The Technology Readiness Level (TRL) scale is used to assess the technological maturity of an innovation or technology before its operational implementation. This tool is commonly used in the field of research and development (R&D) to provide a common understanding of a technology’s degree of readiness.
TRL is a concept created by NASA
NASA (National Aeronautics and Space Administration) developed the TRL scale in the 1970s. Originally, this tool had 7 levels of maturity and was used to manage the technological risks of NASA programmes. It was not until 1995, however, that a final, global version of the scale was published, comprising 9 different maturity levels altogether.
Technology Maturity levels
The TRL scale is made up of nine levels, numbered from 1 to 9, representing different stages of technological development. Each TRL is associated with specific criteria that describe the characteristics and performance of the technology at that stage of development.
What is the meaning of TRL?
Evaluating a technology’s TRL enables us to understand where it is in its development cycle and to identify the remaining stages required to reach maturity and commercialization.
The scale is used by researchers, engineers, companies and organizations to assess the TRL.
The 9 levels of TRL
Stage: Idea
- TRL 1 – Fundamental research
This is the initial stage of research, where scientific principles are explored and understood. - TRL 2 – Applied research
Scientific principles are applied to develop technological concepts and prototypes. - TRL 3 – Experimental proof of concept
Experiments are carried out to demonstrate the feasibility of the technology and validate the basic principles.
Stage: Prototype
- TRL 4 – Laboratory validation
The technology is tested in the laboratory to assess its performance and functionality. - TRL 5 – Simulated environment validation
The technology is tested in simulated conditions approximating the actual environment it is to be used in.
Stage: Validation
- TRL 6 – Validation in an operational environment
The technology is tested in an operational environment to assess its performance in real-life conditions. This crucial stage calls for the demonstration of an actual system’s prototype. - TRL 7 – Initial operational deployment
The technology is put to limited operational use and evaluated (at prototype scale) under real-life conditions.
Stage: Production
- TRL 8 – Operational use
The technology in its final form is operationalized on a large scale, demonstrating its reliability and effectiveness. - TRL 9 – Market-ready technology
The technology in its final form is fully developed, validated and ready to be marketed and deployed on a large scale.
The TRL scale and public funding
Horizon Europe
In 2014, the TRL scale was incorporated in projects funded by the European Union (EU) as part of the Horizon 2020 framework programme.
The Horizon Europe programme then adopted the TRL scale as an indicator to improve the positioning of projects applied for in the programme. This unified scale enables applicants and evaluators to meet the expectations of the European Commission (EC).
This makes the TRL scale a key tool in the Horizon Europe 2021-2027 framework conditions for participation. To be eligible for funding, projects need to meet the following requirements:
Activity | Funding rate | TRL |
RIA Research & Innovation Actions | 100 % + 25 % | 4 – 6 |
IA Innovation Actions | 70 % + 25 % | 6 – 8 |
CSA Coordination & Support Actions | 100 % + 25 |
A higher TRL in a call text thus clearly indicates that the EC is looking for a more applicative solution within the project, while a lower TRL indicates that a more fundamental research project is expected.
The TRL is also used to indicate the ‘entry point‘, i.e. the maturity level of a given technology, product or process at the start of the project. In this case, the respective TRL serves as the ‘lower limit’.
TRL in innovation grants and subsidies
In the application procedure for subsidies and innovation, funding agencies use the TRL scale to assess the eligibility of different innovative projects.
TRL in Funding of innovation projects

TRL in Funding of investment projects

TRL Scale in Tax Credits Projects
The TRL scale is also used to assess the eligibility of projects for tax credits, such as the Research Tax Credit (CIR) and Innovation Tax Credit (CII).
Projects in the early stages of development are eligible for CIR, while projects further up the TRL scale are eligible for CII.
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