What Business Expenses Can I Claim?
Most guides answer this with a list of categories — office costs, travel, insurance — which tells you almost nothing when you’re holding a receipt and wondering about this purchase. The real test is whether the cost was incurred wholly and exclusively for your business. This page explains that rule, the three things people most often claim wrongly, how large purchases are treated differently, and then lets you check any specific expense against HMRC’s own guidance.
The rule that decides almost everything
An expense is allowable if it’s incurred wholly and exclusively for the purposes of your business. That’s it — that single test settles most questions.
Where it gets awkward is mixed use. If something serves both business and personal purposes, you can only claim the business proportion, and you need a reasonable basis for the split. HMRC’s own example: a £200 annual phone bill, of which £70 is business calls, means you claim £70. Same principle for a home office — apportion by rooms used, or by time.
There’s no category list that can answer this for you, because two businesses buying the identical item can get different answers depending on how it’s used.
The three things people get wrong
Client entertainment is never allowable. Taking a client to lunch, drinks, events, hospitality — not deductible for UK businesses. This is one of the most common errors on Self Assessment returns. Staff entertainment is treated differently, and business gifts have their own narrow rules.
Everyday clothing isn’t claimable — even if you only wear it for work. The exceptions are genuine protective clothing, uniforms, and costumes.
Your commute isn’t business travel. Travel between home and your regular workplace is personal. Travel to a client site, or between work locations, generally is claimable.
Big purchases work differently: capital allowances
If you buy equipment, a van, or machinery, you’re usually not claiming it as a simple expense — it goes through capital allowances, a separate mechanism.
Annual Investment Allowance (AIA) lets you deduct 100% of qualifying plant and machinery in the year you buy it, up to £1 million per accounting period. That limit is permanent. For most small businesses this means big purchases are effectively fully deductible in year one.
Writing Down Allowances (WDA) apply where AIA doesn’t — spending above the limit, or assets that don’t qualify. The main pool rate fell from 18% to 14% from April 2026; the special rate pool is 6%. A new 40% First Year Allowance was introduced from January 2026 for qualifying main-rate plant and machinery.
Cars are the big exception — they don’t qualify for AIA, and are handled through writing-down allowances at rates driven by CO2 emissions. Vans generally do qualify for AIA.
Capital allowances changed in 2026 — if you’re working from older guidance, check the rates are current.
Read the full guide: Capital allowances explained →
Check a specific expense
The answer always depends on how you use the item, but here’s where the detail lives. Each of these 74 expenses has its own page with separate answers for sole traders, limited companies and employees, grounded in HMRC guidance.
Office & Home Working
Travel & Mileage
Equipment & Technology
Professional Fees
Insurance
Training & Development
Vehicles
Clothing & Uniform
Food & Subsistence
Entertainment
Marketing & Advertising
Pensions
Staff Costs
Not sure where yours fits?
Search all 74 UK business expenses in the checker.
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The wholly-and-exclusively test and the treatment of allowable expenses are set out in GOV.UK’s guidance for the self-employed. AIA is £1m per accounting period, made permanent in 2023. Main-pool WDA reduced from 18% to 14% from 1 April 2026 (Corporation Tax) / 6 April 2026 (Income Tax); special rate pool 6%. A 40% First Year Allowance for qualifying main-rate plant and machinery applies from 1 January 2026. Full expensing (100%, uncapped) is available to companies on new, non-car main-rate assets. Last checked 14 September 2026.