In the simplest terms, allowable expenses are costs incurred "wholly and exclusively" for business purposes. They are the costs that are incurred to generate income for your business.

Here’s a breakdown of the most common expenses that you, as a self-employed individual or small business owner, may be able to claim.

• Rent and Utility Bills - if you rent an office or workspace, you can claim for rent, business rates, and utilities such as electricity, heating, and water.
• Home Office - many self-employed individuals work from home. You can either claim a proportion of your household bills or a simplified flat rate that HMRC allow (£6 per week at the time of writing).
• Office Supplies - this includes items such as stationery, postage, printer paper, and any small equipment used in the daily running of your business. 

You can claim for uniforms or safety/protective clothing but not for normal clothes, even if you wear them to work.

You can claim for business-related travel, but not your daily commute to a regular place of work. Allowable travel expenses include:

• Vehicle Costs - if you use a car/van for business purposes, you can claim for fuel, insurance, servicing, and repairs. There are two ways to claim:


• Public Transport - train, bus, taxi, or plane fares can be claimed if they are for business purposes.
• Accommodation - if you travel for work and need to stay overnight, you can claim for reasonable hotel or accommodation costs, as well as meals incurred while away from home on business.

• Accountancy and Legal Fees - fees paid to accountants, solicitors, and other professional advisers can be claimed if they are related to your business.
• Bank charges - you can claim bank fees, such as charges on a business account or interest on loans used for business purposes.

Marketing and advertising are critical for growing your business, and expenses in this area are allowable. These include:

• Advertising in newspapers, online, or on social media.
• Website costs, including domain registration, hosting, and development.
• Costs for printing business cards, brochures, and promotional materials.
• Costs of supplying products to influencers in return for advertising. Note that this is also likely to be considered a sale of the product to the influencer.

• Subscriptions - you can claim for membership fees to trade bodies or professional organisations relevant to your industry, as well as subscriptions to professional magazines or journals.
• Training Courses - training that is directly related to your business or the work you do is allowable.

If you employ staff, you can claim the following as allowable expenses:

• Salaries - wages and salaries paid to employees, including bonuses, overtime, and statutory payments such as sick pay and maternity pay.
• Employer’s Pension Contributions
• Employer’s National Insurance Contributions
• Training Costs for Employees - training that is necessary to improve the skills and performance of your employees.

You will likely need to run a payroll scheme if you employ staff.

For businesses that sell products, the cost of stock, raw materials, and goods purchased for resale are allowable expenses. 

Business insurance premiums are allowable if they cover:

• Professional indemnity insurance.
• Public liability insurance.
• Employer’s liability insurance.
• Contents or vehicle insurance specifically for business assets.

While capital expenses, such as purchasing equipment or machinery, are not considered day-to-day business costs, you can claim capital allowances on these expenses. They are available on the cost of machinery, office equipment (e.g. computers and printers), and even some vehicles. The Annual Investment Allowance (AIA) allows most businesses to deduct the full cost of qualifying assets up to a limit each year.

Not all expenses are allowable, and some costs cannot be deducted for tax purposes. Common examples of non-allowable expenses include:

• Personal Expenses - any costs incurred for personal or family use are not deductible, even if some business-related activities take place during the same period. This includes clothing (unless it's protective clothing or a uniform) and your daily commute. If you have a limited company there are other tax consequences of the company paying for personal expenses so it’s best to keep these separate.
• Fines and Penalties - HMRC does not allow claims for fines or penalties, such as speeding tickets, even if they were incurred while carrying out business activities.
• Entertaining Clients - while you may incur costs for entertaining clients or business contacts, HMRC does not allow these for tax purposes.

To stay on the right side of HMRC, make sure that all expenses are legitimate business costs and keep detailed records and receipts to support your claims, as HMRC may request evidence during a tax review.