Technology Readiness Levels (TRL) Explained Simply
Technology Readiness Levels or TRLs are a way to describe how developed a new technology is. The scale goes from 1 to 9. TRL 1 represents the earliest stage, where a concept or idea is first formulated. TRL 9 indicates that the technology has been proven to work successfully in real-world conditions.
TRLs are used by scientists, engineers, startups, investors and funding bodies like Innovate UK and the EU Horizon Europe programme. They help everyone understand what stage a technology is at and what needs to happen next.
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The TRL Scale at a Glance
TRL | Stage | What it Means |
|---|---|---|
1 | Basic principles observed | You’ve noticed something interesting that could lead to a new idea |
2 | Concept formulated | You’ve come up with an idea and started to think about how it might work |
3 | Experimental proof of concept | You’ve done early tests to show the idea could work |
4 | Technology validated in lab | You’ve built a small version and tested it in a lab setting |
5 | Validated in relevant setting | You’ve tested it in a more realistic environment |
6 | Demonstrated in relevant setting | A working version is tested in conditions similar to the real world |
7 | Prototype in operational use | A prototype is tested in the real world |
8 | System complete and qualified | The final version has passed all tests |
9 | Proven in real environment | It is now working as expected in the real world |
Breaking It Down
TRL 1 to TRL 3 – Early Research and Testing
This is where everything starts. You are in the research phase. You may be in a lab, at a university or working as part of a technical team trying to understand how something works and whether it could become useful technology.
TRL | Stage | What it Means |
|---|---|---|
1 | Basic principles observed | You’ve noticed something interesting that could lead to a new idea |
2 | Concept formulated | You’ve come up with an idea and started to think about how it might work |
3 | Experimental proof of concept | You’ve done early tests to show the idea could work |
TRL 1
- You observe something that might be useful
- This could be a scientific discovery or a new insight
- There’s no design or system yet, just basic understanding
TRL 2
- You start forming an idea for how this discovery could be turned into a real system or product
- There are no experiments yet, but you’re planning the concept
TRL 3
- You carry out small tests to show the idea could work
- These tests may be simple and don’t prove the whole thing works, just that parts of it make sense
This stage is about learning, exploring and building confidence that the idea is worth pursuing
TRL 4 to TRL 6 – Development and Lab Testing
Now you start developing your technology. You move out of theory and begin building real versions of the idea.
TRL | Stage | What it Means |
|---|---|---|
4 | Technology validated in lab | You’ve built a small version and tested it in a lab setting |
5 | Validated in relevant setting | You’ve tested it in a more realistic environment |
6 | Demonstrated in relevant setting | A working version is tested in conditions similar to the real world |
TRL 4
- You test your technology in a lab
- The setup is controlled and ideal
- You’re trying to prove that it works technically
TRL 5
- You move beyond the lab and test in a more realistic setting
- This could be a factory, a hospital or outdoors, depending on the technology
- It’s still controlled, but you’re simulating the real environment
TRL 6
- You build a working version and test it in a relevant environment
- This is not just a lab experiment
You are demonstrating the full system in an environment that closely matches how it will be used
TRL 7 to TRL 9 – Deployment and Real-World Use
At this point you are focused on making sure the technology works reliably in the real world.
TRL | Stage | What it Means |
|---|---|---|
7 | Prototype in operational use | A prototype is tested in the real world |
8 | System complete and qualified | The final version has passed all tests |
9 | Proven in real environment | It is now working as expected in the real world |
TRL 7
- You test a prototype in an operational environment
- This is often called a field trial or pilot
- You are gathering data and feedback from real users in real conditions
TRL 8
- You finalise the system
- It’s now a full product or solution
- All tests have been passed and it’s ready for market or wider rollout
TRL 9
- The technology is being used in real life
- It is operating in its intended setting and delivering results
- You’ve reached the end of the TRL journey
Why TRLs Are Useful
TRLs give everyone a common language. If you are applying for funding from UKRI, Innovate UK, or the European Innovation Council, you will often be asked what TRL your project is at. It helps assess if your idea is ready for support, and what kind of help it needs. Here is how TRLs are often used.
TRLs in UKRI and Horizon Europe Funding
Program | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
EIC Pathfinder |  | | | | |||||
EIC Transition | | | |||||||
UKRI/Innovate UK | | | | | |||||
Innovate UK (Loan) | | | | | |||||
EIC Accelerator | | | | | |
Summary
Technology Readiness Levels (TRLs) provide a clear way to show how developed a new idea or innovation is. They range from the earliest concept through to fully tested products being used in the real world. Whether you're developing software, inventing new materials, or working on clean energy solutions, TRLs help you track progress and communicate where you are in the journey. Understanding your TRL is a valuable first step when seeking funding or preparing to bring your technology to market.
Frequently Asked Questions (FAQs) about TRLs
How do you define TRL?
TRL stands for Technology Readiness Level. It’s a scale from 1 to 9 used to show how developed a technology is — from the first idea (TRL 1) to a finished, working product used in real life (TRL 9).
What is the difference between TRL 5 and TRL 6?
Both TRL 5 and 6 are about testing outside the lab, but they are different in how complete the technology is.
TRL 5 means the technology has been tested in a relevant setting, but parts of it may still be experimental.
TRL 6 means a working version of the full system has been built and tested in a realistic environment.
Think of TRL 5 as early field testing, and TRL 6 as a more advanced demonstration.
What is a TRL in ESA?
The European Space Agency (ESA) also uses the TRL scale. It works in the same way — TRL 1 is early research, and TRL 9 is a fully working space technology. ESA often expects higher TRLs because space systems must be tested thoroughly before launch.
Is there a TRL 0?
No, there is no official TRL 0. Some people use the term informally to talk about very early thinking or research before TRL 1, but it’s not part of the recognised 1 to 9 TRL scale.
What is TRL 5 level?
TRL 5 means the technology has been tested in a setting that mimics how it would be used in the real world. It’s more advanced than a lab test, but not yet a full prototype. It shows that the idea works in realistic conditions.
Is there a marker in TRL?
TRLs don’t have physical checkpoints, but each level comes with clear criteria. To demonstrate your progress, you might need lab results, field trial data, or real-world demonstrations. These proof points—often called evidence requirements—can vary depending on the funder.
Not Sure What Your TRL Is?
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