ReactionMetric F1 Reaction Test

What is it?

A free browser five-light reaction challenge inspired by the standing-start light sequence. It measures browser-observed response time and keeps browser/device timing limits visible. It is independent and not affiliated with Formula 1.

How to play

Start a five-attempt session, wait for all five red lights to go out, then click, tap, or press Space. Early responses count as false starts; five valid starts produce a median, best and consistency result.