Reaction Time Test

Average reaction time: what the research actually says

"Average reaction time" is not one number — it depends heavily on what kind of reaction is being measured, how old the person is, and whether the measurement was taken in a lab or over someone's home internet connection and mouse. Here is what peer-reviewed sources report, with the ranges kept honest rather than rounded to a single tidy figure.

"Average reaction time" means different things

The single most important distinction in this literature is simple reaction time versus choice reaction time:

  • Simple reaction time — one signal, one response. React to a light turning on, or a screen turning green, with a single button press. This is what this site's reaction time test measures.
  • Choice reaction time — multiple possible signals, each requiring a different response (press the left key for red, the right key for blue). The brain has to identify which signal occurred and select the matching response, and that extra decision step reliably adds time.

Any "average reaction time" figure is only meaningful once you know which of these it refers to. A number for choice reaction time is not directly comparable to a number for simple reaction time, and conflating the two is the most common way these statistics get misquoted.

Typical ranges for simple visual reaction time

A 2021 pilot study of visual simple reaction time in medical students, published in a peer-reviewed journal and archived on PubMed Central, summarised the surrounding literature this way: Earlier studies have reported visual SRTs ranging from 231 ms to 397 ms depending on the equipment and protocol used. That range is wide because studies differ in apparatus, instructions, and how anticipatory or delayed responses are filtered out — not because human reaction time itself varies that much between otherwise similar young adults.

A general figure, held loosely. Within that literature, values clustering in roughly the 200-270 millisecond range for young, healthy adults under controlled laboratory conditions are commonly cited. Treat that as a ballpark, not a precise constant — the exact number in any single study depends on its specific apparatus and criteria, which is exactly why the range above spans from 231 ms to nearly 400 ms.

Reaction time measured through a consumer web browser, on ordinary consumer hardware, tends to land somewhat higher still than laboratory figures, because a browser-based test cannot separate biological reaction time from the screen's own refresh delay and the input device's own latency — see the breakdown on the test page itself.

Reaction time changes with age — but not evenly

One of the largest studies on this question is Der & Deary (2006), which analysed reaction time data from 7,130 adult participants in the United Kingdom Health and Lifestyle Survey. Its central finding is not a single number but a pattern, and the pattern is uneven between the two kinds of reaction time described above:

  • Simple reaction time "shows little slowing until around" age 50.
  • Choice reaction time "slows throughout the adult age range," starting from early adulthood rather than waiting until midlife.

In other words, a 25-year-old and a 45-year-old should expect broadly similar simple reaction times, but the more complex the decision involved, the earlier age-related slowing shows up and the more it accumulates.

Why your own number will vary

  • Alertness and fatigue. A tired or distracted nervous system reacts measurably slower than a rested, focused one, in the same person on different days.
  • Practice with the specific task. The first few attempts at any new reaction test are usually slower simply because the exact rhythm and timing of the test are unfamiliar, independent of underlying reflex speed.
  • The measurement chain. A trackpad, a Bluetooth mouse, a phone touchscreen, and a wired gaming mouse do not add the same amount of latency, and a low refresh-rate display shows the "go" signal later than a high refresh-rate one — see the honest breakdown on the test page.
  • Task type. As above, choice reaction time is reliably slower than simple reaction time in the same person, because it includes an extra decision step simple reaction time does not.

Sources

These figures describe patterns from published research; they are not a personalised or clinical assessment, and no source here is a substitute for a doctor or a qualified researcher's judgement about a specific individual.

Reaction time testRun five attempts and see your own best and mean, measured with a high-resolution browser clock. Click speed (CPS) testA different measurement: how many clicks you can land in a fixed window.