Average Reaction Time by Age: What Studies Show

The largest careful measurement of simple visual reaction time in adults comes from Woods et al. (2015), who tested 1,469 adults aged 18 to 65. Two numbers matter from that study:

• 231 ms — the average as actually measured, hardware delays included. This is the closest published equivalent to what a browser test records.
• 213 ms — the same average after removing the delay introduced by the display and input device: the best estimate of the purely human reaction.

For comparison, the long-standing laboratory reference for college-age adults reacting to a light stimulus sits around 190 ms (Jain et al. (2015)) — younger participants, controlled conditions, dedicated equipment. If an online test tells you the "average" is 250 ms or 284 ms without naming a source, treat it as decoration.

Across the adult range, Woods et al. (2015) found that simple reaction time lengthens by roughly 0.55 ms per year of age. Their youngest band (18–24) averaged 217.8 ms; their oldest (59–65) averaged 239.1 ms. Read that again: four decades of aging cost about 21 milliseconds — less than the blink of a frame at 60 Hz, and less than the difference between a good and a bad night of sleep.

The picture across a wider lifespan comes from Der & Deary (2006), who analysed reaction times from over 7,000 UK adults up to their early 80s. Three findings stand out: the slowing is gradual through midlife and steepens in the later decades; responses become more variable with age, not just slower on average; and choice reaction time — deciding which response to make, not just detecting a signal — ages more steeply than simple reaction time.

Two honest caveats. These datasets cover adults: reaction time in children and teenagers is still improving as the nervous system matures, and the studies above simply do not measure them. And every figure is an average of a wide spread — plenty of 60-year-olds outpace plenty of 25-year-olds.

Here is the uncomfortable arithmetic: your screen and input device add 20 to 50 ms to whatever your nervous system does — display latency, refresh rate, browser scheduling, mouse or touchscreen lag. That hardware spread is larger than the entire aging effect from 18 to 65. Comparing your number on a 60 Hz office monitor against someone else's on a 144 Hz gaming setup says more about the monitors than the humans.

State matters too. Sleep, alertness, caffeine and time of day all move your times by meaningful amounts from one session to the next, and reactions to sound are systematically faster than reactions to light (Jain et al. (2015)) — so an auditory test and a visual one are not comparable numbers. The only clean comparison is you against yourself: same test, same device, tracked over time.

You cannot train away the biology of aging, but the levers that remain are not small. Jain et al. (2015) compared physically active and inactive students and found the active group reacted faster to both light and sound — regular physical activity is the best-documented everyday factor. Practice helps too: repeating the same stimulus-response loop makes it more automatic, which is why your fifth attempt on any reaction test is usually sharper than your first.

The rest is unglamorous but real: consistent sleep, an alert (not jittery) state, and testing when you are fresh rather than at the end of a screen-heavy day. None of it turns a 240 ms responder into a 190 ms one — but stacked together, these factors are worth more milliseconds than a decade of aging takes away.

1. Take the reaction time test at least five times and look at your average, not your single best fluke.
2. Compare against the measured adult mean of 231 ms — your browser number includes hardware lag, just like the study's raw figures did.
3. Retest on the same device every few weeks. The trend is the signal; any single session is noise.

The full set of cited reference points — including the age bands — lives on the reaction time test page.