Wait for the box to turn green, then click as fast as you can.
Best
-
Median
-
Mean
-
Tip: press Space for faster, more consistent timing than mouse clicks.
How to Use
Click the box to start. It will turn red and wait for a cryptographically random delay between 1.5 and 5 seconds. When it turns green, click as fast as you can. Your time is measured in milliseconds using performance.now().
If you click during the red phase, you jumped the gun: the attempt resets and is not counted. This prevents gaming the test by mashing the mouse.
On desktop, pressing Space is usually 10-30 ms faster than clicking because keyboards have less input latency than mice and trackpads. Your last 10 attempts are kept on your device with best, median, and mean times.
About This Tool
Reaction Time Test measures how fast you can click after a visual signal appears. The stage is red while you wait; after a crypto-random 1.5–5 second delay, it turns green. Click or press space as fast as you can.
Results are measured with performance.now() for millisecond precision. The last ten attempts are kept on your device with best, median, and mean times, plus a histogram of your run.
Random tools are most helpful when the rules are clear before the result is generated. Decide what the input means, whether duplicates are allowed, and whether the first result should be final. Clear rules make the result easier to trust and explain.
For casual choices, games, classroom activities, examples, and creative prompts, a browser-based tool is usually enough. For regulated contests, high-value selections, safety decisions, legal records, or professional advice, use a process designed for that responsibility.
Last reviewed: April 20, 2026
Frequently Asked Questions
Adult averages fall in the 200-300 ms range for simple visual click tests. Under 200 ms is exceptional. 300-400 ms is normal. Over 450 ms suggests device latency or distraction. Athletes tested with specialized equipment sometimes score under 150 ms, but browser tests always include display + hardware latency.
Browser reaction tests measure display latency + browser input latency + OS latency + your reflexes combined. Expect 30-80 ms of non-you latency. Results are most useful as a personal benchmark over multiple runs, not an absolute physiological measure.
Yes. Keyboards register keypresses 10-30 ms faster than mouse clicks on most systems. Pressing Space is the usual way to maximize your best time.
Your best time and last 10 attempts are saved in your browser's localStorage. Nothing is sent to a server. Clearing browser storage or using "Reset stats" deletes the history.
The delay between red and green uses crypto.getRandomValues to pick a uniform value between 1500 ms and 5000 ms. You cannot anticipate it reliably.
Sub-second reflex timing depends on attention, posture, hand position, recent caffeine, and device load. 20-50 ms variation between attempts is normal. Run 5-10 attempts and use the median for a stable personal number.
Related Tools
Random numbers in any range. Clean and instant.
Guess the country from its flag. Four choices, regional filtering, streaks saved.
Play Rock Paper Scissors against a crypto-random bot. Endless, best-of-5, best-of-10.
Add your choices and spin. Let chance decide.