Check Employment Status for Tax (CEST) is HMRC’s digital tool for determining whether someone is employed or self-employed for tax purposes.

Rebecca Seeley Harris has written a book called ‘CEST Explained‘ to do just that – explain CEST.  The CEST tool has been highly criticised mainly for HMRC’s interpretation of mutuality of obligations but, also for the ambiguity of the questions.  HMRC state, however, that they will stand by the determination of the tool as long as the input is accurate and used in accordance with HMRC’s guidance.  This book, therefore, hopes to demystify the CEST questions and provide the guidance given by HMRC, the result being that you should be able to answer it accurately.

In 2019-20 the CEST tool was used nearly 1 million times and over 51% of clients use the tool, so it is essential that the tool is used accurately by all.

This book is now available at

CEST Training

Rebecca also conducts training sessions on the CEST tool.  These are usually half-day sessions which can be arranged to suit.  These are small webinars so you can ask as many questions as you like in a confidential setting.

Please email to book a session or for further details: