UK Sole Trader Allowable Expenses: Complete List

UK sole traders deduct expenses against income to arrive at taxable profit. The rule under section 34 of the Income Tax (Trading and Other Income) Act 2005 is that expenses are deductible only if incurred 'wholly and exclusively' for the purposes of the trade. Mixed-purpose expenses must be apportioned; some categories have simplified flat-rate alternatives.

This guide covers the main expense categories, the wholly-and-exclusively rule, the simplified expenses option, and the record-keeping requirements.

The wholly and exclusively rule

Section 34 ITTOIA 2005 requires expenses to be incurred 'wholly and exclusively' for the trade. A purely business expense is fully deductible. A purely personal expense is not deductible at all. A mixed-purpose expense is normally not deductible at all under the strict rule, though some categories permit apportionment (vehicle use, use of home for business).

The 'duality of purpose' principle in case law (Mallalieu v Drummond 1983) holds that an expense with both business and personal purpose is generally not deductible, even where the business purpose is dominant. A self-employed solicitor's business suits were not deductible because they also served the personal purpose of being clothed.

Practical effect: clear business-only expenses (specialist tools, business insurance, professional fees) are fully deductible. Mixed-purpose expenses (a home office, a vehicle used for both business and personal trips) need apportionment under specific rules. Pure personal expenses (clothing, personal mobile phone, home utilities for non-business use) are not deductible.

Worked example: a sole trader buys a laptop for GBP 1,200 used 80% for business, 20% personal. The deductible portion is GBP 960 (80%). The same laptop used 100% for business would be GBP 1,200 deductible (subject to annual investment allowance rules for capital expenditure).

Travel and vehicle expenses

Business travel between sites, client visits, and trips for business purposes is deductible. Commuting from home to a regular workplace is not deductible (the workplace is treated as the equivalent of home for tax purposes).

Vehicle expenses: two options. Actual costs (fuel, insurance, MOT, repairs, depreciation) apportioned by business mileage, OR simplified mileage rates: 45p per mile for the first 10,000 business miles in a tax year, 25p per mile thereafter. Motorcycles 24p per mile. Bicycles 20p per mile. The mileage rates cover all running costs and are the simpler choice for most sole traders.

Public transport, taxis, rail and air for business purposes are fully deductible. Subsistence (meals away from base) is deductible at reasonable cost under specific HMRC guidance (BIM47705 onwards). Hotels for business travel are deductible.

Worked example: a self-employed consultant drives 12,000 business miles in a year. Mileage allowance: 10,000 * 45p + 2,000 * 25p = GBP 4,500 + GBP 500 = GBP 5,000 deductible. Plus GBP 800 of train fares for client visits, GBP 400 of business hotels. Total travel deduction GBP 6,200.

Premises and home office

Business premises (an office, shop, workshop) is fully deductible: rent, business rates, utilities, repairs and insurance. Where the premises is owned, mortgage interest is deductible (the principal is not). Capital improvements to owned premises are not income-deductible but add to base cost for CGT on disposal.

Home office: two methods. Actual costs apportioned by business use of the home (a percentage of utilities, rent or mortgage interest, council tax, repairs) - calculating the apportionment using a reasonable basis like floor area times time used. Simplified expenses: flat rate of GBP 10 a month for 25-50 hours business use, GBP 18 a month for 51-100 hours, GBP 26 a month for 101+ hours.

The simplified method is easier and HMRC-approved at the flat rates. The actual method may produce larger deductions for heavy home users with high utility bills but requires evidence and detailed calculation. Most occasional home-office users (under 25 hours) take a small actual amount or claim the relevant simplified rate.

Worked example: a sole trader works from home 40 hours a week, full-time. They claim GBP 26 a month simplified (GBP 312 a year) for the home office portion. Alternatively, computing actual: 10% of utilities (GBP 200), 10% of council tax (GBP 200), specific business-only broadband (GBP 360) = GBP 760. The actual method produces a higher deduction for this heavy user.

Equipment and capital allowances

Capital equipment (computers, machinery, tools, vehicles) is treated under capital allowances rules rather than income-expense rules. The Annual Investment Allowance (AIA) gives 100% first-year deduction on qualifying capital expenditure up to GBP 1 million a year. Most sole traders' equipment falls well within the AIA cap.

Under cash basis (default since April 2024), capital expenditure on plant and machinery is treated as expense when paid for sole traders, simplifying the calculation. Cars are not included in the cash basis capital treatment - cars use the standard capital allowances rules.

Cars used in the business are claimed under standard CA rules. A petrol car emits CO2 above 50g/km has 6% writing-down allowance; below 50g/km has 18%. Electric cars qualify for the first-year allowance at 100% under specific rules current to 2025. Personal use proportion is excluded.

Worked example: a self-employed designer buys a GBP 1,500 desktop computer (100% business use). Under cash basis the full GBP 1,500 is deductible in the year of purchase. Under accruals basis the same GBP 1,500 is deductible through AIA at 100%. The result is the same; the timing path differs slightly.

Professional and administrative expenses

Professional fees for the business are deductible: accountancy, legal fees, professional indemnity insurance, software subscriptions, bank charges on a business account, postal and courier costs. Professional body subscriptions where required for the trade (ICAEW, RICS, GMC) are deductible.

Marketing and advertising: website costs, business cards, online advertising, networking events with a clear business purpose, business gifts up to GBP 50 per recipient per year (above GBP 50 they become entertainment, which has different rules).

Communications: business mobile phone (or business proportion of personal mobile phone), business broadband (or business proportion), specific business landline. The wholly-and-exclusively rule applies to apportionment; reasonable estimation supported by evidence is acceptable to HMRC.

Employee costs: salaries, employer NI, pension contributions, payroll software, employee training. Director's salary in a limited company context, not relevant for pure sole trader (no employment relationship between trader and themselves).

Pre-trading expenses and post-cessation

Pre-trading expenses incurred up to 7 years before commencement of the trade can be deducted in the first year of trading under section 57 ITTOIA 2005. The expenses must be: incurred wholly and exclusively for the prospective trade, and would have been deductible if the trade had been in operation at the time. Common examples: market research costs, business plan preparation, professional fees on incorporation.

Post-cessation expenses incurred up to 7 years after cessation can be deducted under section 96A ITTOIA 2005, against other income in the year of expense. Common examples: bad debts written off after cessation, professional fees on closing the business, run-off liabilities not previously provided for.

Capital allowances rules apply to pre-trading capital expenditure as well, treating the asset as purchased on the first day of trading.

Practical action: keeping receipts and records of pre-trading expenses (even where uncertain whether the business will commence) preserves the deduction option. Where the business does start, the receipts support the claim.

Frequently asked questions

What expenses can a UK sole trader deduct?

Any expense incurred wholly and exclusively for the trade under section 34 ITTOIA 2005. Common categories: business premises costs, business travel and vehicle, equipment and tools, professional fees, marketing, communications, employee costs, business insurance. Mixed-purpose expenses need apportionment under specific rules (vehicle business mileage, home office hours). Pure personal expenses are not deductible.

How do I claim home office expenses?

Two methods. Simplified expenses: flat rate of GBP 10/18/26 per month for 25-50/51-100/101+ hours of monthly business use. Actual costs: a reasonable proportion of utilities, rent or mortgage interest, council tax, repairs, broadband. The actual method may produce larger deductions for heavy home-based traders but needs documented calculation. The simplified method is HMRC-approved and easier.

Can I claim mileage instead of actual vehicle costs?

Yes. Mileage allowance: 45p per mile for the first 10,000 business miles, 25p above. The allowance covers all running costs (fuel, insurance, MOT, repairs, depreciation). Most sole traders find the mileage allowance simpler than tracking actual costs. The choice is made for each tax year and stays consistent within that year. Records of business mileage (date, route, purpose) support the claim.

Are clothes a business expense?

Generally no for everyday clothing, even where worn for business. The Mallalieu v Drummond principle holds that clothes have a personal purpose (being clothed) regardless of business use. Specialist work clothing (safety boots, branded uniforms, costumes) is deductible. Cleaning of specialist work clothing is also deductible. Most office workers' clothing is not deductible.

How long must I keep expense records?

5 years 10 months after the SA filing deadline for the relevant tax year, under section 12B Taxes Management Act 1970. So for 2026/27 expenses, records must be kept until January 2033. Digital records are acceptable. Where HMRC opens an enquiry, the records support the claimed expenses; absence of records can result in disallowance of the claimed expenses on the trader's burden of proof.