Reaction Time Test
Click the instant the signal appears to measure reaction time.
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What is this?
A reaction time test that measures, in milliseconds (ms), how quickly you click after a visual signal (a green screen) appears. Handy for a quick check of gaming, sports, or driving reflexes.
How to measure · tips
Click the gray stage — it turns red (wait), then after a short delay turns green (go). Click the instant it turns green to record your time. Clicking before green counts as a false start and is not recorded. Try several rounds and compare your average and best. You can also use Space or Enter to click.
Privacy
Your records are stored only in this browser (localStorage) and never sent to a server. Your best record persists only on this device/browser and resets if you clear site storage.
Human average reaction time — a qualitative visual-stimulus benchmark
Human reaction time to a visual stimulus is often reported in psychology and human-factors research as roughly around 250ms (a qualitative figure that varies by individual and by how it's measured). This tool's rating bands (under 200ms = very fast, 200–269ms = fast, 270–349ms = average, 350–449ms = slow, 450ms+ = slow poke) are set with that general range in mind. That said, such figures tend to reflect an average over many repeated trials in a controlled setting, so it's more meaningful to run several rounds and look at your average and best together than to judge yourself from a single click.
What affects your measurement — the latency this tool can't see
This tool computes the difference between the performance.now() timestamp when the stage turns green and the timestamp when your click event fires. That calculation itself is precise, but there's a gap between the moment JavaScript changes the color and the moment it actually becomes visible to your eyes — driven by your monitor's refresh rate (a 60Hz display adds up to about 16.7ms of frame delay; 144Hz adds about 6.9ms) and the display's own response time. The polling rate of your input device — mouse, trackpad, or touchscreen — and OS-level input handling can also delay when your click actually reaches the browser. In short, this tool measures the time from "JavaScript recognized the color change" to "the click event reached the browser," and some amount of hardware-side latency outside that window is always added on top — worth keeping in mind when treating the number as a reference rather than an absolute.