What Is a Reaction Time Test?
A reaction time test measures the delay between a stimulus, such as a screen turning green, and your physical response, such as a click. That delay includes the time your eyes and brain take to detect the change, the time your nervous system takes to send a command to your hand, and the time your device takes to register the input. For most young adults the visual average is around 250 milliseconds, roughly a quarter of a second.
Gamers use these tests to compare setups and track progress, athletes use them to train anticipation, and many people simply enjoy the challenge. ReflexLab measures time with the browser's high-resolution performance.now() clock and reads input on pointerdown, so your result is not inflated by click-release delay. Every score you set is stored only on your own device.