IR35 Status Checker

IR35 — formally the Intermediaries Legislation — determines whether a contractor working through a personal service company (PSC) should be taxed as an employee of the end client. If IR35 applies ('inside IR35'), the worker must pay income tax and National Insurance on their earnings as if they were an employee, removing much of the tax advantage of operating through a limited company.

HMRC and the courts assess IR35 status by examining the true nature of the working relationship, not merely the contract wording. Three factors carry the most weight in case law: substitution (whether the contractor has a genuine right to send a substitute), control (whether the client controls how, when, and where the work is done), and mutuality of obligation (whether there are ongoing obligations on both parties to offer and accept work).

Supporting factors — financial risk, use of own equipment, integration into the client's organisation, and exclusivity — provide additional evidence but are generally given less weight than the three primary tests. No single factor is determinative; HMRC and tribunals consider the overall picture.

Since April 2021, medium and large private-sector clients (and all public-sector bodies) have been responsible for making IR35 status determinations. This tool provides a weighted risk assessment across all eight key factors. It is not a substitute for a formal status determination or legal advice.