How fast can a human react? On a simple visual test, the fastest genuine reactions dip well under 150 ms — but anything faster than about 100 ms usually means you anticipated the signal rather than reacted to it.
Click, tap, or press Space when the panel turns green.
Genuine simple-visual reactions bottom out around 120–150 ms for most fast responders. We flag impossibly fast results as false starts because reacting in under ~100 ms means you guessed, not reacted.
Warm up first, remove distractions, and use a low-latency wired mouse. Track your best over many sessions rather than a single lucky tap.
Anything under ~100 ms on this test is not a real reaction — it's anticipation, which we filter out.
Warm up, focus, reduce input latency and take many attempts. Your best emerges with practice.
Trained players often score very well on reaction tasks, but it reflects practice, not a guarantee of skill.
ReactionLab is a browser-based reaction performance test. It is not a medical, neurological, or intelligence assessment. Results depend on your hardware, input device, and browser. See our methodology.