Click the moment the screen turns green and measure your reaction time in milliseconds, then challenge a friend
How to use
Click, tap or press Space inside the blue box to start.
The box turns red. Wait, without clicking, until it turns green.
The moment it turns green, click as fast as you can. Your time appears in milliseconds.
Do it five times. Your average is your score, and you can send it to a friend as a challenge.
Why use this tool
Timed from the frame green appears: The clock starts on the exact animation frame the colour is painted and stops on the moment you press, not when you let go, so the result is not padded by the browser.
Guesses do not count: Clicking before green, or under 100 ms after it, is flagged as a guess. Nobody can react that fast, so it will not flatter your score.
Five tries, averaged: One lucky click proves little. See your average, median, best and slowest reaction for a fair picture.
Your screen's delay shown: The test measures your display's refresh rate and tells you how much delay it can add, so a 60 Hz laptop and a 144 Hz monitor can be compared honestly.
Challenge friends: Share a link with your score. Your friend sees what to beat and gets told who won when they finish.
Frequently asked questions
What is a good reaction time?
For a simple test like this, most people average between about 250 and 330 ms. Under 240 ms is very fast, and under 200 ms is exceptional. Online results also include a little delay from the screen, mouse and computer.
Why is my reaction time slower on some devices?
Screens only show a new picture every few milliseconds: about 17 ms at 60 Hz and 7 ms at 144 Hz. Wireless mice, touch screens and busy computers add a little more. Compare scores on the same device.
Can I improve my reaction time?
A little. Sleep, caffeine, warming up and focus all help, and practice makes the task familiar. Tiredness, alcohol and distraction make it slower. The biggest gains usually come from not being tired.
Why did it say my click was a guess?
A real reaction takes at least about 100 ms: the eye has to see the change and the brain has to send the signal to your finger. A faster click must have started before green appeared.
Does it work on a phone?
Yes. Tap anywhere in the box. The timer uses the moment your finger touches the screen.