IR35 basics for IT contractors

What IR35 is trying to decide

IR35 (off-payroll working rules) looks at whether a contractor is effectively working like an employee of the end client. If a role is Inside IR35, tax and National Insurance are usually deducted closer to employment rules. If it is Outside IR35, the contractor may operate through a limited company with different tax treatment — subject to the full working arrangements.

Status depends on the real working practices, not only what a job advert says. Factors often include control, substitution, and whether the contractor is part and parcel of the client organisation.

What to look for in job listings

On WEB JOBS, contract roles may show Inside or Outside IR35 where recruiters have provided it. Treat that as an important signal, then confirm details with the recruiter: who determines status, what the day rate includes, and whether the role is umbrella-only.

Ask early about notice periods, equipment, working hours, and whether you can send a substitute. Those practical details often matter as much as the headline rate.

Get advice before you commit

IR35 is a legal and tax topic. This guide is general information for jobseekers, not personal tax advice. If you are unsure, speak to an accountant who understands contractor work, and use official guidance from HMRC and ACAS when reviewing a specific engagement.