Reaction Time Test

How the test works

1. Click or tap the big box (or press the space bar) to begin.
2. The box turns red. Wait. After a random pause of 1.5 to 5 seconds it turns green.
3. Click the moment you see green. Your time in milliseconds appears right away.
4. Repeat five times. The page shows your average, your best try and where you sit on the scale.

The pause is random on every try, so you cannot learn the rhythm. If you click while the box is still red, you get a "Too soon" message and that try is repeated. Only real reactions count.

What your number means

This is a simple visual reaction test: one signal, one response. For this kind of test, most people score somewhere around 200 to 300 milliseconds. Results under 200 ms are very fast, and a few tries in the 300s are completely normal, especially on the first round. The colored scale under the box is a rough guide, not a medical measure.

The average of five tries tells you more than any single click. One lucky 170 ms try can happen to anyone, and so can one slow try when you blink. Look at your average and at how close your tries are to each other.

What affects reaction time

• Alertness. Sleep, tiredness and time of day all show up in your score. Most people are slower when tired.
• Age. Simple reaction time tends to be fastest in young adults and slows gradually later in life.
• Practice and focus. Scores usually improve over the first few rounds as you settle in. Distractions make them worse.
• Alcohol and some medicines slow reactions. Never use a test like this to decide whether you are fit to drive.
• Your hardware. See the next section.

Your device adds a delay

Every result includes some time that has nothing to do with you. The screen needs time to show the green color: a 60 Hz display only redraws about every 16.7 ms, and many monitors and TVs add processing time on top. The mouse, keyboard or touch screen also needs a few milliseconds to report the click, and wireless or Bluetooth devices can add more. A fast monitor with a wired mouse gives lower numbers than an older laptop or a phone.

That is why scores from different devices are hard to compare. If you want to track yourself over time, use the same device, the same browser and the same input method.

Tips for a better score

• Rest your finger lightly on the button so the click needs as little movement as possible.
• Look at the center of the box and stay relaxed. Tensing up does not make you faster.
• Do not try to predict the change. Early clicks cost you a try and break your focus.
• Close other heavy apps and tabs so the browser can draw the color change on time.
• Play a few rounds. Your second or third average is usually more representative than the first.

Want more? Measure how fast you can click with the CPS test, or train speed and precision together with the aim trainer.