Self-Employed Expenses UK 2026 — Complete Guide to Allowable Deductions

Getting your expenses right as a sole trader or self-employed person can save hundreds or thousands of pounds in tax each year. Claim too little and you overpay; claim the wrong things and you risk penalties. This guide covers every major category of allowable expense under HMRC rules for 2026/27, with practical examples and the clear lines you cannot cross.

The Core Principle: "Wholly and Exclusively"

Every allowable expense deduction for the self-employed must pass HMRC's fundamental test — the cost must be incurred wholly and exclusively for the purposes of the trade, profession or vocation.

This rule has three important implications:

1. Dual purpose kills the claim. If you buy a suit you wear to client meetings AND social events, HMRC will deny the whole cost — not just the social portion. There is no apportionment for dual-purpose items (with narrow exceptions for mixed-use assets like cars or premises).

2. Personal benefit matters. A meal alone when travelling for work may be allowable; a meal with your family at the same location is not.

3. Commercial rationale is required. Paying a family member above the market rate for their work does not make the excess payment deductible — only the market-rate amount is "wholly and exclusively" for the business.

Keep records for all expenses: invoices, receipts, bank statements. HMRC expects records to be retained for five years after the relevant Self Assessment filing deadline.

Category 1: Office and Administration Costs

Home office: If you work from home, you can claim either:

• Flat rate (simplified expenses): HMRC allows £10/month for 25–50 hours/month, £18/month for 51–100 hours/month, £26/month for 101+ hours/month — simple but often understates actual costs
• Actual costs method: Proportion of household bills (heat, light, broadband, rent/mortgage interest) using a consistent basis (e.g., number of rooms used for business as a fraction of total rooms, times hours used)

The actual method requires more record-keeping but can yield a much larger deduction — especially for heat and light, which rose significantly in 2022–24.

Category 2: Travel and Vehicles

Travel expenses for business journeys are allowable, but commuting to a regular workplace is never deductible — even for the self-employed.

The 24-Month Rule for Regular Workplaces

A workplace becomes a "permanent workplace" (non-deductible commute) after you have been attending it for a continuous period of 24 months where the attendance is expected to be more than 40% of your working time. Before this threshold, the journey is a deductible business travel expense.

This rule affects freelancers on long-term contracts: if you have worked at the same client site for over two years with no fixed end date in sight, your travel there is no longer deductible.

Approved Mileage Allowance Payments (AMAP)

Self-employed individuals using their own vehicle for business travel can claim at the following HMRC Approved Mileage Rates:

Example: A self-employed consultant drives 8,000 business miles per year. Claimable deduction: 8,000 × 45p = £3,600

This covers fuel, wear and tear, insurance, servicing, and depreciation — you cannot claim separate vehicle running costs if you use the mileage rate.

Alternatively, you can claim actual vehicle costs (fuel, insurance, road tax, servicing, MOT) plus capital allowances on the vehicle purchase, apportioned for private use. This method can be better for high-mileage diesel vehicles but requires detailed record-keeping.

Other deductible travel costs:

• Train and bus tickets (for business journeys)
• Taxis to meetings
• Parking (at meeting destinations, not at your own premises)
• Overnight accommodation for business trips (reasonable costs)
• Meals during overnight business trips (not day-trip meals unless you are away from home territory)

Congestion charge and ULEZ charges for business journeys are deductible. Parking fines and speeding tickets are never deductible (they are a personal penalty).

Category 3: Clothing

This is one of the most commonly misunderstood expense categories.

The principle: clothing must be protective or serve as a uniform/costume that you would not otherwise wear. A barrister's wig and gown are deductible; their everyday suit is not (confirmed by case law in Mallalieu v Drummond 1983, still the leading authority).

Category 4: Staff Costs

If you employ staff (even part-time), the following are deductible:

• Wages and salaries (at market rate — excess payments to family members are not allowable)
• Employer National Insurance contributions
• Employer pension contributions (defined contribution payments)
• Subcontractor costs (subject to CIS rules if in construction)
• Training directly related to current business activities (not for acquiring a new skill to set up a different trade)

Family member wages: You can pay a spouse, partner, or other family member a wage, and it is deductible — but only if the work is genuinely done and the rate is commercially justifiable. HMRC scrutinises this closely.

Category 5: Marketing and Advertising

Client entertaining — taking a client out for lunch, hosting an event — is specifically disallowed under HMRC rules for the self-employed, regardless of commercial purpose. This is one of the more frustrating restrictions and differs from the position for employees under some circumstances.

Category 6: Professional and Financial Costs

*Pension contributions are claimed separately via the pension relief mechanism — they reduce your Income Tax but are not a trading expense.

Note on finance costs: Interest on a business loan or overdraft is deductible. However, if you take a personal loan and use the funds in the business, you need to evidence the business use clearly. Interest on borrowing to buy a buy-to-let property is handled differently (subject to the Section 24 restriction for landlords).

Category 7: Capital Allowances

Capital items (assets lasting more than one year) are generally not deducted as expenses in the year of purchase — instead, you claim capital allowances.

Annual Investment Allowance (AIA)

The AIA allows 100% of the cost to be deducted in the year of purchase. The current AIA limit is £1,000,000 per year — which effectively means most sole traders can deduct the full cost of any equipment purchase immediately.

Applies to: Plant and machinery, tools, office equipment, IT equipment, commercial vehicles, fitted out premises (some fixtures).

Does not apply to: Cars (use capital allowances writing-down allowance instead — 18% per year main rate pool, 6% special rate pool for cars emitting >50g/km CO₂).

Full Expensing (Limited Companies Only)

From April 2023, limited companies can claim full expensing (100% first-year allowance) on qualifying new (not second-hand) plant and machinery. This does not apply to sole traders, who continue to use AIA.

Writing Down Allowance

For items that do not qualify for AIA (primarily cars) or where AIA has been exhausted:

• 18% per year (main rate pool) — most plant and machinery
• 6% per year (special rate pool) — integral features, high-emission cars

Simplified Expenses vs Actual Costs

HMRC allows sole traders to use simplified flat-rate expenses for three areas:

When simplified expenses are better: Low mileage, modest home office use, or when record-keeping burden is high.

When actual costs are better: High business mileage in an efficient car, significant home office use with high energy costs, or where actual costs are clearly higher than the flat rate.

You cannot mix and match on the same category year-to-year for the same asset — once you choose actual costs for a vehicle, you must continue with actual costs for that vehicle.

VAT on Expenses

If you are VAT-registered (mandatory above £90,000 turnover threshold for 2026/27), you can reclaim the VAT on business expenses. This effectively reduces the net cost of deductible expenses by 20%.

Key points:

• You need a valid VAT invoice (showing the supplier's VAT number, description, and VAT amount) to reclaim input VAT
• You cannot reclaim VAT on business entertainment, on employee's personal use, or on cars (with some exceptions for taxis and purely commercial vehicles)
• For mixed business/personal use, you can only reclaim the business-use proportion of VAT

What You Absolutely Cannot Claim

A non-exhaustive list of common disallowed expenses:

Practical Record-Keeping Tips

1. Use accounting software (FreeAgent, Xero, QuickBooks) from day one — it dramatically reduces the burden and improves accuracy
2. Scan receipts immediately (most apps have built-in receipt capture) — paper receipts fade and get lost
3. Maintain a mileage log — date, destination, business purpose, miles; apps like MileIQ can automate this
4. Separate business and personal finances with a dedicated business bank account
5. Review quarterly rather than scrambling at January 31st

Key Takeaways

• The "wholly and exclusively" test is the cornerstone of every allowable expense claim
• Travel is allowable but commuting is not; the 24-month rule can catch freelancers on long contracts
• Use AMAP rates (45p/25p for cars) for simplicity; switch to actual costs only if your vehicle-running costs are high
• Client entertaining is specifically disallowed — do not claim it
• Capital equipment up to £1,000,000/year can be fully expensed via the Annual Investment Allowance
• ISA and pension contributions are not trading expenses but reduce your overall tax bill separately

Calculate your self-employed tax with our self-employed tax calculator to see the impact of expenses on your final tax bill and National Insurance liability.