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 Lab saves your reaction-test history locally in your browser, builds a personal stats dashboard, tracks daily and weekly play streaks, unlocks achievements and calculates a game-style Reaction Lab Score.
Completed results are also archived privately so website deployments do not erase the site's historical reaction-test dataset. Public visitors cannot browse that archive.
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 free to use. The site includes Google AdSense integration and may display advertising once Google approves ad serving. Ad placements are designed to remain clearly separated from rapid-click gameplay controls to reduce accidental interaction.
Reaction Lab is built around small, browser-based experiments that give immediate feedback without requiring an account. The games use browser timing APIs and local storage for personal results. Where a page discusses scientific evidence, the guide links to the research source used for the claim.
The site separates simple reaction, choice reaction, aim movement, memory, auditory response and attention tasks because they do not measure exactly the same thing. Results are described as browser-based estimates and training scores, not clinical measurements.
Guides are written to answer a specific question, explain practical limitations and point readers to related tests or primary research. Overlapping topics are consolidated rather than published as many near-duplicate pages. Hardware and browser latency are called out whenever they materially affect interpretation.