Reaction time test
Wait for the panel to turn green, then press any key as fast as you can. The test reports every attempt in milliseconds, keeps your personal best locally, and shows median and spread so you can judge consistency rather than one lucky run.
Wait for the panel to turn green, then respond as fast as you can with any key.
Reaction time includes your nervous system. Most people land between 200 and 300 ms; only the few milliseconds above your measured input latency belong to the machine.
What this reaction time test measures
It measures simple visual reaction time: the gap between the moment the green cue is actually painted on your screen and the moment your key press reaches the page. That includes your own perception and motor response plus a small amount of display and input delay from your hardware.
How to use it
- 01Press Start and keep your hand resting in a normal position.
- 02Do not press early — an early press is flagged and does not count.
- 03React the instant the panel turns green, using any key.
- 04Run at least five attempts so the median becomes meaningful.
- 05Compare runs on the same machine, screen and refresh rate.
How the result is calculated
The cue timestamp is taken after the browser confirms the green frame has been painted, not when the state changes. Your reaction time is the difference between that timestamp and the key event. The summary shows the median, which resists outliers, alongside your fastest attempt and the spread across the session.
What affects your score
Monitor refresh rate and panel response, keyboard polling rate, browser and system load, fatigue, caffeine, sleep, and how much you anticipate the cue. Wireless peripherals and power-saving modes can add a few milliseconds. Because a browser only sees part of the chain, treat this as a consistent relative measure rather than an absolute hardware figure.