Reaction Time Test

Reaction Time Test helps you measure how quickly you respond to a visual cue. Click to start, wait for the box to turn green, then click, press the spacebar, or tap on mobile as fast as you can. The tool uses high-precision browser timing to measure your reaction speed in milliseconds, then shows your grade, percentile, best score, average, median, and recent history. It runs entirely in your browser with no sign-up required, making it a simple and fun way to test focus, compare attempts, and understand how factors like attention, fatigue, monitor refresh rate, mouse polling, and browser performance can affect reaction time.