Click when the color changes from red to green. The result includes human, display, browser, operating-system, and device delay.
Click when the color changes from red to green. The result includes human, display, browser, system, and device delay.
Click the area below to start the reaction time test
No test completed yet
No record yet
No tests yet
No tests yet
1. Click to Start
Click the gray area to begin
2. Wait for Green
Don't click while it's red!
3. Click Immediately
Click as fast as you can
This exercise measures the elapsed browser time between a visual change and the click event received by the page. It can be used for personal practice and same-setup comparisons, but it is not a driving, medical, sports, or hardware-latency assessment.
This visual exercise may resemble timing actions used in games:
The displayed interval combines several sources of delay:
There is no single good result for everyone. This visual reaction exercise includes human response, display refresh, browser scheduling, operating-system processing, and input-device delay. Compare several attempts on the same setup instead of using a fixed universal ranking.
Repeat a small set under the same conditions, minimize distractions, and avoid anticipating the color change. Practice may make the task more familiar, but this page cannot separate learning effects from human, display, device, operating-system, or browser delay.
Clicking too early usually happens when you try to anticipate the color change. Focus on reacting to the actual visual stimulus rather than trying to predict timing. The random delay prevents pattern recognition.
The page uses the browser clock to measure time between the visual state change and the received click event. It cannot subtract display lag, operating-system delay, browser scheduling, or device latency. Multiple attempts provide a more stable session average, not a hardware-latency measurement.