Don't fail an HMRC check: capital vs revenue, and the errors they look for

The two mistakes HMRC flags most on landlord returns are capital-vs-revenue and replacement relief. This checker helps you get both right.

Built around HMRC's own Property Rental Toolkit, this tool tackles the errors that trigger enquiries. The biggest is treating a capital improvement as a repair — a new extension is capital, fixing the roof is revenue — and claiming it in full against your rent.

A capital-vs-revenue classifier tells you which is which, a replacement-of-domestic-items calculator works out the like-for-like amount you can actually claim (the old 10% wear-and-tear allowance is long gone), and a reference list separates what's allowable from what isn't.

It also lists the common errors HMRC looks for — from claiming the full mortgage interest instead of the 20% Section 24 credit, to initial repairs on a run-down purchase — so you can sense-check your return before you file.

Who it's for: any landlord filing their own self-assessment who wants to avoid a costly enquiry.

Educational guidance only — not financial, tax or legal advice. Tax and property rules change; always verify current figures on GOV.UK and take professional advice before acting. © 2026 Property Clues.