Quick summary: ir35guide.co.uk is an independent UK contractor tax resource built by James Crawford. All content is based on published HMRC guidance and UK tax legislation. This site provides general information only — it is not professional tax advice.
James Crawford is the author and publisher of ir35guide.co.uk. He built this site and its calculators to provide UK contractors with free, accessible information about IR35 and contractor tax rules.
All content on this site is based on:
Tax rates, National Insurance thresholds, and legislative changes are reviewed and updated regularly to reflect current UK tax years.
Content and calculators are reviewed and updated throughout the year, with particular attention given to:
This page was last updated in October 2026.
This site provides general information only and is not professional tax, legal, or financial advice. The calculators provide estimates based on standard tax rules — your individual circumstances may differ.
Always consult a qualified accountant or tax adviser for advice specific to your situation. This is especially important for:
For questions, corrections, or feedback:
Email: hello@ir35guide.co.uk
This site is not affiliated with HMRC, any accountancy firm, or government body. It is an independent resource for UK contractors.