IR35 Tools and Resources
Use our IR35 tools to check employment status, work out who is responsible for making the decision and compare the financial impact of inside and outside IR35. Below the tools you will also find official HMRC guidance, legislation, case law sources and specialist reference material.
Our IR35 tools
- IR35 Status Checker – assess the main employment status factors and see whether an engagement is more likely to fall inside or outside IR35.
- IR35 Responsibility Checker – find out who makes the IR35 decision, whether the client must issue an SDS and which organisation may have to deduct PAYE and National Insurance.
- IR35 Clause and Reality Checker – paste a clause, compare the wording with what happens in practice and get guidance on points worth checking, useful evidence and possible inconsistencies.
- Inside vs outside IR35 calculator – compare estimated take-home pay for an outside IR35 limited company contract with an umbrella engagement.
Practical IR35 resources
- IR35 case law library – summaries of the main IR35 and employment status decisions, with links to the underlying judgments where available.
- IR35 contract clause examples – practical examples covering substitution, control, mutuality and other common status clauses.
Official HMRC resources
- CEST (Check Employment Status for Tax) – HMRC’s own status tool. Updated April 2025.
- Off-payroll working guidance – official explanations, examples and responsibilities.
- HMRC engager guidance – responsibilities and documentation for clients.
- Employment Status Manual (ESM) – HMRC’s internal reference material on employment status and IR35.
- ESM10000+ IR35 guidance – the main IR35 and off-payroll section within the ESM.
Legislation and official legal sources
- Chapter 8, ITEPA 2003 – the original intermediaries legislation.
- Chapter 10, ITEPA 2003 – the off-payroll working rules for public sector clients and medium or large private sector clients.
- The National Archives case law service – official UK judgments and tribunal decisions.
- BAILII – searchable database of UK and Irish case law, including older employment status and tax cases.
Professional bodies and tax commentary
- Chartered Institute of Taxation – technical tax commentary, policy updates and professional analysis.
- ICAEW Tax Faculty – professional tax guidance and commentary for advisers and businesses.
- Accountancy Daily – commentary on tax cases, tribunals and HMRC updates.
Other IR35 tools and services
- IR35 calculator (ITContracting) – works out the cost of inside and outside IR35 under the original Chapter 8 rules.
- IR35 Status Review (Qdos) – professional contract and working practices review.
Independent IR35 experts and guidance sites
- Qdos – long-standing IR35 specialists offering insurance, reviews and status advice.
- Brookson Legal – a regulated law firm focused on IR35 and off-payroll compliance.
- IPSE – policy, research and support for self-employed people affected by IR35.
- ContractorCalculator – long-running IR35 commentary, guides and contractor-focused analysis.
Contract templates and documentation
- IR35-friendly contract templates (Qdos) – free model contract templates.
- IR35 Shield – contract template packs and reviews.
- IPSE contract templates – downloads available for members.