How the reaction time test works
Click the box to start. It turns red and waits for a random time between 1.5 and 5 seconds, then turns green. Click, tap or press any key the moment you see green. The time between the green box being drawn and your input is your reaction time for that try. After 5 tries you get your average, your best try and a rating.
If you click while the box is still red, the try does not count and you get a "Too soon" message. A response under 100 ms is also thrown out. Seeing a change, deciding to move and pressing a button takes far longer than that, so a sub 100 ms time is a guess that happened to land. Your early clicks are counted so you can see how much you were anticipating.
What your number really measures
No browser test measures your brain alone. The time shown is your reaction plus the delay of every part of the chain between the screen and the input event:
- The display. The green box only appears on the next screen refresh. At 60 Hz that is up to 16.7 ms away, at 144 Hz up to 6.9 ms. The panel then needs a few more milliseconds to change colour. TVs outside game mode can add far more.
- The mouse, keyboard or touch screen. A mouse polling at 125 Hz reports up to 8 ms later than one at 1000 Hz. Wireless and Bluetooth devices, and many touch screens, add a little more.
- The computer. The operating system, the browser and anything else running all add small delays. Browsers also blur their timers slightly for privacy, which is why the timer resolution is shown above.
Together this is typically tens of milliseconds. That is why the same person can score 20 to 40 ms better on a gaming PC than on an old laptop. Compare your scores on the same setup, and treat comparisons with friends on other devices as rough. The refresh rate shown above is estimated from how often the browser draws frames; for a closer look, run the refresh rate test.
How you compare
For simple visual reactions, where you know what is coming and only have to respond to one signal, healthy adults typically land around 200 to 280 ms in lab conditions and in large online samples. Reactions to sound are usually a little quicker. Anything that adds a decision, such as clicking only on green and not on blue, makes everyone slower.
| Average of 5 | Rating |
|---|---|
| under 180 ms | Exceptionally fast, repeat to confirm |
| 180 to 230 ms | Fast |
| 230 to 290 ms | Typical |
| 290 to 350 ms | A little slow |
| over 350 ms | Slow, check your setup and how you feel |
Reaction time tends to be quickest in your late teens and twenties and slows gradually with age. It also changes within a day: lack of sleep, alcohol, some medicines and simple boredom all make it worse. A single slow set says little; a pattern over many days says more.
Tips for a faster, fairer score
- Use the fastest display you have. A 144 Hz or 240 Hz monitor shows the green box sooner than a 60 Hz one. On a TV, turn on game mode.
- Use a wired mouse or keyboard. A gaming mouse at 1000 Hz polling removes a few milliseconds compared with an office mouse. You can check yours with the polling rate test.
- Close heavy apps and tabs. A busy computer delays both drawing and input.
- Rest your finger on the button. Any travel before the press is added to your time.
- Watch the centre of the box and do not anticipate. Early clicks cost more time than they save.
- Warm up with a few tries. The first try of a session is usually the slowest.
Want to test speed of repetition instead of response? Try the CPS test.
Questions
What is a good reaction time?
On an online test like this one, most people average somewhere around 200 to 300 ms, and that number includes the delay of your screen, mouse and computer. Under about 230 ms is fast. Under 180 ms over a full set of 5 is rare and worth repeating to be sure it was not luck.
What is the average human reaction time?
Simple visual reaction time, where you respond to one expected signal, is usually around 200 to 280 ms for healthy adults. It is a little faster for sounds and slower when you have to choose between responses. Age, sleep, caffeine, practice and attention all move it.
Why is my score different on another computer or phone?
Your result includes the delay of the whole setup: the display, the mouse or touch screen, the browser and the operating system. A 60 Hz laptop screen and a wireless mouse can add tens of milliseconds compared with a 240 Hz monitor and a wired mouse. Compare scores on the same device.
Why did it say too soon?
You clicked before the box turned green. The wait is random, between 1.5 and 5 seconds, so guessing does not work. A click under 100 ms after the change is also treated as a guess, because nobody can see, decide and move that fast.
Is it better to click or press a key?
Use whatever you would use in a game, and stay with it so your scores are comparable. Keyboards and mice are both fast. On a phone, tapping the screen works, though touch screens usually add a little more delay than a good wired mouse.
Can I improve my reaction time?
Somewhat. Practice on the same task helps, mostly in the first sessions. Sleep, a short warm up, staying hydrated and not being distracted matter more than any trick. You can also cut setup delay with a higher refresh rate monitor, game mode on a TV and a wired mouse.
Does a 144 Hz or 240 Hz monitor really help?
It removes some delay from the measurement. At 60 Hz a new frame arrives every 16.7 ms, at 144 Hz every 6.9 ms and at 240 Hz every 4.2 ms, so on average you see the green box sooner. It will not change how fast your brain reacts, but it can lower your score by several milliseconds.
Why does the test use 5 tries?
One click is noisy: a single lucky or slow try can be 50 ms off. The average of 5 is much steadier, so it is a fairer number to compare and save. All 5 tries are listed so you can see how consistent you were.
More tests
CPS testClicks per second in 1, 5, 10 or 60 seconds
Mouse testCheck every button, side buttons and the scroll wheel
Keyboard testPress every key, with ISO, AZERTY and QWERTZ layouts
Controller testButtons, sticks, triggers and vibration for any gamepad
Mic testLevel, clipping, noise floor and a playback check
Webcam testResolution, real frame rate and a snapshot