Reaction Time Test
Measure milliseconds from a randomly delayed visual signal until the user's tap.
How to use
- Press Start test, wait without tapping, and press the stage immediately when it changes to NOW.
Capabilities and scope
The enhanced runner uses Web Crypto to wait about 1.2–3.7 seconds, then measures a performance.now() difference; tapping before the signal is treated as too early.
How it works
delay=1200+(crypto Uint32 mod 2501) ms; signal and tap timestamps use performance.now(), with the difference rounded to milliseconds.
Example
A tap about 243.6 ms after the signal displays roughly 244 ms.
Useful for
- Repeat on the same device to compare simple visual reaction variation
Before you use it
- The web result includes display refresh, input hardware, OS, and browser event latency and is not a clinical neurological measurement.
Frequently asked questions
Does an early tap count as a score?
No. An input during the waiting phase becomes Too early and the test must be restarted.