed your tax bill, HMRC refunds the difference

Many subcontractors receive a significant refund each year because the flat 20% CIS rate often overstates their actual tax liability once expenses are deducted. Keeping good records and filing promptly is the fastest route to receiving that refund. See our CIS tax guide for a full breakdown.

Payment on Account: The Second-Year Shock

When your self-assessment bill exceeds £1,000, HMRC collects advance payments toward next year's bill. This catches many tradespeople off guard in their second year of trading. If your 2024/25 tax bill was £3,000:

The practical advice: set aside 25–30% of every invoice payment into a separate account throughout the year. This covers both the balancing payment and payments on account without any panic at the January deadline.

Making Tax Digital for Sole Traders

Making Tax Digital (MTD) for Income Tax Self-Assessment (ITSA) is being rolled out in phases:

If you are already using accounting software or a bookkeeping app that integrates with HMRC (QuickBooks, FreeAgent, Xero), you may already be MTD-ready. If you keep records on spreadsheets or paper, you will need to switch to compatible software before your threshold applies.

Penalties for Late Filing and Late Payment

DelayPenalty
1 day late (filing)£100 automatic fine
3 months late£10/day for up to 90 days (max £900 additional)
6 months late5% of tax due or £300, whichever is higher
12 months lateA further 5% or £300
Late paymentInterest at Bank of England base rate + 2.5% from due date

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