About IR35 Shield

Trusted expertise to keep you compliant

IR35 Shield was built by the development team at ContractorCalculator, who have 20 years’ experience of the contractor market and have followed IR35 since its inception in 1999.

The founder, Dave Chaplin, is a Master’s level mathematician, with 25 years commercial software development experience, primarily in the finance and legal sector. He is the author of the Contractors’ Handbook Third Edition and more recently IR35 & Off-Payroll Explained. He both assists with IR35 tax tribunals, regularly attends them to increase his knowledge, and has a wide network of contacts in the IR35 sphere including tax experts, lawyers and barristers. He has consulted on many occasions for HMRC, advises senior politicians and Government bodies on freelance tax matters, and is frequently quoted in both the trade press and national media, including the Financial Times, Telegraph, Guardian, The Times, and others.

Shield was developed with considerable input from employment law status experts and harnesses artificial intelligence (AI). The IR35 Assessment itself was first released on ContractorCalculator in 2009 and has since been used by over 100,000 contractors to assess their IR35 status.

We have the expertise to make sure your business and contractors stay fully compliant with IR35, reducing the risk of investigation and tax liabilities as a result.

Our team combines decades of software development experience with know-how in crucial areas such as employment case law and tax. This unique blend of expertise enables us to deliver an IR35 evaluation equivalent to that of an employment lawyer in under one second.

And with our network of established experts for you to choose from, you’re dealing with a compliance solution that offers a complete service.

The expert guide to contracting

ContractorCalculator was originally created in 1999 to help contractors navigate the IR35 tax legislation. It then evolved into a multifaceted resource hub and is now the UK’s leading website for the contingent workforce, regularly attracting over 200,000 visitors per month.

As well as a comprehensive range of free online financial, salary and tax calculators, we also provide expert industry commentary and analysis from our network of tax and industry leaders.

Keeping our finger on the pulse of the contracting sector has helped us to develop in-depth knowledge of IR35, which we harnessed to create this comprehensive compliance tool.

Contractor Calculator
over 100,000 assessments

Using our AI-driven assessment technology

over 25 years

Over 25 years software development experience

since 2009

Built in 2009 and expertly refined to align with latest IR35 legislation