Reaction Time Test

What a reaction time test measures (and what it doesn't)

A reaction time test measures the gap between the moment the screen gives you a signal and the moment you actually press, in milliseconds. Wait for the panel above to turn green, then click or tap as fast as you can. This page runs five attempts and shows your average.

People search for this with a handful of different names, and they don't all mean the same thing:

• Reaction time — see the signal, decide, move. The whole chain, measured end to end. That is what this page records.
• Reflex test — a true reflex fires in the spinal cord before you are consciously aware of it, like pulling your hand off something hot. Strictly speaking, no click-based test measures a reflex.
• Reaction speed test — the same thing as reaction time, just phrased the other way round.
• Dynamic visual acuity — how well your eyes resolve a moving object. That matters in baseball and table tennis, but it is a different ability.

So use whichever name you like, but be clear about what the number is: a simple visual reaction time, with one signal and one response.

How to get an accurate measurement

A browser score is never just your nervous system. It also contains delay added by your hardware. Woods et al. (2015, Frontiers in Human Neuroscience) calibrated their own setup and measured 11.0 ms of display delay plus 6.8 ms of mouse delay — about 17.8 ms baked into every score before the person even enters the picture.

A few things you can control:

• Refresh rate. A 60 Hz monitor redraws only about once every 16.7 ms, so the green cue can sit there unseen for part of that window. At 144 Hz the gap drops to roughly 6.9 ms.
• Touchscreens. A phone takes longer to register a finger and hand it to the browser than a mouse takes to register a click. That is usually why your phone score is worse than your desktop score.
• Browser state. Video in a background tab, a heavy script, or battery-saver mode will all widen your spread.
• Posture. Rest your finger on the button before the round starts, and watch the middle of the panel rather than its edge.

Only compare scores taken on the same device, same browser and same display.

What is a good reaction time

Simple visual reaction times normally land in the 200s of milliseconds. In Woods et al. (2015), 1,469 participants tested with a mouse averaged 217.8 ms in the 18–24 group — and subtracting the 17.8 ms of hardware delay puts the true figure near 200 ms.

So a browser score of 250 ms is not slow. For how this changes with age, why phones read slower, and what actually shortens the number, see average reaction time by age, with pro and animal comparisons, where every figure is sourced.

Reaction time rating scale (our own bands)

The bands below are blockblast.co's own scale, written to make your result readable. They are not an official or certified standard. They are anchored on the Woods et al. (2015) figure of 217.8 ms for 18–24 year olds, measured with hardware delay included, exactly like this page. Other sites use different cut-offs.

The 180–219 ms band is already ahead of the young-adult average quoted above.

Anything under 100 ms means you pressed before the cue rather than because of it. Throw that attempt out.

Pro gamers and F1 drivers

This is one of the most searched angles, and one where most published numbers have no source behind them. We could not find a standardised, published measurement of any individual pro's reaction time, so we do not print one.

Two things can be verified:

• In athletics, World Athletics Technical Rules 16.7 and 16.8 treat a start reaction faster than 0.100 s as a false start. Below that line, the governing body assumes the athlete anticipated the gun rather than reacted to it.
• An F1 race starts when five red lights come on at one-second intervals and then, after a hold of no fixed length, all go out together. The hold has to vary or drivers would learn the rhythm and jump the start. The green cue on this page appears after an unpredictable delay for exactly the same reason.

How humans compare with animals

Animal reaction-time comparisons are popular and mostly unsourced. The measurements that do exist in the literature are largely from insects. Sourakov (2011, Florida Entomologist) recorded a long-legged fly, Condylostylus, reacting to a camera flash in under 5 ms and possibly as little as 2 ms, and set it against earlier published values:

That is one to two orders of magnitude — which is roughly why the fly leaves before the swatter arrives. Cats, dogs and cheetahs get quoted a lot, but we could not trace those figures to a source, so they are not in the table.

Is this the same as Human Benchmark?

The task is the same idea: a simple visual reaction measured from the green cue to your click. But attempt counts, averaging methods and rating bands differ between sites, so the numbers are not directly comparable. This page measures five attempts, shows the mean, and keeps your best score in your own browser rather than on a server.

Other tests worth trying

• If you want to know how fast your finger is rather than how fast you react, the click speed test counts how many clicks you land in one second.
• Accuracy matters as much as speed in most games, so the aim trainer puts thirty targets in front of you and scores both.
• For a day when you'd rather think than twitch, deduce a hidden number in Bulls and Cows.

Pairing this with a different kind of brain test, such as a memory test, shows you more about where your strengths actually sit. One last note: this page is a toy and a self-measurement tool, not a medical test, and nothing here diagnoses a condition.

Reaction Time Test FAQ

What is the average reaction time test result?

Simple visual reaction times usually land in the 200s of milliseconds. In Woods et al. (2015, Frontiers in Human Neuroscience), 1,469 people tested with a mouse averaged 217.8 ms in the 18–24 group, and that figure still includes about 17.8 ms of delay added by the monitor and mouse. This page measures the same way, so your score includes your own hardware delay too.

Is this reaction time test free?

Yes. No download, no sign-up and no extension. Your best result is stored in your own browser and never sent to a server.

Can I take the reaction test on a phone?

Yes, tap the panel instead of clicking. Touchscreens generally need longer to register a finger than a mouse needs to register a click, so the same person often scores slower on a phone. Compare your results across the same device rather than across devices.

Is this the same as the Human Benchmark reaction time test?

The task is the same idea: wait for the panel to turn green, then click as fast as you can, measured in milliseconds. But the number of attempts, the way the average is calculated and the rating bands differ from site to site, so scores are not directly comparable. This page runs five attempts and shows the average.

What is the difference between a reaction test and a reflex test?

People search for both, but they are not quite the same. A reaction is a deliberate response to a signal you perceive; a true reflex happens in the spinal cord before you are aware of it. What this page measures is reaction time — see, decide, click.

Why do my attempts vary so much?

That is normal. Individual attempts swing by tens of milliseconds even for the same person on the same day. Averaging several attempts is far more stable than a single try. Heavy background tabs or battery-saver mode make the spread wider.

Does my monitor's refresh rate affect my score?

Yes. A 60 Hz monitor only redraws about once every 16.7 ms, so the green cue can wait up to that long before it is actually visible. At 144 Hz that gap shrinks to about 6.9 ms. Woods et al. (2015) measured 11.0 ms of display delay and 6.8 ms of mouse delay in their own calibration, so hardware is a real part of every browser-based score.

What is the fastest human reaction time?

There is no certified world record. In track and field, though, World Athletics Technical Rules 16.7 and 16.8 flag any start reaction faster than 0.100 s as a false start, on the basis that a human cannot have reacted to the gun that quickly. Visual tasks like this one are slower than that, so treat sub-100 ms browser scores as a mistimed guess rather than a record.

My best score disappeared.

Best scores live in the browser you played in. Private windows, other browsers and other devices keep their own record, and clearing site data removes it.