Test how fast your reflexes are with this simple reaction time game. Click to begin, then wait: the box will turn green after a random delay, and the moment it does you click as quickly as you can. Your reaction time is shown in milliseconds, and the tool keeps your best result across attempts so you can try to beat your own record. Most people react to a visual cue in roughly 200 to 300 milliseconds, so anything under that is genuinely quick. Watch out for clicking too early, which counts as a false start and asks you to try again. It is a fun way to warm up, compare with friends, or just see how sharp you are feeling. Everything runs locally in your browser.