Reaction Time Test
Wait for green, then click. Five goes, and your average in milliseconds.
Runs entirely in your browser
Loading the tool…
Click the box or press Space to start. It turns red: wait. When it turns green, click or press Space as fast as you can. Five goes make a score.
- —Average
- —Median
- —Best
- 0 of 5Goes
Click to start and the box turns red. Wait. At some moment between one and a half and four and a half seconds later it turns green, and the time runs from then until you click. Click too soon and the go does not count, because guessing is not reacting.
Five goes make a set, and the page gives the average, median and best. The median is the most honest of the three: one slow go where you blinked moves the average a lot and the median hardly at all.
Most people score between 200 and 300 milliseconds on a test like this. About 150 to 200 of that is you: light reaching the eye, the brain deciding, the signal going to the hand. The rest is equipment. A screen takes time to show the green, a mouse takes time to report the click, and 60 Hz displays only update every 17 milliseconds. A fast gaming monitor and mouse can take 30 or 40 off a score without the person getting any quicker.
So compare scores with your own, on the same machine. Tired, after coffee, first thing in the morning: that is where the numbers mean something.
How to use it
- Click the box or press Space. It turns red.
- Wait for green, then click or press Space as fast as you can.
- After five goes, read your average, median and best.
Questions
What is a good reaction time?
On a browser test like this, most people average 200 to 300 milliseconds, and under 200 is quick. The figure includes the delay of your screen and mouse, so the same person scores differently on different hardware. Compare yourself with yourself.
Why is my score different on another computer?
Because part of every score is equipment. A 60 Hz screen shows a change up to 17 milliseconds late, some monitors add more processing on top, and a wireless or office mouse can add 10 to 20 of its own. A high refresh gaming setup takes most of that away.
Does it matter whether I click or press Space?
A little. The page times the moment the button goes down rather than when it comes back up, for both. Keyboards and mice report at different rates, so pick one and stick to it if you want to compare goes.
Why does it sometimes say too soon when I did wait?
Because the press arrived before the green was on the screen, which counts as a guess. The wait is random, from one and a half to four and a half seconds, precisely so it cannot be learned.
Can I get faster?
Somewhat. Practice helps for the first sessions, as you learn to keep your finger ready and your eyes on the box. Sleep, alertness and caffeine all show up in the numbers. Age slows simple reaction time gradually through adulthood, by a few milliseconds a decade.
Are my results saved?
No. They are held in this tab while it is open and forgotten when it closes. Nothing is stored or sent anywhere.
Your data stays on your device
Everything above runs inside your browser as WebAssembly compiled from Rust. Nothing you type is uploaded, logged or stored on a server. You can load this page once, go offline, and it still works.
This page makes no requests at all, to anywhere. That is not a promise in the copy: it is a Content-Security-Policy header your browser enforces, and connect-src on it is none. Open the network tab and watch nothing happen.