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Reaction

Reaction tests measure the milliseconds between seeing something and acting on it. The tests here separate three of them: how fast you move on a bare signal, how much a decision costs you, and how steady your hand stays when targets keep coming.

3 games·1 playable now

Reaction3 games

ReactionReaction Time TestWait for green, then press. See how quickly you react.PlayAbout 45s
Coming soonReactionAim TrainerThirty targets, one after another, as fast as you can hit them.60s
Coming soonReactionChoice ReactionDifferent shapes, different keys: reaction time with a decision in it.90s

What reaction tests measure

Reaction time is the total interval between a signal appearing and your correct response landing, measured in milliseconds. It bundles three stages -- seeing, deciding, moving -- and no single test can pull them apart on its own.

That is why this category holds a set rather than one test. Simple reaction time asks only that you move when the screen changes. Choice reaction asks you to identify the signal first and pick the matching key. Aim training swaps the single press for continuous pointing. Run the first two and subtract: the difference is what one decision costs you, in milliseconds.

Who tests their reaction time

Three groups, mostly: competitive players who want to know where their hands sit relative to everyone else, people whose driving or work depends on reacting quickly, and people who are simply curious how far they are from the average.

They should not be reading the same number. For players, consistency matters more than the mean -- how many of ten trials drift past 300 ms says more than the average does. For drivers, the relevant figure is not this one at all; it is the full sequence of noticing, deciding and moving a foot, which runs in seconds. See the FAQ below.

How to read your score

Lower is better and the unit is milliseconds, but the number worth watching is the average across trials and how much it swings -- not your single best run. Eight of ten trials steady at 260 ms beats one at 190 ms and nine at 320 ms.

Browser measurements also run tens of milliseconds slower than lab equipment, which is the equipment talking, not you. Bridges et al. measured this across platforms in PeerJ (2020): browser-based tools carry a fixed visual presentation lag of roughly 15-67 ms and an input lag of roughly 8-48 ms. Switching devices switches rulers, so a personal best is only meaningful against your own scores on the same machine.

FAQ

What is a good reaction time
Most adults score between 200 and 300 ms on a desktop visual reaction test, with the middle of the pack around 250 ms. Under 200 ms is genuinely fast. Under 100 ms almost always means you clicked before the signal appeared, which is a false start rather than a score.
How do I test my reaction time accurately
Run five trials in a row on one device with one input method and take the average. Close background downloads and video first, and use a high refresh-rate display if you have one. Changing device changes the ruler, so scores from two machines are not comparable.
Why is my reaction time slower on a phone
Touchscreens add tens of milliseconds: the panel samples your finger at a fixed rate and the display waits for the next frame. Bridges et al. (PeerJ, 2020) measured visual presentation lag of 15-67 ms and input lag of 8-48 ms across browser-based tools, and phones sit at the slower end. Compare phone scores only with phone scores.
Can you improve your reaction time
The number improves, but what improves is mostly your familiarity with the task -- anticipating the interval, resting your finger on the key, not blinking at the wrong moment. Nerve conduction speed itself does not change because you practised, and a test like this could not show it if it did.
What is the difference between simple and choice reaction time
Simple reaction time pairs one signal with one response: see it, press. Choice reaction time makes you identify which signal appeared and pick the matching key, which typically costs another 100-200 ms. Run both and subtract, and you have measured what a single decision is worth.
What is the average driver reaction time
Road design uses 2.5 seconds as the perception-reaction time for stopping sight distance, the AASHTO value; measured 85th-percentile driver times in the research sit around 1.5-1.9 seconds. That is an order of magnitude above a 250 ms lab press because it covers noticing, judging, deciding and moving a foot to the pedal.
Does reaction time slow with age
Yes. Simple reaction time peaks around the early twenties and drifts slower after that, and choice reaction time -- the version with a decision in it -- slows more steeply. Individual differences inside any age band are far larger than the gaps between bands, so an age chart is a weak way to judge your own score.
Why does my reaction time vary so much between trials
Single trials swing with attention, finger position and where the signal falls in the display's refresh cycle; tens of milliseconds of spread is normal. That is why these tests average several trials instead of keeping your best one -- the best run is usually the one where you happened to guess the interval right.

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