Device Bench

Device test · Input

Reaction Time Test

Wait for green, then click, tap or press Space as fast as you can.

Last— Best— Median— Trials0 / 5 Frame interval—

No trials yet.

Your trials

TrialReactionFrame interval

The third column repeats the frame interval measured when the page loaded, the time between two screen refreshes in this browser. It is context for each time, not an error bar.

How this test works

Click or tap the panel to start a trial, or focus it and press and release Space or Enter. The panel waits a random 1.5 to 4.5 seconds before turning green, with a new delay every time, so you cannot learn the timing and get a head start. Pressing during the wait is a false start: no time is added, and you retry the same trial. The timer starts at the requestAnimationFrame timestamp of the frame that turns the panel green and stops at performance.now() when your press is handled. The page listens for pointerdown and keydown, so it times the moment you press. After a result, activate the panel again for the next trial.

A set is five completed trials. Best is your fastest time, mean is the average, and spread is the slowest time minus the fastest. The median is the middle time once the results are sorted, or the average of the two middle times while the count is even. It is the steadier headline figure, because one distracted trial drags a mean a long way and barely moves a median. False starts are left out of the figures and counted in the final summary. Use “Reset the set” to clear the results, or activate the panel after the fifth result to start a fresh set. Results live only in this page's memory: there is no saved history, no account and no upload, and reloading clears the set.

Your time covers the whole chain from screen to page. The display has to draw the green panel and its pixels have to change, your eye and hand respond, and then your mouse or keyboard, the operating system and the browser each pass the press along before the page records it. The frame interval readout is the median gap between requestAnimationFrame timestamps sampled when the page loads: the browser's estimate of one refresh, which leaves the rest of the display and input delay unmeasured. The refresh rate test shows frame timing in more detail. A faster refresh rate, a wired mouse or a quieter system can shift your times, so change one thing at a time when you compare setups.

Frequently asked questions

What is a normal reaction time?
This page does not give one: it has no population data to compare you with, and a browser result also includes your setup's delays. Compare yourself with yourself instead. Run five trials, note the median and the spread, change one thing (a different mouse, a wired connection, a higher refresh rate) and run five more.
Why does my score change so much between trials?
Reaction time varies from trial to trial with attention, practice and anticipation, and browser scheduling and device delays vary too. That is why the page runs five trials and reports the spread as well as your best. The median is the middle time in your set, and the spread is the gap between your fastest and slowest.
Does my monitor affect the result?
Yes. The green panel appears only when the screen next refreshes, and pixel response adds more delay before you see it. The frame interval readout shows how long one refresh takes in this browser, but it does not measure how long your screen takes to show green, so do not subtract it from your time as a correction.
Is a mouse click faster than the spacebar?
It depends on your mouse and keyboard, so test it: run a set of five with each and compare the medians, keeping everything else the same. Both are timed at the moment of the press. The page cannot separate device delay from your own response, so repeat the comparison before you trust a small difference.
Does clicking early help?
No. A press while the panel is waiting is a false start: it adds no result, does not advance the trial count, and shows up in the summary's false-start tally. Click, tap or press Space to retry. The delay is re-randomised between 1.5 and 4.5 seconds on every attempt, so there is no rhythm to learn.

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