Claiming the right business expenses is one of the practical ways founders can reduce their tax liability legitimately — but many either overclaim and risk HMRC scrutiny, or underclaim and pay more tax than necessary. Understanding what counts as an allowable business expense, and what does not, is a fundamental part of managing a business's finances and tax obligations correctly.
An allowable business expense is a cost that has been incurred wholly and exclusively for the purposes of the business and can therefore be deducted when calculating taxable profit. Common categories include office and equipment costs, business travel and accommodation, professional fees, marketing and advertising, insurance, and staff costs. HMRC provides guidance on what qualifies, and some costs — such as those with both personal and business elements — require a reasonable apportionment rather than full deduction.
The rules on allowable expenses differ between sole traders and limited companies, and some categories — such as home working costs, vehicle use, and entertaining — have specific rules that are easy to misapply. When in doubt, keeping the receipt and asking your accountant is preferable to assuming something qualifies or leaving it out. Our guide to business expenses for UK founders explains the key categories and common pitfalls.