The average adult reacts to a visual signal in roughly 220 to 240 milliseconds under lab conditions, and age moves that number less than most people expect: about half a millisecond per year. Here are the real numbers for every decade, where the decline comes from, and what separates fast people from slow ones.
The average reaction time at every age
The best age-by-age data comes from lab studies that measure large samples on identical equipment. In one of the largest, 1,469 adults took the same simple reaction test, and every age group from 18 to 65 landed inside a 21-millisecond band.1
Source: Woods et al. (2015), Frontiers in Human Neuroscience. Slowing averages roughly 0.5 ms per year of age.
The slide is steady and small, roughly half a millisecond per year.1 A UK survey of 7,130 adults spanning ages 18 to 82 refined the shape: simple reaction time holds close to flat until about 50, and the slowing picks up from there, while tasks that add a decision to the reaction slow across the whole adult range.2 Decisions age earlier than reflexes do.
Two cautions before you compare yourself to these numbers. They come from optimized lab equipment; a browser test reads higher because your screen, mouse, and browser add their own delay, which is why typical online medians sit near 273 ms across all ages.3 And an average is a midpoint, not a floor: healthy people of the same age differ from each other by more than the entire 21 ms age spread.
When reaction time peaks, and when it fades
Children start slow. Reaction speed climbs through childhood and adolescence as the brain’s processing quickens, and a meta-analysis of 72 studies found the gains continuing into young adulthood.4
The peak arrives early. In a study of 3,305 StarCraft II players aged 16 to 44, within-game reaction speed began its decline at age 24.5 The lab data agrees on the direction: 18-to-24 is the fastest cohort, and each later group runs a touch slower.1 From there the fade stays gentle until it steepens past 50.2
Age is not the whole story
The StarCraft study’s second finding matters more than its first. Older players held their ground in real matches by compensating for slower reactions with better use of shortcuts and command keys: less raw speed, more efficiency.5 Experience is a genuine performance asset, and it keeps compounding long after 24.
The age effect is also small next to the state you show up in. Four decades of aging costs about 21 ms.1 One sleepless night impairs you like being over the drink-drive limit, a badly timed coffee bills your next day, and a laggy device adds tens of milliseconds on its own. Your habits move your number further than your birth year does. Our guides on sleep, caffeine, and how to improve reaction time cover the levers, and every one of them works at every age.
What counts as good at your age
ReflexLab’s rank bands grade browser scores across all ages:
Lab average: Woods et al. (2015), young adults on optimized equipment. Online median: large public web datasets, which include device delay.
For an age-adjusted read, use the lab rate: allow roughly 5 ms per decade past your mid-twenties.1 A 45-year-old averaging 260 ms in a browser is performing like a 25-year-old at 250, and both sit ahead of the typical online tester.
The fairest benchmark is your own history. Run a session on the reaction time test, let it log your average, and race your last week rather than an 18-year-old’s median.
Frequently asked questions
What is a good reaction time for my age?
Lab averages move from about 218 ms in the early 20s to 239 ms in the early 60s.1 Browser tests read higher because devices add delay, with online medians near 273 ms across all ages.3 In a browser, an average around 250 ms is strong for any adult, and beating 273 ms beats the typical tester regardless of your decade.
At what age is reaction time fastest?
The late teens and early twenties. The 18 to 24 cohort is the fastest group in large lab samples,1 a study of 3,305 esports players put the start of the decline at age 24,5 and children are still climbing toward adult speed through adolescence.4
Why is my reaction time slower than the averages here?
Check the measurement before the reflexes. Phones and slow monitors add 35 to 140 ms to a score, and a browser number is not comparable to a lab number.3 Sleep, caffeine timing, and focus swing results by more than the whole age effect. And an average is a midpoint, so half of every age group sits below it.
Sources
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.
frontiersin.org
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. pubmed.ncbi.nlm.nih.gov
Nicosia, J., Wang, B., Aschenbrenner, A. J., et al. (2023). To BYOD or not: Are device latencies important for bring-your-own-device (BYOD) smartphone cognitive testing? Behavior Research Methods. link.springer.com
Kail, R. (1991). Developmental change in speed of processing during childhood and adolescence. Psychological Bulletin. pubmed.ncbi.nlm.nih.gov
Thompson, J. J., Blair, M. R., & Henrey, A. J. (2014). Over the hill at 24: persistent age-related cognitive-motor decline in reaction times in an ecologically valid video game task begins in early adulthood. PLOS ONE.
journals.plos.org
Race your own average
Run a session, get your number, and see where you land against your decade. Then beat your last week.
Take the Reaction Time Test