What this site is for
Reaction Lab is an educational collection of reaction tests and measurement guides. Start with a simple visual response, explore sound or a choice, and use the guides to understand what the resulting number means. No account or payment is required for the public tools.
Our measurement method
Visual timing begins around the requested animation frame and ends when the browser receives input. Sound timing begins when the tone is requested. Neither method observes every physical display, audio or input delay. Results are uncorrected browser intervals, not calibrated laboratory measurements.
Early inputs, interruptions and timeouts are recorded separately. Choice accuracy includes wrong answers and timeouts; its speed summary includes correct responses only. The page explains the protocol before you compare results.
How references are used
Every benchmark guide links its sources and names relevant tasks and samples. We distinguish published observations from illustrative calculations. We do not invent visitor counts, population percentiles, professional-player norms or clinical thresholds. Figures marked as examples are not research datasets.
What a result cannot establish
A browser click does not diagnose health, measure intelligence or certify safe driving. A faster result in one task does not guarantee performance in another. If a source and a test use different methods, we keep that difference visible.
Start with a question
Browse the benchmark notebook to choose an appropriate comparison, or take the visual test to record a first session.