Reaction Time Test
A reaction time test measures the gap between a signal appearing and your click, in milliseconds. Press the panel, wait between 1.5 and 5.5 seconds, then click the moment it turns green; the timer starts at the change and stops on your click. Clicking during the wait shows "Too early" and no score. A 2015 study of 1,469 adults put the mean simple reaction time at 231 ms.
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About Reaction Time Test
The panel runs a single loop. You click once to arm it, it waits a random 1.5 to 5.5 seconds, and the moment the state changes the clock starts. Your next click stops it and the elapsed time is pushed into the session list. Because the delay is random you cannot learn a rhythm, and because a click during the wait is rejected with "Too early", guessing costs you the attempt rather than earning a fake score.
Three modes change what you are waiting for. Classic is a colour change to green - a simple visual reaction. Audio plays an 800 Hz tone for 0.15 seconds through the Web Audio API and nothing on screen changes, so it measures auditory reaction instead. Color names one target colour before the round starts and shows a decoy in a different hue first; you must not click until the named colour appears, which turns a simple reaction into a choice reaction and reliably adds time.
Four figures sit under the panel. Attempts counts the rounds in this session, Best is the lowest of them, Average is their mean rounded to a whole millisecond, and Record is the lowest score this browser has ever stored, kept under the key reaction-best. The strip below shows your last attempts so a single lucky round does not flatter the picture. Reset clears the session list but leaves the record alone. Each result also gets a label: under 150 ms Incredible, 150-199 Excellent, 200-249 Great, 250-299 Good, 300-399 Average and 400 or more Keep practicing.
What this cannot do is separate you from your equipment. The measured number includes the time your mouse or touchscreen takes to report the click and the time your monitor takes to draw the new colour, so scores are comparable between your own sessions on the same hardware, not between people on different machines. It is a game and a training aid, not a medical or fitness-to-drive assessment.
Use Cases
How to use
Pick a mode in the row above the panel: Classic waits for green, Audio waits for a tone, Color waits for one named colour among decoys.
Click the panel once to arm the round; it turns to the waiting state and holds for a random 1.5 to 5.5 seconds.
Click - or press the space bar - the instant the signal arrives; the elapsed milliseconds and a rating appear on the panel.
Repeat at least ten times and read Average rather than Best, and watch the strip of recent attempts for consistency.
Check Record for the lowest score this browser has ever held, which survives reloads.
Press Reset to clear Attempts, Best and Average for a fresh session; the Record is deliberately left untouched.
Pro Tips
- Judge yourself on Average, not Best. Best is one lucky round; Average is the mean of every attempt in this session and is the number that actually moves when you improve.
- Anything under about 100 ms means you clicked before you saw anything and got lucky with the timing. The panel cannot tell those apart from a real reaction, so discard them yourself by pressing Reset.
- Color mode is not Classic with extra steps. It names the target colour first and shows a decoy in a different hue, so you have to identify before you act - expect it to be slower than Classic every time.
- Record survives a page reload because it lives in this browser under the key reaction-best, but Reset only clears the session list. Clearing site data is what wipes the record.
- A wireless mouse and a slow display both add milliseconds you did not spend reacting. Compare scores only against your own on the same machine, and use the space bar rather than a click if your mouse feels laggy.
Troubleshooting
The panel shows "Too early" and no time is recorded.
You clicked during the random wait, before the signal. The round is discarded on purpose so anticipation cannot produce a score. Click once more to arm a new round and wait for the actual change - the delay is redrawn every time, between 1.5 and 5.5 seconds, so there is no rhythm to learn.
Audio mode plays no sound.
The tone is generated with the Web Audio API, which browsers keep suspended until the page has received a real user gesture, and which is silenced entirely by a muted tab or muted system output. Click the panel once first, unmute the tab, then arm the round. If nothing comes through, use Classic mode instead - it needs no audio.
Every score is far slower than expected.
Check the mode first: Color mode names a target and shows a decoy, so a choice reaction is being measured and 60-100 ms more than Classic is normal. If you are in Classic, the extra time is usually hardware - a wireless mouse, a high-latency display or a heavily loaded machine. Compare only against your own runs on the same setup.
Record shows a number nobody in this session achieved.
Record is the lowest result this browser has ever stored, under the key reaction-best, and it outlives both the session and a page reload. Reset clears Attempts, Best and Average but deliberately leaves Record alone. Clearing the site data for this domain in your browser settings is what resets it.
The space bar does nothing.
The key handler is attached to the panel, so the panel must have keyboard focus. Click it once first, or tab to it, and the space bar then arms and stops the round exactly like a click. If the page has scrolled so the panel is off screen, the space bar scrolls the page instead.
Frequently Asked Questions
On this test, 200-249 ms is labelled Great and 150-199 ms Excellent. For context, a 2015 study in Frontiers in Human Neuroscience measured a mean simple reaction time of 231 ms across 1,469 adults aged 18 to 65, so a consistent Average in the low 200s already puts you at or ahead of that group average. Anything below 150 ms is exceptional on a browser test.
The largest figure worth quoting comes from Woods and colleagues in Frontiers in Human Neuroscience, 2015: a mean simple reaction time of 231 ms in 1,469 people aged 18 to 65, or 213 ms once their hardware delay was subtracted. The same study found reaction time rising by 0.55 ms for each year of age. Browser tests read a little slower because they include mouse and display latency.
The clock is started with the browser high-resolution timer at the instant the panel changes state, and stopped at your click, and the difference is rounded to a whole millisecond. Nothing is measured during the random 1.5 to 5.5 second wait, and a click in that window ends the round with "Too early" rather than recording a number.
Three, and this page has one of each. A simple reaction test has one signal and one response - that is Classic. A choice reaction test makes you respond only to the right signal, which is Color mode with its named target and decoy. A discrimination test changes the sense used, and Audio mode does that by giving you a tone with no visual change at all.
Most of the improvement people see is in preparation rather than in nerve speed: resting your finger on the button, looking at the centre of the panel instead of scanning it, and not blinking on a long wait. Beyond that, run ten rounds and record the Average rather than chasing one fast attempt, because the mean is what shows a genuine change over days.
They are precise but not absolute. The timer itself is accurate to well under a millisecond, but the number it reports also contains your input device latency and your display latency, which together can be 20-50 ms and differ from machine to machine. That makes results reliable for comparing your own sessions on the same hardware, and unreliable for comparing scores between people.
Because they clicked before they perceived anything and the random wait happened to end just then. The panel cannot distinguish a lucky guess from a genuine reaction, so scores that low are anticipation, not speed. This test keeps no leaderboard for exactly that reason: without controlled hardware and a way to detect anticipation, a headline number cannot be verified.
Only as a rough, informal indicator. Driving involves braking with your foot, peripheral vision, and decisions taken while doing something else, none of which a single click in a browser measures. Formal fitness-to-drive assessment uses calibrated equipment and trained assessors. Treat a slow Average here as a prompt to rest, not as a verdict.
Reaction time is the interval between the signal and the start of your movement. Response time is that plus the time your movement takes to complete. This page measures the pair together, because it can only see the click that ends the movement - which is one more reason to compare your own runs rather than absolute figures from a laboratory.
No. Audio mode replaces the visual signal with an 800 Hz tone lasting 0.15 seconds, so it measures auditory rather than visual reaction. The two are not usually equal: a 2010 study by Shelton and Kumar of 14 subjects reported a mean visual reaction of 331 ms against 284 ms for auditory. The sample was small, but the direction matches most published work.