Reaction time test

How the reaction time test works

Click the box to start. It turns red, waits a random time between one and a half and five seconds, then turns green. Click the moment you see green. The time between the green appearing and your click is your reaction time, in milliseconds. Do it five times and you get your average and your best.

The wait is random on purpose, so you can't count it out. Click while the box is still red and it says too soon: that try doesn't count and simply runs again. You can also press the space bar, or tap on a phone. Only a fresh press counts, so holding a key down does nothing.

The timer starts from the screen frame the green is drawn in, using your browser's precise clock, not from when the page gets around to updating. Nothing is uploaded and nothing is saved.

What's a good reaction time?

On a browser test like this one, most people average somewhere between about 200 and 300 milliseconds, and a typical result is around 250. That number is more than your brain and hand: it also includes the delay of your screen, your mouse or keyboard, and your computer. As a rough guide:

• Under 200 ms: very fast, usually on a quick screen and a wired mouse.
• 200 to 250 ms: faster than most people on a test like this.
• 250 to 300 ms: typical.
• 300 to 400 ms: a little slower than most, often because of tiredness or a slow screen.
• Over 400 ms: worth checking your setup, or trying again when you are fresh.

A single try under about 150 ms is usually a lucky guess rather than a reaction, which is why the average of five matters more than your best. These are rough ranges, not a medical or athletic measure. Reaction time naturally varies with age, sleep, caffeine and how warmed up you are.

Why your setup changes your score

Every part between the green on screen and the click adds a little time. The test can't see these delays, so they end up in your result:

• The screen. A 60 Hz screen draws a new picture about every 17 ms, a 144 Hz one about every 7 ms. TVs in picture modes can add much more; game mode turns most of that processing off.
• The mouse. Most mice report in a few milliseconds or less. A wireless mouse in a power saving mode or with a low battery can be slower. The polling rate test shows how often yours reports.
• The browser and computer. A busy computer, a laptop on battery saver or a remote desktop all add delay.

That is why scores aren't comparable across devices. To track your own progress, use the same screen, mouse and browser each time.

How to get a faster time

• Watch the box, not your hand. Keep your eyes in the middle of it.
• Rest your finger on the button. A light touch, already in place, saves the time it takes to move.
• Don't guess. Clicking on a hunch costs you a try more often than it pays off.
• Warm up. The first try or two are usually slower. Run a couple of rounds before you judge.
• Use a wired mouse and a fast screen if you have them, and close heavy apps in the background.

Gear only moves the number a little; attention moves it more. If you play shooters, the aim trainer works on aiming as well as reacting. Looking at mice? The mouse finder sorts them by weight, shape and connection, and our best gaming mice are a good start.

Questions