As a sole trader you're taxed on profit, not turnover - so every legitimate expense you claim comes straight off your tax bill. For most sole traders paying basic-rate income tax plus Class 4 National Insurance, £100 of expenses saves £26. For a higher-rate taxpayer, it's £46. Our guide to how much tax to set aside shows what that means for the money you put by. Yet we see the same two problems again and again: people under-claiming because they didn't know a cost qualified,

HMRC taxes your rental profit, not your rent. That means every allowable expense you claim comes straight off your tax bill - a £1,000 expense saves a basic-rate taxpayer £200, and a higher-rate taxpayer £400. Yet we regularly see landlords doing one of two things: under-claiming and paying more tax than they need to, or over-claiming and risking an HMRC challenge. This guide sets out exactly what you can and can't claim, where the tricky lines fall, and what records HMRC exp