Allowable Business Expenses: What You Can Claim (and What HMRC Often Queries)

Knowing which business expenses, you can claim is essential for keeping your tax bill accurate and compliant. While the basic principle sounds simple, many business owners still feel uncertain about where HMRC draws the line. 

The key rule is that expenses must be wholly and exclusively for business purposes. Where costs are mixed between business and personal use, only the business element is normally allowable. 

Below is a practical guide to common allowable expenses, the areas HMRC often reviews more closely, and how to stay on the right side of the rules. 

Commonly Allowable Business Expenses 

Office and working from home costs 

If you run your business from home, you may be able to claim a proportion of household costs such as: 

• Electricity and heating 
• Broadband and telephone 
• Council tax and rent or mortgage interest (not capital repayments) 

Alternatively, sole traders can use HMRC’s simplified expenses flat rate for working from home, which avoids complex calculations. 

Limited companies must use an apportionment or a formal rental agreement approach, depending on circumstances. 

Travel and vehicle expenses 

Business travel is generally allowable when it is necessary for work and not ordinary commuting. 

Allowable costs may include: 

• Business mileage or actual vehicle running costs (depending on method chosen) 
• Public transport for business journeys 
• Parking fees and tolls related to business travel 

Travel between home and a permanent workplace is not usually allowable.

Staff costs 

Employers can usually deduct: 

• Wages and salaries 
• Employer National Insurance contributions 
• Pension contributions 
• Training costs related to the employee’s role 

Staff welfare expenses, such as modest staff gifts or staff events, are often allowable provided they meet the relevant tax rules. 

Professional fees and subscriptions 

Fees paid to accountants, solicitors, and other professional advisers for business purposes are normally allowed. 

Certain professional subscriptions are also deductible where they relate directly to the trade and appear on HMRC’s approved lists.

Marketing and advertising 

Most genuine marketing costs are allowable, including: 

• Website development and hosting 
• Online advertising 
• Branding and promotional materials 

Client entertaining is treated differently and is generally not tax deductible, even if it has a business purpose. 

Expenses HMRC Often Queries  

Mixed-use expenses 

Costs that have both personal and business use are one of the most common enquiry areas. Examples include: 

• Mobile phones 
• Vehicles 
• Home working costs 

HMRC will expect a reasonable and consistent apportionment, supported by evidence. 

Meals and subsistence 

Everyday meals are not normally allowable. Subsistence is generally only claimable where it is part of business travel outside the normal pattern of work. 

This is an area where claims are often challenged if they appear excessive or routine.

Clothing 

Ordinary clothing, even if worn for work, is not allowed. Only specialist clothing such as uniforms or protective wear qualifies. 

Repairs vs improvements 

Repairs to maintain an asset are usually allowable. Improvements that enhance or extend the life of an asset are normally capital in nature and treated differently for tax purposes. 

Record Keeping Matters 

Good records are essential. HMRC expects businesses to keep: 

• Receipts and invoices 
• Clear notes explaining business purpose 
• Consistent treatment year to year 

For self-employed individuals, records generally need to be retained for at least five years after the 31 January filing deadline. 

Poor records often lead to HMRC enquiries even where the underlying claim is reasonable. 

Claiming Correctly and Confidently 

Claiming allowable expenses is not about pushing boundaries. It is about: 

• Understanding what the rules allow 
• Applying them consistently 
• Being able to explain your position if asked 

When in doubt, conservative and well documented claims usually reduce risk. 

How Naylor Accountancy Services Can Help 

At Naylor Accountancy Services, we help business owners: 

• Review expenses to ensure they are allowable and correctly treated 
• Apply fair and defensible apportionments 
• Avoid common HMRC enquiry triggers 
• Keep clear, compliant records 

If you would like support reviewing your expenses or setting up a clearer system going forward, we are here to help. 

+44(0)1892 807 001
[email protected]