Reaction Time Test

A reaction time test that measures in milliseconds (ms) how fast you press when the screen changes colour or a sound plays. Each set has 5 tries and shows the average, the median and the fastest time.

How to use

1. Under "Mode", choose "Colour change", "Sound" or "One of two colours".
2. Tap the large area or press Space to start waiting.
3. When the colour changes and "Now!" appears, press at once. In "One of two colours", press only for a circle and hold back for a square.
4. After 5 tries, "This set of 5" shows the average, the median and a "Reaction time per try" chart, and the set is saved under "Records".

How it works

• The signal comes at a random moment between 2 and 5 seconds. A press before the signal, or less than 0.1 s after it, counts as a guess and the try is repeated.
• The time includes delays from your screen, mouse or keyboard and browser, so it reads longer than your true reaction time and differs between devices.
• This is for fun and practice and is not a medical test. Records are saved in this browser.

Questions and answers

What is an average reaction time in ms?

The tool does not compare you with other people. It shows the average of your set and your "Best average of 5". Device delays are part of every result, so compare only results measured on the same device.

What is the difference between average and median?

The average is the sum of the 5 times divided by 5. The median is the middle (third) time when they are sorted. One very slow try raises the average but barely changes the median.

Why do I keep getting "Too soon"?

You pressed before the change, or within 0.1 s after it, which counts as a guess. The waiting time is different every time, so wait for the signal before you press.