Reaction Lab is a free collection of browser-based reflex, aim and memory tests designed to be quick to start and easy to replay. There is no download and no account is required.
Reaction measurements are performed in the browser. Your hardware matters: display refresh rate, mouse or touchscreen latency, operating system, browser and device performance can all influence a result.
Because of that, Reaction Lab is best used for entertainment, self-comparison and practice rather than as a medical, diagnostic or laboratory measurement tool.
The goal is to make reaction testing feel more like a small arcade than a single plain stopwatch. Different modes test different combinations of reflex speed, attention, aim, inhibition and short-term visual memory.
Reaction Lab is currently free to use. The site may use advertising to help cover hosting and development costs. Ads, when introduced, should be kept away from rapid-click gameplay controls to reduce accidental interaction.