Average reaction time by age

Each study used its own equipment and its own people, so the rows describe the shape of the change rather than one set of numbers to compare yourself with. The average for adults that our test uses is 230.8 ms, from the study in the third row.

Young children react slowly, and they improve fast. A study published in 2014 tested 550 girls and young women aged 7 to 20 on a computer, with a light and a sound to answer. Reaction times improved through childhood and levelled off at about 17, with the largest single jump between the ages of 7 and 8. Reactions that needed a choice were quickest about a year earlier^[2].

A much larger study online points the same way. It drew on 10,394 visitors to a research website, aged 10 to 69, and on the samples behind two standard adult test batteries. Some abilities, the authors found, peak and begin to decline around the end of secondary school; working memory peaked later, at around 30, and the speed of simple processing earlier than that^[3].

For a child, then, a result that is slower than an adult's is simply normal. The study of adults that our test compares you with began at age 18, so a child's result on our test is best compared with the same child's results over time.

The largest careful study of adults was published in 2015. It tested 1,469 volunteers aged 18 to 65 with a calibrated screen and mouse. Their simple reaction time grew by about 0.6 ms with each year of age, and it did not differ by sex or by education^[1]. A second experiment in the same paper, with 189 people aged up to 82, found the same rise with age.

The authors also split each reaction into two parts. The time to notice the target, which averaged 131 ms, did not change with age; the slowing came mainly from starting the movement^[1]. Older adults in that study saw the signal as quickly as younger ones and were a little slower to press.

A long study in Baltimore followed 1,265 volunteers aged 17 to 96, some of them for years. From about age 20, a simple reaction to a sound slowed by about 0.5 ms a year, and a reaction in which people had to decide whether to press at all slowed by about 1.6 ms a year^[4]. The more a task asks you to decide, the more age shows.

A survey of 7,130 adults in the United Kingdom found the same difference between kinds of task: simple reaction time changed little until around 50, while reactions with 4 choices slowed across the whole adult age range^[5].

A slowing of about half a thousandth of a second a year adds up to only a couple of hundredths over forty years. That is smaller than the difference between two ordinary people of the same age, and smaller than the delay a phone can add. In the adult study above, people of the same age were spread around the average by about 26.8 ms.

Speed is also not new. The authors of the adult study point out that the very first reaction time measurements, made by Francis Galton in the nineteenth century, recorded simple visual reactions below 190 ms in young people. Measured with equipment as precise as Galton's, people today are just as fast^[1].

Large online samples show the same pattern across the whole adult range. One web-based study gathered simple visual reaction times from 75,666 people aged 18 to 85 and studied how age, education and other factors went with them^[6].

Most of these studies compare people of different ages, each measured once, which could mix up age with the times people grew up in. The Baltimore study also tested the same people again over eight years. It saw the same slowing within each person, and answers that varied more from one try to the next as people got older^[4]. So the change is real, and it is gradual.

• If you are between about 20 and 60, your age changes your expected time by only a few hundredths of a second: the device you use and how rested you are matter as much.
• If you are older, expect to be a little slower on tests with a choice, such as a colour word test, than on a plain reaction test.
• If you are a child or a teenager, your times will usually improve as you grow, whether or not you practise.
• Whatever your age, compare your result with your own earlier results on the same device: that is the change you can trust.

A reaction test in a browser measures how fast you answered on that day and that device. It is for curiosity and self-reflection, and a slower time than someone else's says nothing about your health.

For the limits of human speed at any age, see what a really good reaction time is.