Reaction Test Lite measures your visual reaction time. The pad turns red while you wait, then flips green after a random delay — tap the instant it changes. Five valid rounds are averaged into one honest number with a human-scale rating.
Tapping early is a false start: it never counts, the round simply re-arms, and the random delay means the rhythm cannot be anticipated. Timing starts on touch-down, not release, and uses a monotonic clock, so the number you get is the number you earned. Your best time is saved and new records are called out.
Around 250 ms is a typical adult average on a phone; screens add their own latency, so compare against your own best rather than other devices. This is a game, not a medical assessment.
Reaction Test Lite works offline, has no account and saves only your best time, on your phone.
Test your reaction time over five rounds and beat your personal best.