About & Methodology

Reaction Benchmark is nine short browser tests that measure reaction speed, aim, memory, color discrimination and typing speed. Everything runs in your browser. There is no account and no login wall; apart from the anonymous statistics record described below (and, if you choose to join a leaderboard, the nickname and score you submit) nothing you do here is sent to a server.

Who runs this

It is built and maintained by one independent developer. If something is broken, wrong, or unfair, write to ysc9550@gmail.com and it gets fixed or corrected here.

Every figure quoted here was read back against the paper it came from before it went up. Where a source could not be verified, the number does not appear at all. That rule is why eight of the nine tests carry no percentile.

How the percentiles work

Your score is compared against distributions published in peer-reviewed research. It is not compared against other visitors to this site, because a self-selected sample of people who search for reaction time tests is not a population.

The rule is simple: if we can point to a published norm that plausibly matches the task, you get a percentile and a link to the study. If we cannot, you get your score and your own history instead. Inventing a distribution would be easy and would look more impressive. It would also be a lie.

Reaction Time — reference study, no percentile

Compared against Woods, Wyma, Yund, Herron & Reed (2015), Factors influencing the latency of simple reaction time, Frontiers in Human Neuroscience 9:131: 1,469 adults aged 18 to 65, mean simple reaction time 231 ms, between-subject standard deviation 26.8 ms.

That study measured on laboratory apparatus. A browser adds its own delay on top of the underlying reaction, and measurements of online experiment platforms put that delay at roughly 71 to 87 ms (Anwyl-Irvine, Dalmaijer, Hodges & Evershed, 2021, Behavior Research Methods 53(4):1407–1425). A fair comparison would therefore subtract roughly 80 ms from your time, and on the sample side use the authors' own device-corrected mean of 213 ms rather than the raw 231, so both sides sit on the same device-free scale. Comparing a corrected score against an uncorrected mean would quietly flatter everyone. But your own device may add more or less than 80 ms, and that spread is why the site attaches no percentile to reaction time at all. The correction is honest on average but not for any one visitor, so the study and the offset stay documented here as reference instead of being turned into a "top N%" on screen.

Sequence Memory — percentile shown

Compared against the forward Corsi block-tapping span in Facchin et al. (2024), Regression-based normative data for Corsi Span and Supraspan learning and recall among Italian adults, Neurological Sciences 45(12):5707–5718: 340 healthy adults aged 21 to 89, mean span 4.97, standard deviation 1.03, range 2 to 8. The classic task uses nine irregularly placed blocks tapped by an examiner, so a 3×3 grid clicked on a screen is a close relative rather than the same test.

Aim Test, Number Memory, Visual Memory, Chimp Test, Color Match, Typing Speed — no percentile

No published norm matches these as they are played here.

• Aim Test — movement time depends heavily on your pointing device.
• Number Memory — the clinical digit span is read aloud by an examiner rather than shown on a screen and typed back, and the well-matched published samples we could verify covered narrow age bands.
• Visual Memory — the closest published norms come from the Corsi block-tapping task, which is sequential, examiner-administered and uses physical blocks, while this test presents every square at once.
• Chimp Test — the published work studied trained chimpanzees at controlled exposure durations, not self-paced humans in a browser.
• Color Match — the result mostly reflects your display, not your eyes.
• Typing Speed — the task changes with keyboard layout and language, and no published norm matches sentence typing as it is played here.

Each of those pages explains the reasoning in full.

What we do not claim

None of these tests diagnose anything. They are not screening tools for color blindness, attention disorders, dementia or brain injury, and a low score on a web page is not medical information. If you are worried about your vision or your memory, see a clinician rather than a browser tab.

Accessibility

• Eight of the nine tests never use color as the only signal: states are marked with text, icons or numbers as well. Color Match is the exception, because color discrimination is the thing it measures, and that is stated on the page itself.
• Animation respects the operating system's reduced-motion setting.
• Clickable targets are at least 44 pixels, with one documented exception: on narrow phones the largest memory grids cannot give every tile 44 pixels and still fit on screen, so tiles there are sized down to 30 pixels. That still clears the 24-pixel minimum in WCAG 2.2 success criterion 2.5.8, and it is preferable to the alternative we measured, where forcing 44 pixels made neighboring tiles overlap and steal each other's clicks. The aim test's optional hard modes shrink targets to 32 and 24 pixels on purpose, because hitting something small is the challenge being chosen; the default mode keeps the 48-pixel target.

How this is built and checked

The site has no framework and no UI libraries. It is plain modules and plain CSS, uploaded as static files, which is why pages load in well under a second on a phone. That is not minimalism for its own sake: on a test where the measurement is a timestamp difference, every library sitting between your click and the code that records it is a source of delay nobody can see.

Three third-party scripts load here: Google Analytics, Microsoft Clarity, and the Google AdSense loader that sits idle while our application is reviewed. All of them load asynchronously, so none sits in the measurement path. Analytics and Clarity tell us which pages people use and where they get stuck. None of the three receives your scores, which stay in your browser. Clarity also records how the page was used, so the privacy page spells out what that means and how to switch these off.

Correctness is enforced by checks that fail the build rather than by good intentions. The build refuses to publish if a page's meta description runs long, if an internal link points at a page that does not exist, if a distribution in the norms file has no source URL attached, if an English string is hard-coded into a screen that also has to render in Korean, or if a test stage is missing its keyboard-reachable start button. Each of those checks was added after the corresponding mistake actually shipped.

Before anything goes live, all nine tests are played end to end in both languages by an automated harness that clicks through real rounds and reads the result panel, because unit tests happily pass while a result screen fails to render at all. That harness is how we learned that browsers throttle timers in background tabs badly enough to break timing, which is now blocked outright with a notice instead of a bad number.

Your data

Your personal records (bests, streaks, achievements) are stored in your own browser using local storage and disappear if you clear your browser data. Two things are sent out. When a test finishes, an anonymous statistics record (game, mode, score, device class, language, date, plus accuracy on the aim test and voided-click counts on reaction time; nothing that can identify you) goes toward building this site's own percentile baseline. And if you choose to join a leaderboard, the nickname and score you submit are stored there. See the privacy page for the full detail.

Changelog

• 4 August 2026 — F1 Reaction added as a themed variant of the reaction test: five red lights, a random hold, go on lights-out: the real Formula 1 start procedure. Separate records; not counted in the nine-test set.
• 4 August 2026 — Challenge links: send any finished run to a friend as a duel on the identical board: same targets, same order. One attempt per player, spent the moment it starts; win/lose verdicts, a rematch loop, and link previews that carry the challenger's score.
• 4 August 2026 — Leaderboards now accumulate per game instead of clearing daily; season changes will be announced in advance. Difficulty modes and typing languages keep separate boards, and submissions are protected by signed tokens, minimum play times and rate limits.
• 4 August 2026 — The reaction-time percentile was removed from the result screen. The Woods et al. study and the 80 ms browser offset stay documented as reference, because per-device delay makes one honest correction impossible.
• 3 August 2026 — Typing Speed added as the eighth test, with a Korean-standard play screen, key sounds and a pace graph. Every game got its own daily leaderboard, and results gained tier badges.
• 3 August 2026 — Daily challenge, difficulty modes (chimp and aim), one-line result verdicts, social sharing, and the chimp brand mark.
• 2 August 2026 — Chimp Test added after a teardown of the category leader, bringing the site to seven tests, plus three written guides.
• 2 August 2026 — Visual Memory added, bringing the site to six tests. Grid tile sizing moved to one place after narrow screens were found to overlap adjacent tiles.
• 2 August 2026 — First release: five tests, published-norm percentiles for reaction time and sequence memory, local scores and streaks, share cards.