Evidence required to support business expense claims

Self-employed individuals can deduct allowable business expenses from their income when calculating taxable profits. However, businesses must keep accurate records and evidence to support the costs being claimed.

HMRC requires taxpayers to keep proof of business expenses, although evidence does not usually need to be submitted with a self-assessment tax return. Records should be retained and made available if HMRC requests them as part of a compliance check.

Evidence should show the nature of the expense, the amount paid and that the cost relates to the business. This may include receipts, invoices, bank statements, contracts or other supporting documents. Where an expense has both business and private use, records should also demonstrate how the business proportion has been calculated.

Allowable expenses can include costs such as office expenses, travel, insurance, marketing, professional fees, staff costs and business premises costs. However, personal expenses cannot be claimed, and only the business element of mixed-use costs can be deducted.

Businesses should also ensure they use the correct treatment for larger purchases. Under traditional accounting, equipment, machinery and vehicles may need to be claimed through capital allowances rather than as day-to-day expenses. Under the cash basis, most equipment and machinery can be deducted as an expense, although cars are generally dealt with through capital allowances.

Source:HM Revenue & Customs | 23-08-2026
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Aitch
I'm Aitch, the Founder and CEO of CIGMA Accounting Ltd. As a Chartered Management Accountant and as a CIMA member, I've spent more than 16 years helping businesses, entrepreneurs, landlords, and individuals with tax planning, accounting, and HMRC compliance. As a chartered accountant in London, I'm passionate about making complex tax matters easier to understand and helping clients make confident financial decisions. Over the years, I've advised start-ups, SMEs, established companies, and high-net-worth individuals across a wide range of tax and accounting matters. My expertise includes Corporation Tax, Self-Assessment, Capital Gains Tax, Inheritance Tax planning, R&D tax relief, capital allowances, international tax, and resolving complex HMRC compliance issues. Whether clients need a business accountant, tax accountant, or strategic tax advisor, my focus is always on delivering practical advice that creates long-term value. One of my specialist areas is Making Tax Digital (MTD). I've worked extensively with businesses preparing HMRC's digital reporting requirements, helping them move to cloud accounting, improve financial processes, and adopt technology that makes compliance more efficient. I regularly speak at Making Tax Digital roadshows, industry events, and educational sessions in collaboration with Zoho Books, sharing practical insights into digital accounting, tax legislation, and the future of the profession. Many business owners looking for the best accounting firm in London are not simply searching for an accountant they're looking for trusted advice, responsive support, and long-term value. That's the approach I've taken in building CIGMA Accounting. My team and I work closely with businesses across London and the UK, providing accounting services, tax advisory, bookkeeping, payroll, VAT, company accounts, and strategic tax planning tailored to each client's goals. Through this website, I share practical guidance on UK taxation, Making Tax Digital, HMRC updates, Corporation Tax, Self-Assessment, and business finance. My aim is to provide reliable, straightforward information that helps business owners understand changing regulations, reduce compliance risks, and make informed financial decisions with confidence.