The ‘Check Employment Status for Tax’ tool (CEST) is an online tool by HMRC which presents a series of questions in order to help determine your employment status for tax purposes, i.e. determine your IR35 status.

The CEST tool was developed for the off-payroll working rules introduced for the public sector in April 2017, in order to assist public sector bodies with determining their contractors’ IR35 status’ under the new rules. Whilst developed for the public sector, HMRC have encouraged its use in the private sector as well.

HMRC’s online IR35 tool, Check Employment Status for Tax (CEST) was previously named the Employment Status Service (ESS).