Home/Methodology

A benchmark is only as good as its method.

How they time you is something most reaction-time sites never disclose. We do, the parts we can't control included. Here's exactly how ReactionBench turns a click into a number, and why that number is honest.

Written byTajammal Maqbool

sub-1 ms

Timing resolution

Rounds per score

Data sent to a server

Median

Statistic we report

THE TIMING PIPELINE

From signal to number, step by step

Arm a random delay

Every round holds a random 1.5–5 second delay before the signal, which leaves no rhythm for you to time. Any input inside that window is a false start and voids the round.

Stamp the painted frame

At the instant the panel truly flips to green, synced to the display's refresh, we record a high-precision timestamp from performance.now(), a clock accurate to well under a millisecond.

Catch the input

As soon as your pointerdown or keydown event fires, a second timestamp comes off the same clock. Reaction time is nothing more than the difference between the two.

Repeat, then take the median

Five valid rounds later we sort them and report the middle value as your score, together with your best round and the spread between them.

t_signal = performance.now() // the frame the panel paints green

t_react = performance.now() // pointerdown / keydown fires

reaction = round(t_react − t_signal) // sub-millisecond clock

THE HONEST BIT

What we can't control

Lab-grade is beyond any browser test, and anyone claiming otherwise is selling something. Hardware we cannot see sits between the green flash and your brain, and again between your finger and our code. The offset it adds is roughly fixed — here's where it comes from.

Display latency

The gap between the browser drawing green and your monitor showing it. Higher on TVs and phones, lower on gaming monitors.

5–25 ms

Input device lag

Wired mechanical gear reports sooner than wireless mice and membrane keyboards. Polling rate counts here.

5–20 ms

Browser event delay

That tiny queue between the OS receiving your click and JavaScript hearing about it.

1–10 ms

Total, typical

Roughly fixed on any given setup, which keeps testing yourself over time fair even when the absolute number runs a touch high.

~20–50 ms

JavaScript can neither see nor correct for any of this. Hence online results, here and on every other browser-based reaction test, read roughly 20–50 ms above what the same person would score on dedicated lab hardware. A score here is a fair, repeatable benchmark. It is not a lab reading, and we won't pretend otherwise.

WHY FIVE ROUNDS

We report the median, not your best

A single attempt is mostly luck — one anticipated click can flatter you by 60 ms. That is why every test runs multiple rounds and reports the median: the middle value, which no single fluke can drag around. We show your spread too, since a tight, repeatable score says more than a lucky peak. Any response under 80 ms is anticipation, not reaction — caught, voided, and replayed, never averaged in.

Median vs. mean. A single 700 ms distraction ruins a five-round average. The median just ignores it and reports the middle, which sits far closer to how fast you really are.

PRIVACY & TERMS

Your scores never leave your device

There is no account, no sign-up, and no server storing your results. Every best score lives in your browser's local storage, on your machine and nowhere else. Clear your browser data and it's gone, because we never held a copy. ReactionBench is provided free, as-is, for curiosity and practice; it is not a medical or diagnostic tool.

No account, ever

Nothing to sign up for, nothing to log in to. Open a test and go.

Stored locally

Your best scores rest in this device's browser local storage and nowhere else.

Nothing uploaded

Results never travel to us or to anyone else. No leaderboard server exists.

Yours to delete

Clear your browser data, or your stats page, and every score is gone for good.

Questions

Why is my phone score slower than my laptop?

More latency comes from touchscreens and mobile displays than from a wired mouse on a fast monitor, usually 20–50 ms worth. That overhead is real and unavoidable in a browser, so we keep desktop and mobile as separate leaderboards for you.

Can I trust these numbers against a lab study?

For absolute values, no — a research rig strips out hardware overhead that a browser adds. For following your own progress and ranking against other web-test users on similar gear, yes. We are a benchmark rather than a clinical instrument.

What happens if I press too early?

That round gets flagged as a false start, voided, and re-armed. It never reaches your median, so mashing can't game the score.

SOURCES

Every percentile on ReactionBench, from the grade table to the "faster than N% of people" line beneath your score, is read off published reaction-time research, not ReactionBench's own visitors. We don't yet hold enough of our own data to build a fair distribution, so published literature stays the honest baseline until we do. Below sits the full, deduplicated citation list behind every curve. Where a source has a public link, its title links to it.

01Der, G., & Deary, I. J. (2006). Age and sex differences in reaction time in adulthood: results from the United Kingdom Health and Lifestyle Survey. Psychology and Aging, 21(1), 62-73. Der, G., & Deary, I. J. (2006). Age and sex differences in reaction time in adulthood: results from the United Kingdom Health and Lifestyle Survey. Psychology and Aging, 21(1), 62-73.
02Kosinski, R. J. (2008). A literature review on reaction time. Clemson University. Kosinski, R. J. (2008). A literature review on reaction time. Clemson University.
03Woods, D. L., Wyma, J. M., Yund, E. W., Herron, T. J., & Reed, B. (2015). Factors influencing the latency of simple reaction time. Frontiers in Human Neuroscience, 9, 131. Woods, D. L., Wyma, J. M., Yund, E. W., Herron, T. J., & Reed, B. (2015). Factors influencing the latency of simple reaction time. Frontiers in Human Neuroscience, 9, 131.
04Jain, A., Bansal, R., Kumar, A., & Singh, K. D. (2015). A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students. International Journal of Applied and Basic Medical Research, 5(2), 124-127. Jain, A., Bansal, R., Kumar, A., & Singh, K. D. (2015). A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students. International Journal of Applied and Basic Medical Research, 5(2), 124-127.
05Hick, W. E. (1952). On the rate of gain of information. Quarterly Journal of Experimental Psychology, 4(1), 11-26. Hick, W. E. (1952). On the rate of gain of information. Quarterly Journal of Experimental Psychology, 4(1), 11-26.