The average human visual reaction time is about 250 ms. Under 200 ms is excellent, 200–250 ms is above average, and over 300 ms is slower than average. Athletes and gamers often score in the 150–200 ms range.
Why do my results vary? Attention, fatigue, screen refresh rate and input latency all affect timing. Take several attempts and compare your best or average.
Does this store my data? No — everything runs in your browser; only your best score is saved locally.
Can I improve? Sleep, focus and practice help. Some studies show action games improve reaction time.