You clicked at 240 milliseconds. Is that good? Here is what the number represents, what a typical range looks like, and the three things quietly inflating your score.
A reaction time test is about as simple as an interactive measurement gets. Something changes on screen at an unpredictable moment; you respond as fast as you can; the gap is your score in milliseconds.
The number is genuinely meaningful, but it measures something narrower than most people assume. Understanding what's inside that number makes the score more interesting — and explains why the same person can post 200ms one day and 280ms the next.
Your score is the sum of several separate delays, only some of which are you:
These are rough bands for browser tests, which run slower than laboratory equipment. A clinical setup can shave 30–50ms off the same person's score purely by removing hardware delay.
A 60Hz screen redraws every 16.7ms. The stimulus can't appear the instant the game decides to show it — it waits for the next frame. On average that adds about 8ms, and up to 17ms in the worst case. A 120Hz or 144Hz display roughly halves that penalty, which is a real part of why competitive players care about high-refresh monitors.
Trackpads are slower than mice, and mice vary. A trackpad tap has to be distinguished from a stray touch, which takes processing time. Expect a laptop trackpad to cost you 20–40ms against a decent wired mouse, and a touchscreen tap to land somewhere in between.
Reaction time is unusually sensitive to state. Sleep debt, alcohol, and time of day all move it measurably. So does simple warm-up — most people's first attempt of a session is noticeably slower than their fourth.
The interval before the stimulus is randomised specifically to defeat prediction. If you commit to a click before the stimulus appears, one of two things happens: you register a false start, or you post an implausibly low number that reflects a guess rather than a reaction.
There's a genuine physiological floor here. Signal transmission from retina to cortex to muscle can't be trained below roughly 100ms for visual stimuli. Any score meaningfully below that is a timing guess, not a reaction — which is why a suspiciously fast reading is worth retaking rather than celebrating.
Somewhat. Most people can shave 20–40ms through practice, and the gains come from three places: better warm-up, better posture and hand position, and learning to hold a relaxed rather than tensed readiness. Tension is the underrated one — a rigid, braced hand is slower than a loose one, which surprises people who assume coiled readiness helps.
What you can't do is train away the transmission delay. Beyond a fairly early plateau, further practice mostly improves consistency rather than peak speed — and consistency is arguably the more useful thing anyway.
The test here measures simple reaction time: one stimulus, one response. There's a second category — choice reaction time — where you must pick the correct response from several, and it runs considerably slower because a decision now sits between perception and action. That gap between the two, more than either number alone, is what researchers usually find interesting.