How to use the reaction time test
- Click, tap or press Space on the blue box that says Click to start.
- The box turns red and says Wait for green… Keep your finger ready, but don't move yet. The wait is random, between 1.5 and 5 seconds, so you can't predict it.
- As soon as the box turns green and says Click!, click, tap or press Space. Your reaction time appears in milliseconds (ms).
- If you react before the green appears, you see Too soon! That try is not scored; just click to try it again.
- After five scored tries you get your Average and Best try. Each round is added to Your rounds, and your lowest average is kept as your Best average.
How the test measures your reaction time
A reaction time test is only as good as its clock. This one uses the browser's high-resolution timer (performance.now()) and the timestamp the browser attaches to your click, tap or key press (event.timeStamp), rather than the moment the page's script gets round to handling it.
The start of the measurement matters just as much. Changing the colour of the box does not make it appear on screen immediately: the browser has to draw a new frame, and the screen shows it at its next refresh. So the test switches the box to green inside a requestAnimationFrame callback and starts the clock at the next frame, once the green frame has been handed to the display, instead of at the moment the colour was requested. The box also has no fade or animation, which would make the green appear gradually. A fresh random delay and rejected early presses mean guessing does not pay off.
What affects your result
The number you see is your own reaction plus some delay from your equipment, which no website can fully remove:
- Display refresh rate. A 60 Hz screen draws a new image about every 16.7 ms, a 144 Hz screen about every 6.9 ms. The test shows the refresh rate it detects under the results. Faster screens tend to shave a few milliseconds off.
- Display and input lag. TVs, some monitors and wireless or Bluetooth mice and keyboards add their own processing delay. Game mode on a TV and a wired mouse usually help.
- Device load. Battery saver or many open tabs can delay frames and input events.
- Touch screens. Phones add touch processing time, so phone and desktop scores are not directly comparable.
- You. Tiredness, attention, caffeine, warming up and age all change reaction times. That is why the test averages five tries.
What is a good reaction time?
Results vary a lot with the device, so treat these as rough guides rather than norms. On a typical screen with a mouse, many people land somewhere around 200 to 300 ms. Averages consistently below about 200 ms are fast, and results that get closer to 150 ms are uncommon. Anything under about 100 ms is almost always a lucky guess rather than a real reaction. Compare yourself mainly with your own earlier rounds on the same device.
| Average | Rough meaning on a typical setup |
|---|---|
| Under 200 ms | Fast |
| 200–300 ms | Typical |
| Over 300 ms | Slower than typical, or a laggy device or touch screen |
Visual vs auditory reaction time
This is a visual simple reaction test: one signal, one response. Reactions to a sound are generally reported to be somewhat faster than reactions to a light, because hearing reaches the brain by a shorter processing path. Choice reaction tasks, where you must pick the right response among several, take longer than simple ones. Real-world tasks such as braking in a car add decisions and movement, so they take much longer than a score here.
How to improve your reaction time
- Use a wired mouse or keyboard and a high refresh rate screen if you have one, and close heavy apps.
- Rest your finger on the button and keep your eyes on the centre of the box.
- Warm up with a round first, and stay rested: sleep and breaks matter more than most tricks. Gains from practice are usually modest.
- For clicking speed rather than reaction speed, try the CPS test.
Troubleshooting
- Every try says Too soon: you are clicking during the red phase. Wait until the text changes to Click!.
- Results seem slow or jumpy: check your mouse buttons with the mouse test, close other tabs and turn off power saving. On a phone, tap with a fingertip rather than a nail.
- Space does nothing: click the box once so the page has focus, then use Space.
- The try was cancelled: switching tabs or apps during a try stops it, because the timing would be meaningless.
- Red and green look alike to me: the text and icon change too. Red says Wait for green…, green says Click!.
Privacy: the test runs entirely in your browser and sends nothing to a server. Your best average and last 20 rounds are kept only in this browser's local storage; use Clear history to delete them. More checks are on the device tests page, such as the typing speed test. To time something yourself, use the online stopwatch.
Frequently asked questions
What is the average human reaction time?
For a simple visual test like this one, many people score roughly 200 to 300 milliseconds on a typical computer screen. Your result also includes your screen and mouse delay, so the same person can score differently on different devices.
Is 250 ms a good reaction time?
Yes, 250 ms is a normal, healthy result on a typical setup. Averages below about 200 ms are fast. Compare against your own earlier rounds on the same device for the fairest picture.
Why is my reaction time slower on my phone?
Touch screens add processing time before the browser receives your tap, and phones may run at a lower refresh rate or in a power saving mode. That can add tens of milliseconds compared with a wired mouse on a desktop monitor.
How accurate is an online reaction time test?
The timing itself uses the browser's high-resolution clock and the exact event timestamp, and the clock starts when the green frame is shown. The remaining error comes from your screen and input device, typically from a few milliseconds up to a few tens, which is why the test averages five tries.
What is the difference between reaction time and reflexes?
A reflex, like pulling your hand away from something hot, is an automatic response that does not need a decision. Reaction time measures a voluntary response to a signal, which goes through the brain, so it is slower than a reflex.
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