Self Assessment allowable expenses: SA103 boxes 11 to 19 explained

On a UK Self Assessment tax return, sole traders report their business income and allowable expenses on the Self-Employment supplementary pages (SA103). Under section 34 of the Income Tax (Trading and Other Income) Act 2005 (ITTOIA 2005), an expense is allowable only if it is incurred wholly and exclusively for the purposes of the trade.

When you file online for the 2025 to 2026 tax year (due by 31 January 2027), HMRC's form asks you to sort your day-to-day running costs into specific expense boxes. Knowing which receipts belong in which box — and which costs must be left out altogether — prevents last-minute guesswork in January.

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Box-by-box guide to SA103S allowable expenses (Boxes 11 to 19)#

On the short form (SA103S), enter only the allowable business amount in Boxes 11 to 19. Leave out any private share of a cost (see how to split receipts between business and personal use).

Box 11: Costs of goods bought for resale or goods used#

What goes here: Raw materials, stock bought for resale, and direct costs of producing goods.

• Typical receipts: Trade supplier invoices, timber, plumbing or electrical parts for a client job, wholesale stock invoices, cafe ingredients, packaging materials.
• Record tip: If you took stock for your own personal or family use, do not include the cost of those items in your allowable expenses.

Box 12: Car, van and travel expenses#

What goes here: Business motoring costs and business travel away from your normal place of work.

For cars, vans and motorcycles, you have two ways to claim:

1. Simplified expenses (flat rate per business mile): Claim a flat rate for each business mile driven instead of tallying up fuel, insurance and servicing receipts.
   • For the 2025 to 2026 tax year (return due 31 January 2027): Cars and goods vehicles are claimed at 45p per mile for the first 10,000 business miles (25p per mile after 10,000 miles).
   • From 6 April 2026 (the 2026 to 2027 tax year): The first-10,000-mile rate for cars and goods vehicles is 55p per mile (25p per mile after 10,000 miles).
   • Motorcycles: 24p per mile across all business miles.
2. Actual vehicle running costs: Total your fuel, road tax (VED), vehicle insurance, breakdown cover, servicing, repairs and MOT receipts, then claim only the business-use percentage supported by your mileage records. Parking, tolls and congestion charges incurred on business journeys can be claimed separately alongside the flat rate.

Box 12 also covers non-vehicle business travel: train, bus, tube, air and taxi fares for business journeys, hotel room costs on overnight business trips, and meals on overnight business trips.

• What does NOT go in Box 12: Everyday commuting between your home and a regular place of business, parking fines, speeding penalties, or the private share of motoring expenses. See self-employed mileage and vehicle records.

Box 13: Wages, salaries and other staff costs#

What goes here: Gross wages and salaries paid to employees, employer National Insurance contributions, employer pension contributions, agency staff fees, and subcontract labour costs (HMRC's SA103S notes count subcontract labour costs here on the short form).

• Important: Never include your own drawings (money you take out of the business for yourself). Sole traders are taxed on business profit, so payments to yourself are not a deductible wage expense.

Box 14: Rent, rates, power and insurance costs#

What goes here: Costs of running your business premises — or the allowable share of your home running costs if you work from home.

• For dedicated business premises: Commercial rent, business rates, water, heating, lighting, property insurance, security and building contents cover.
• For working from home: Either HMRC's simplified monthly flat rate (£10 a month for 25 to 50 hours, £18 a month for 51 to 100 hours, or £26 a month for 101+ hours a month) or an apportioned share of your actual household utility bills. See our full guide to working from home expenses for sole traders.

Box 15: Repairs and maintenance of property and equipment#

What goes here: Maintenance and repairs that restore business premises, tools, or equipment to their working condition without materially improving them. Under the cash basis (the default for most sole traders since 6 April 2024), routine purchases of tools, laptops, office furniture and machinery used in the business are also claimed as allowable expenses (cars remain excluded and use capital allowances or mileage rates).

• Typical receipts: Repairing a broken workshop tool, replacing worn parts on a laptop, repainting a rented studio, or replacing hand tools.

Box 16: Accountancy, legal and other professional fees#

What goes here: Fees paid to accountants, bookkeepers, solicitors, surveyors, architects or debt collection agencies wholly for your trade.

• What is excluded: Legal fees for buying land or buildings (under traditional accounting), fines for breaking the law, or professional costs for settling personal tax disputes unrelated to routine trading accounts.

Box 17: Interest and bank and credit card financial charges#

What goes here: Bank charges on a business account, business credit card charges, overdraft interest, hire purchase interest, and payment processor or card-machine fees (such as Stripe, Square, SumUp or PayPal fees).

• Cash basis note: Following the Finance Act 2024 reforms (from the 2024 to 2025 tax year onwards), the former £500 cap on cash-basis interest deductions was abolished. Interest on a loan used wholly and exclusively for the business is deductible in full under the cash basis.

Box 18: Phone, fax, stationery and other office costs#

What goes here: Day-to-day administrative and communication costs, including small office equipment and computer software.

• Typical receipts: Business mobile phone bills, the business-use proportion of your home broadband and landline, postage, couriers, printer ink, paper, stationery, small office equipment, and computer software subscriptions (cloud storage, design tools, accounting software, domain names and web hosting).
• Important WFH rule: HMRC's simplified working-from-home flat rate (claimed in Box 14) does not include telephone or internet expenses. You can still claim the business proportion of your phone and broadband bills here in Box 18 alongside the working-from-home flat rate.

Box 19: Other allowable business expenses#

What goes here: Genuine trade expenses that do not fit into Boxes 11 to 18.

• Typical receipts: Advertising and marketing (website ads, flyers, directory listings), trade body or professional subscriptions approved as wholly for the trade, trade journals, protective clothing (hi-vis vests, steel-toe boots) or branded uniforms.

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How SA103S Boxes 11 to 19 map to SA103F (Full form)#

If your turnover is £90,000 or more and you file SA103F, the form splits out subcontractors, advertising and bank charges onto separate lines:

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Five expenses sole traders commonly try to claim (that HMRC disallows)#

Even when you have a valid receipt paid from a business bank account, HMRC disallows certain expenses by statute or case law:

1. Client entertaining and hospitality (s. 45 ITTOIA 2005; BIM45000): Taking a client, prospective client or supplier out for coffee, lunch, dinner or an event is 0% deductible for Income Tax, and input VAT cannot be reclaimed.
2. Everyday clothing (Mallalieu v Drummond [1983] 2 AC 861): Ordinary clothes worn solely at work — such as a business suit, smart shoes, or plain black trousers — are disallowed because they also serve the human need for warmth and decency. Only protective clothing (hard hats, safety boots, overalls) or uniforms and costumes are allowable.
3. Ordinary commuting: Travel between your home and a regular base of operations (such as a rented studio, shop, office or long-term site) is private travel, not business travel.
4. Fines and penalties: Parking tickets, congestion-charge penalty notices, speeding fines and late-filing tax penalties are never deductible.
5. Your own drawings (personal pay): As a sole trader, you and the business are the same legal person. Money you transfer to yourself for living costs is drawings from profit, not an allowable wage expense.

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Pre-filing checklist for your SA103 expenses#

• Check the tax year dates: Confirm all receipts and invoices fall within the 6 April to 5 April tax year you are filing.
• Pick one vehicle method: Check whether you are claiming simplified expenses (flat rate per mile) or actual running costs for your vehicle — do not claim both for the same vehicle.
• Use the right mileage rate for the year: 45p per mile (first 10,000 miles) for 2025–26 returns due 31 January 2027; 55p per mile for journeys from 6 April 2026.
• Strip out private use: Remove any private share of phone, broadband, utility and mixed shop receipts before entering figures in SA103S Boxes 11 to 19.
• Leave out disallowed expenses: Exclude all client entertaining, ordinary clothing, commuting and parking fines.
• Match your VAT basis: If you are VAT-registered and accounting net of VAT, enter expenses excluding reclaimable VAT; if not VAT-registered, enter figures including VAT.
• Retain the records: Keep the digital or paper receipts and mileage records for at least 5 years after 31 January.