Latency, not frequency
Reaction Time Test
Wait for green, then click as fast as humanly possible. Five rounds, millisecond precision, and an honest look at how twitchy you really are.
Click when the screen turns green
The screen will turn red, then — after a random 1.5–5 second delay — green. Click (or tap, or press space) the instant it does. Five rounds, then your results. Click anywhere to begin.
This test involves sudden color changes between red and green. If you are sensitive to visual flashes or have photosensitive epilepsy, please skip this test.
What your reaction time means
Simple visual reaction time — see a change, respond — averages around 250–280 milliseconds for adults. That number is the sum of a whole pipeline: light hits your retina, the signal travels to the visual cortex, your brain decides, the motor command travels down your arm, and your finger physically moves the button. Each stage costs tens of milliseconds, which is why even elite reflexes bottom out around 150 ms rather than zero.
What moves the number: sleep is the big one — a bad night can add 30–50 ms. Age matters gradually: reflexes peak in the late teens and twenties and slow a few milliseconds per decade after. Caffeine buys a small, real improvement; alcohol costs a large one. And your equipment is invisibly included in every score: a 60 Hz monitor and a wireless mouse can add 20+ ms of latency that has nothing to do with your nervous system.
Can you train it? Raw latency, only slightly — practiced testers shave maybe 10–20 ms. What athletes and pro gamers actually train is anticipation: reading cues earlier so the decision is already made when the stimulus arrives, and automating the response so no conscious choice is needed. That's why your consistency (the ± number) usually improves before your average does — and why five rounds tell you far more than one.