# Self Assessment expenses guide > Benefits & tax · Last updated 4 July 2026 Canonical HTML: https://moneyguide.org.uk/benefits-tax/self-assessment-expenses-guide/ Markdown mirror: https://moneyguide.org.uk/benefits-tax/self-assessment-expenses-guide.md ## Quick answer Self-employed workers and landlords claim allowable business expenses against income on Self Assessment — expenses must be wholly and exclusively for trade purposes. Self-employed workers and landlords claim allowable business expenses against income on Self Assessment. HMRC allows revenue expenses but not capital items, and poor records cause rejected claims. This guide lists common categories and the evidence you need. ## Key facts - Expenses must be wholly and exclusively for business — dual use needs apportionment - Capital items like laptops may qualify for annual investment allowance or full expensing - Simplified expenses offer flat rates for home, vehicle and mileage instead of actual costs - Keep receipts and bank records six years — HMRC can open enquiries within time limits ## Common categories Allowable categories include office costs, business travel, subsistence on work trips, professional fees, marketing and bank charges on your business account. Keep receipts for each category you claim. Clothing is allowable only if it is specialist uniform or protective equipment. Everyday clothes you wear for work are not deductible even if you only wear them for business. ## Home working Self-employed people can use the simplified £6 weekly flat rate for home working or calculate a proportion of bills based on room use and hours worked. Work out both methods and choose whichever gives the larger deduction. Employees working from home use different HMRC rules for employee expenses, not the self-employed simplified rates. Do not mix the two sets of rules on the same claim. ## Mistakes to avoid Do not claim personal meals, commuting to a regular workplace, or family salary without genuine work performed. HMRC routinely challenges these categories in enquiries. Mixing personal and business transactions in one bank account makes apportionment harder and increases the risk of errors. A separate business account is strongly recommended. ## Frequently asked questions ### When is first SA due? Register for Self Assessment by 5 October after the tax year in which you first need to file. Payment for that tax year is due by 31 January following the year end. ### Can I amend a return? Yes — you can amend online within 12 months of the filing deadline. Corrections after that period may require contacting HMRC directly. ### What about side hustles? The £1,000 trading allowance exempts small gross self-employment income without registering. Above that threshold, you must follow full expense rules or elect the allowance instead of deducting costs. ## Primary source https://www.gov.uk/expenses-if-youre-self-employed ## Related - [Self employment basics](https://moneyguide.org.uk/work-earnings/self-employment-basics/) - [Side hustle tax explained](https://moneyguide.org.uk/work-earnings/side-hustle-tax-explained/) --- Independent UK money guidance from [Money Guide](https://moneyguide.org.uk). Information only — not regulated financial advice.