Reaction Time Test
React to five random visual signals, then see an average, median, spread and laboratory-reference percentile without an account.
- Fewer clicks, keyboard friendly
- Features others lock behind paywalls
Reaction time test
Start a round, wait for the signal, then press the panel as soon as it changes.
Ready for round 1. Start when you are ready.
Keyboard controls
The percentile is a laboratory-reference estimate, not a diagnosis or a browser ranking. Results under 100 ms are treated as early responses and are not counted.
Your rounds and best average stay in this browser; nothing is sent to a server.
How to use
- Click, tap, or focus the large panel with Tab and press Space or Enter to start round 1.
- Wait through the randomly timed warning state; pressing before the signal does not count.
- Press the panel as soon as it says “Press now!” to record a result in milliseconds.
- Repeat until all five rounds are recorded, using the same device and input method for comparable results.
- Read the average, median, spread and lab-reference percentile; a lower millisecond value is faster.
What the five-round result means
This is a simple visual reaction-time task: wait for a visual signal, then make one response. Each round waits a random 1.5–4.0 seconds so a fixed rhythm cannot predict the cue. The average is the sum of accepted rounds divided by their count. The median is the middle result after sorting, so one unusually slow or fast round affects it less. Spread is slowest minus fastest; a smaller spread means the five attempts were more consistent. Responses below 100 ms are not counted because they are likely anticipatory presses, not responses to a displayed signal.
How the reference percentile is calculated
The displayed percentile is context, not a ranking of site visitors. It estimates the share of a laboratory reference distribution that was slower than your five-round average, using a normal-distribution approximation based on Woods et al. (2015), Experiment 1: 1,469 adults aged 18–65 had a measured simple visual reaction-time mean of 231 ms and standard deviation of 27 ms. That study used calibrated equipment and 120 measured trials per person, while this browser test uses five rounds and includes your screen, browser and input-device latency. Do not use the percentage as a medical, fitness, driving or cognitive assessment.
Make comparisons fair
A browser result includes more than a person’s response: display refresh and response time, operating-system scheduling, browser timing, mouse or touch latency, and the chosen input all contribute. Woods et al. measured and corrected hardware delay in their laboratory setup; that correction cannot be transferred to an unknown browser and device. For a useful personal trend, use the same display, browser, power mode and mouse, keyboard or touchscreen input. Compare complete five-round averages rather than selecting a single fastest attempt.
Frequently asked questions
What is a reaction time test?
A simple visual reaction time test measures the delay between a visual cue and one intentional response. This test randomizes a 1.5–4.0-second wait, records five accepted responses in milliseconds, and reports lower values as faster.
What is a good reaction time in milliseconds?
A 2015 laboratory study of 1,469 adults aged 18–65 measured a 231 ms mean simple visual reaction time before its study-specific hardware correction. A browser result is not directly comparable because your display, browser and input device add their own delay, so use the number mainly to compare your own five-round sessions on the same setup.
How is the reaction-time percentile calculated?
The lab-reference percentile estimates how much of the Woods et al. 2015 laboratory distribution was slower than your five-round average, using its 231 ms mean and 27 ms standard deviation. It is a statistical reference, not a percentile of website users and not a clinical norm.
Why did my reaction-time round not count?
A press before the signal is a false start and is not recorded. A measured response under 100 ms is also excluded because it is likely an anticipated press rather than a response to the visible cue.
Can I take the reaction time test on a phone or keyboard?
Yes. Tap the large panel on a touchscreen, or focus it with Tab and use Space or Enter. Keep the same input method when comparing results because touch, mouse and keyboard latency can differ.
Are reaction-time results private?
Yes. The current five-round session and the best completed average are processed and stored in the browser you use. The tool does not require an account or send results to a server.
Related tools
Updated 2026-10-28