Reaction Time

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How to Play the Reaction Time Test

The Reaction Time Test measures how quickly you can respond to a visual stimulus. This reflex test is used by athletes, gamers, and researchers to assess cognitive response speed.

Click or tap anywhere to begin the test
Wait for the screen to turn from red to green
Click or tap as fast as you can when you see green
Your response time will be shown in milliseconds

What's a Good Reaction Time?

The average human reaction time is around 200-250 milliseconds. Professional gamers and athletes often score under 180ms. Scores below 150ms are exceptional. Your reaction time can be improved with practice and is affected by factors like sleep, caffeine, and age.

Fun Fact: The fastest recorded human reaction times in laboratory settings are around 100-120ms, approaching the biological limits of neural signal transmission.

How to play

Tap anywhere to arm the test, then wait while the screen sits on red. The instant it flips to green, tap as fast as you can. Your score is the time between the flip and your tap, measured in milliseconds, and lower is better. Tapping on red just restarts the round, so a twitchy finger costs nothing but pride.

Tips

The red phase lasts a random 1.5 to 4.5 seconds. You cannot time it, so react instead of predicting.

Rest your finger lightly on the screen or mouse button. Travel distance quietly adds tens of milliseconds.

Warm up first. Your opening tap of the day is almost never your fastest.

Since an early tap has no penalty, commit hard the moment you sense the change rather than waiting to be sure.

What a reaction time actually is

The number this test gives you is simple reaction time: how long it takes to respond to a single expected signal with a single prepared movement. It is the purest version of the measurement, and it has been studied since the 1860s. Roughly speaking the delay breaks into three parts. Light hits your retina and the signal reaches the visual cortex, that takes tens of milliseconds. Your brain registers the change and issues a command. Then the command travels down your arm and your finger moves. None of those stages can be skipped, which is why nobody records a genuine 50 millisecond time.

Typing a number into a search box is not a reaction time test, and neither is a game where you can predict the signal. This one uses a random delay of 1.5 to 4.5 seconds precisely so that the green cannot be anticipated. Tapping early simply restarts the round, so there is no penalty and no incentive to guess.

Reading your number

Somewhere around 250 milliseconds is a typical result for an adult on a screen, once you include the time the display itself takes to update.

Below 200 is quick and usually comes from people who are warmed up, rested and using a fast input device.

Below 150 on a normal screen is rare and worth being sceptical of, since screen latency alone can be 20 to 50 milliseconds.

Your first attempt of the day is almost never your best. The test rewards a few warm up rounds before you take a score seriously.

Input matters. A mouse button generally beats a touchscreen, and a wired connection beats a wireless one, by amounts you can see in the number.

Common questions

What is a good reaction time?

Around 250 milliseconds is typical for an adult using a screen. Under 200 is quick, and under 150 is rare enough that the screen or input device is usually part of the explanation.

Why is the delay random?

So that you cannot predict the change. The red phase lasts anywhere from 1.5 to 4.5 seconds, which forces a genuine reaction rather than a timed guess.

Is tapping early penalised?

No. A tap on red just restarts the round. There is no score cost, so there is also no reason to hold back once you see green.