Reaction Time Test
Wait for the box to turn green, then click or tap as fast as you can. After 5 rounds you get your average reaction time, an estimated percentile and a chart showing where you sit compared with other people.
The percentile is an estimate: it compares your average with a normal distribution (mean 273 ms, standard deviation 50 ms) that approximates typical visual reaction times measured in browsers. Your device, screen and mouse add their own delay.
| Round | Time | vs. your average |
|---|
How to use the Reaction Time Test
- Press Start test (or click the big box). It turns red: wait and do not click.
- When it turns green, click, tap or press Space as fast as you can. The delay is random, so you cannot predict it.
- Clicked too soon? The round is not counted; click again to retry it.
- Click to continue after each round until all 5 are done.
- Read your results: your average, an estimated percentile, the distribution chart and every round's time. Press Start test again to try to beat your best.
Reaction time percentiles
The table shows the estimated share of people slower than a given average, using the same model as the test: a normal distribution with mean 273 ms and standard deviation 50 ms. For example, 250 ms is 0.46 standard deviations faster than the mean, and about 68% of the distribution lies above it.
| Average reaction time | Faster than about | Rating |
|---|---|---|
| 175 ms | 97% of people | Exceptional |
| 200 ms | 93% | Fast |
| 225 ms | 83% | Fast |
| 250 ms | 68% | Typical |
| 273 ms | 50% | Typical (median) |
| 300 ms | 29% | A little slow |
| 325 ms | 15% | A little slow |
| 350 ms | 6% | Slow |
What happens in those 250 milliseconds?
Simple reaction time is a chain: light from the screen reaches the retina, the signal travels along the optic nerve to the visual cortex, the brain recognises the change and sends a command through the motor cortex and spinal cord to the muscles of your finger. Each step takes time, and the total for a simple visual stimulus is usually 200 to 300 ms. Reactions to sound are typically a little faster (around 150 to 200 ms) because auditory signals reach the brain more quickly.
Reaction time is fastest in your twenties and slows gradually with age. Fatigue, alcohol, some medications and divided attention slow it down; practice and alertness speed it up slightly.
Why it matters on the road
At 100 km/h a car covers 27.8 metres every second, so even a 0.25 second reaction means about 7 metres travelled before your foot moves (about 22 feet at 60 mph). Real driving reactions are much slower than a lab click because you first have to notice and interpret the hazard: road designers commonly assume a perception-reaction time of 1.5 to 2.5 seconds, which at 100 km/h is roughly 42 to 69 metres.
Getting an accurate score
- Use a wired mouse or a keyboard; wireless and Bluetooth devices can add latency.
- Close other heavy tabs and apps so the browser can respond instantly.
- A high refresh rate monitor (120 Hz or more) shows the green box sooner than a 60 Hz screen.
- Take several tests and compare averages rather than single rounds.
Frequently asked questions
What is a good reaction time?
For a simple visual test like this one, most people average between about 200 and 300 ms, with a typical value around 250 to 275 ms in browser-based tests. Under 200 ms is excellent, and under 150 ms is very rare for a genuine visual reaction.
How is my percentile calculated?
Your average is compared with a normal distribution with a mean of 273 ms and a standard deviation of 50 ms, which approximates large sets of online reaction time results. The percentile is the estimated share of people who are slower than you. It is an estimate, not a scientific measurement, because the real distribution is slightly skewed and devices differ.
Why does the test say I clicked too soon?
If you click while the box is still red, or less than 100 ms after it turns green, the click is treated as a guess rather than a reaction. Humans cannot reliably see and respond to a visual signal faster than about 100 ms. The round is not counted and you can retry it.
Does my device affect the result?
Yes. Your screen's refresh rate (a 60 Hz display shows a new frame only every 16.7 ms), display processing, mouse or touch-screen latency and browser load all add delay. Results from different devices are therefore not perfectly comparable; a wired mouse and a high refresh rate monitor give the most accurate times.
How can I improve my reaction time?
Get enough sleep, warm up with a few practice rounds, sit comfortably with your finger resting on the button and focus on the centre of the box. Regular practice, aerobic exercise and action video games have been linked to small improvements, while tiredness, alcohol and distraction make reactions slower.
Is reaction time the same as reflexes?
Not exactly. A true reflex, such as the knee-jerk, is handled by the spinal cord and takes only tens of milliseconds. This test measures simple visual reaction time: your eyes see the change, your brain decides and your hand moves, which takes a few hundred milliseconds.