IR35 Checker
Answer 10 questions about your contractor engagement to get a quick indication of whether you are likely inside or outside IR35. Each question covers a key factor HMRC uses when assessing off-payroll working status.
Frequently asked questions
What is IR35 and how does it affect contractors?
IR35 is off-payroll working legislation introduced in 2000. It targets contractors who work like employees but operate through an intermediary (typically a limited company) to pay less tax. If HMRC determines your engagement falls inside IR35, you are taxed as an employee on that income — paying income tax and National Insurance at employment rates, with none of the tax advantages of a limited company.
What is the HMRC CEST tool and should I use it?
CEST (Check Employment Status for Tax) is HMRC's own online IR35 tool. It can be useful because HMRC says it will stand behind results produced by CEST — provided you answer the questions accurately and in good faith. However, CEST has been criticised for not covering every scenario (particularly mutuality of obligation) and returning a high rate of "cannot determine" results. Use it alongside professional advice.
What are the consequences of getting IR35 wrong?
For engagements where you are the deemed employer (private sector since April 2021, public sector since 2017), getting the determination wrong can result in unpaid income tax and NI plus interest and penalties. Since the Off-Payroll Working rules shifted responsibility, end-clients or agencies are liable for the tax in many cases — but contractors can still face consequences if they have provided misleading information.
Who determines my IR35 status?
Since April 2021, for medium and large private sector clients (and all public sector clients since 2017), the end-client is responsible for issuing a Status Determination Statement (SDS). Small companies (those meeting two of: under £10.2m turnover, under £5.1m on balance sheet, under 50 employees) are exempt and the contractor remains responsible for their own determination. HMRC can challenge any determination they believe is incorrect.
Related tools
Whether inside or outside IR35 — InvoiceAdept handles your invoicing
Create compliant invoices, get paid faster, and keep a clear record of every transaction. Built for UK contractors and the self-employed.
Start free trial