Reaction time test
Measure the elapsed time between the green signal and the next click or Space press.
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How to use it
Click to start, wait for the panel to turn green, then click as fast as you can. Repeat several tries to compare your own results.
Good to know
Display, input, and browser delays affect the result. This is not a calibrated measurement of biological reaction time.
Run several clean attempts
Click the pad or press Space, wait for it to turn green, then respond once. The green signal appears after a randomly selected delay from 1.5 to almost 4.5 seconds. Clicking during the wait produces “Too soon” and does not add a result. The page retains the last result, best result, and average of the most recent five valid tries.
For a simple comparison, use the same display, browser, and input device and ignore trials where you anticipated the signal.
What the milliseconds include
The number measures browser timing from the signal being set to the next received input event. Display refresh, pointer or keyboard latency, browser scheduling, and background activity are part of it. It is not a medical assessment or a calibrated measure of human reaction time.
Frequently asked questions
What is a good reaction time?
There is no benchmark population for this tool. Compare your own attempts on the same setup; different devices and test designs are not directly comparable.
Why was my click "too soon"?
You clicked before the panel turned green. The wait is random so it cannot be predicted.
Can I use the keyboard?
Yes. Press the spacebar instead of clicking.