What studies report
For a simple task, where one signal appears and you make one response, human reaction times are on the order of 200 ms. Figures widely cited in the research on mental chronometry put the mean for college-age adults at about 190 ms to a light and about 160 ms to a sound.
Those are laboratory numbers, taken with equipment built to add as little delay as possible. They describe young adults doing the simplest possible task. They are a reference point, not a pass mark.
Why an online test gives you a higher number
When you take a reaction test in a browser, several delays that have nothing to do with you are added to the result.
- A 60 Hz screen draws a frame every 16.7 ms, so the signal can reach your eyes up to that much late, before the panel’s own processing time is added. At 144 Hz the frame wait is under 7 ms.
- A mouse reports its state at intervals rather than continuously, and a touchscreen is slower still to register a press.
- The browser needs a moment to hand the click to the page.
Together these commonly add tens of milliseconds. Someone who would measure 190 ms in a laboratory may well see 220 or 240 ms on an ordinary computer, and more on a phone. That is the equipment, not the person.
Simple and choice reaction time
Everything above is simple reaction time: one signal, one response. When you have to choose between responses, for example press left for red and right for green, the time is longer, and it grows as the number of choices grows. Most of what happens in a game or behind the wheel is choice reaction, which is why real-world responses take far longer than a test result suggests.
Reaction time and age
Reaction time improves through childhood, peaks in early adulthood and then slows gradually. A large 2014 study of StarCraft 2 players, published in the journal PLOS ONE under the title “Over the Hill at 24”, found that response speed in the game began to decline at around 24 years of age.
The slowing is gradual, and it is small next to the difference between a rested and a tired person, or between a 60 Hz and a 144 Hz screen. This site does not publish a table of averages by age, because the tables that circulate online rarely say where their numbers come from.
What slows you down on the day
- Too little sleep. Slower and less consistent reactions are among the best documented effects of sleep loss.
- Alcohol, even in modest amounts.
- Distraction. Divided attention costs more than most people expect.
- Tension. A rigid hand is slower to move than a relaxed one.
How to improve your reaction time
- Shorten the movement. Part of every result is the time your finger takes to press. Rest it on the button with the slack taken up.
- Practise the task you care about. Gains are specific. Practising a light makes you faster at lights and helps much less with sounds or with choices.
- Fix the equipment. A high refresh rate screen, a wired mouse and wired headphones remove delay that no amount of training can.
- Warm up. The first series of the day is usually the slowest. Take one to settle in before you judge yourself.
- Sleep. It is the largest free improvement available.
Measure with the same test on the same device each time. Useful ones to rotate through are the visual reaction test, the sound reaction time test and the F1 reaction test.
The 100 ms line
How fast is too fast to be real? Athletics answers the question in its rules. Under World Athletics rules a sprinter who moves within 0.100 seconds of the gun has made a false start, on the basis that nobody can respond to a sound faster than that. The tests on this site use the same line: anything under 100 ms is treated as a guess and does not count.