Technology readiness levels (TRL 1–9) explained, with MRL
Technology readiness levels (TRLs) rate how mature a technology is on a scale of 1 to 9. NASA created the scale, and it is now used by the EU Horizon programmes, the US Department of Defense and Department of Energy, and many national grant schemes and corporate stage-gate processes.
The nine TRLs
Levels 1–3 are research, 4–6 are development and validation, and 7–9 are demonstration and deployment.
- 1Basic principles observedScientific research is starting to be translated into applied research. Evidence is usually papers and early observations.
- 2Technology concept formulatedA practical application is proposed. Work is speculative, with analysis but no experimental proof yet.
- 3Experimental proof of conceptAnalytical and laboratory studies validate the critical functions of separate elements of the technology.
- 4Technology validated in labBasic components are integrated and tested together in a laboratory environment.
- 5Technology validated in relevant environmentIntegrated components are tested in a simulated or relevant environment with realistic supporting elements.
- 6Technology demonstrated in relevant environmentA representative prototype or model system is demonstrated in a relevant environment.
- 7System prototype demonstration in operational environmentA near-final prototype is demonstrated in the environment where it will actually be used.
- 8System complete and qualifiedThe final system is proven to work in its final form through test and demonstration.
- 9Actual system proven in operational environmentThe system is proven through successful operation in its real mission or market conditions.
TRL vs MRL
TRL asks whether the technology works. Manufacturing readiness level (MRL), developed by the US Department of Defense, asks whether you can make it repeatably at the rate, cost and quality you need. It runs from 1 to 10.
| MRL | Definition |
|---|---|
| 1 | Basic manufacturing implications identified |
| 2 | Manufacturing concepts identified |
| 3 | Manufacturing proof of concept developed |
| 4 | Capability to produce the technology in a laboratory environment |
| 5 | Capability to produce prototype components in a production-relevant environment |
| 6 | Capability to produce a prototype system or subsystem in a production-relevant environment |
| 7 | Capability to produce systems, subsystems or components in a production-representative environment |
| 8 | Pilot line capability demonstrated |
| 9 | Low-rate production demonstrated |
| 10 | Full-rate production demonstrated |
How to assess a TRL
- Agree which scale wording applies: your funder's, your sector's or your company's.
- Break the system into its critical components.
- For each component, work up from level 1 and stop at the first level you can't evidence.
- Record the evidence for each level met: a test report, dataset or design review.
- Set the system level from the least mature critical component.
- List what's needed for the next level, with an owner and a date.
The free TRL calculator walks you through steps 3 and 4.
Common mistakes
Scoring the best component, not the system
A system is only as ready as its least mature critical component. Score each part, then let the weakest critical one set the system level.
Skipping levels
Lab validation (TRL 4) comes before relevant-environment validation (TRL 5). A level is achieved only when every level below it is also met.
Confusing simulation with a relevant environment
TRL 5 and 6 need a realistic environment: real loads, interfaces and conditions, not only a model of them.
Claims without evidence
Each level should point to a report, dataset or review a third party could check. Reviewers mark down unsupported claims.
Ignoring manufacturing
A technology at TRL 7 can still be at MRL 4. Funders and gate reviews increasingly ask for both.
Track every scale with evidence attached
LaunchRL rolls TRL, MRL, integration, commercial and human readiness up a component tree and turns gaps into owned actions.
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