Whichever side of IR35 you are on, the file is what settles it.
A contractor needs to know where they stand. An agency carries the tax when a statement says inside. An end client owns the determination and has to show it took reasonable care. Nebula does the status work for all three — and keeps the dated record that answers an enquiry years later.
Choose your role
A verdict is the start of the job, not the end of it
Any tool can return inside or outside. What an enquiry asks, years later, is what you did, when, on what evidence, and whether you can show it. Everything below is shared plumbing underneath the three products above.
Five factors, weighed separately — never one number on its own
Personal service, control, mutuality of obligation, financial risk and being in business on your own account are each scored and each explained, then tied back to how UK tribunals ruled on the same facts.
- Mutuality is asked about explicitly. HMRC’s CEST does not ask — it treats mutuality as settled by the existence of a contract (ESM11036).
- Every factor carries its own confidence, so a strong verdict built on one weak answer cannot hide.
- A case too close to call is told it is close, with a recommendation to take it to a qualified IR35 specialist.
- Factors
- 5, scored separately
- Free check
- 10 questions
- Full assessment
- 43 questions
- Verdict
- Inside / Outside / Borderline
No accuracy percentage is published, here or anywhere else on this site — nobody audits those claims.
Trust you can test, not trust we assert
Registers you can look up
Nebula Finance Ltd, company no. 12362614 and ICO registration ZB175468. Both open the public register.
Honest about the limits
We publish no accuracy percentages — nobody audits those claims. Borderline results say so, and there is no human review step behind the output.
Your answers stay yours
No ad-tech, no cross-site tracking, never sold. Pages that deliver statutory documents set no marketing cookies at all.
Calibrated against — 17 judgments and 128 HMRC manual paragraphs
- HMRC v RALC Consulting Ltd [2024] UKUT 99 (TCC)
- HMRC v Professional Game Match Officials Ltd [2024] UKSC 29
- Gary Lineker & Anor t/a Gary Lineker Media v HMRC [2023] UKFTT 340 (TC)
- Kickabout Productions Ltd v HMRC [2022] EWCA Civ 502
- HMRC v Atholl House Productions Ltd (Kaye Adams) [2022] EWCA Civ 501
- Uber BV and others v Aslam and others [2021] UKSC 5
- Stuart Delivery Ltd v Augustine [2021] EWCA Civ 1514
- Northern Light Solutions Ltd v HMRC [2021] UKUT 134 (TCC)
- Pimlico Plumbers Ltd and another v Smith [2018] UKSC 29
- Christa Ackroyd Media Ltd v HMRC [2018] UKFTT 69 (TC)
- Autoclenz Ltd v Belcher and others [2011] UKSC 41
- Dragonfly Consulting Ltd v HMRC [2008] EWHC 2113 (Ch)
- Cornwall County Council v Prater [2006] EWCA Civ 102
- Express & Echo Publications Ltd v Tanton [1999] ICR 693
- Carmichael and another v National Power plc [1999] 1 WLR 2042
- Hall (HM Inspector of Taxes) v Lorimer [1994] ICR 218 (CA)
- Ready Mixed Concrete (South East) Ltd v Minister of Pensions and National Insurance [1968] 2 QB 497
Nebula is founded and led by an FCCA-qualified accountant, and the engine is grounded in HMRC's Employment Status Manual and the judgments above. That first part is our word for it rather than something you can look up here — unlike everything else on this page. How we earn trust, and how to verify a document we issued.
Decision-support, not regulated financial, tax or legal advice. No IR35 status determination is made on your behalf.