Technology Readiness Level is a nine-level scale of technological maturity, running from observation of basic principles at level 1 to a system proven in an operational environment at level 9. The individual topic states which level your project has to move the technology from and to.
The TRL scale describes how far a technology has moved from idea to working product. In Horizon Europe it is not a blanket requirement: it applies only where the conditions of a specific topic require it, and a topic may set its own definitions.
The nine levels
TRL 1 – basic principles observed.
TRL 2 – technology concept formulated.
TRL 3 – experimental proof of concept.
TRL 4 – technology validated in a lab.
TRL 5 – technology validated in a relevant environment (industrially relevant for key enabling technologies).
TRL 6 – technology demonstrated in a relevant environment (same caveat).
TRL 7 – system prototype demonstration in an operational environment.
TRL 8 – system complete and qualified.
TRL 9 – actual system proven in an operational environment (competitive manufacturing for key enabling technologies, or in space).
That is the complete official text: the General Annexes present the scale as one-line definitions. Expanded interpretations are consultancy and national contact point material, not a quotation from the document.
How it affects your proposal
TRL relates to the type of action. Research actions typically operate at lower levels and are funded at 100%; innovation actions sit closer to market and are funded at 70%.
The commonest error is claiming a move from, say, TRL 4 to TRL 8 in a topic whose target range is 3–5. Mismatch with the topic's target level is assessed under Excellence and can lead to a finding that the proposal is out of scope – the evaluation form contains an explicit scope question.
Updated 27.07.2026 · Reviewed by: GetGrant editorial team
