Brain Games · Speed
Reaction Time Test
When the screen turns green, click as fast as you can. Five tries, then your result.
In short
What is a reaction time test?
A reaction time test measures how fast you respond to a signal, in milliseconds (ms). Here you click the moment red turns green. The median online is about 273 ms, and a normal reaction time on a computer is roughly 200 to 300 ms. Around 80 ms of that is screen, mouse and browser delay, not you.
Below: the three modes, what your score means, braking distance, and how speed fits into an IQ test.
How to play
Three ways to test your speed
Pick a mode at the top and press Start. You get your average, your best try and where you stand, and you can send the score to a friend.
Classic
Simple reaction time, then choosing and stopping yourself.
- Wait while the screen is red. Click or tap the moment it turns green (the Space bar works too).
- Five tries make your score (pick 10 or 20 on the start screen for a steadier average). A click before green, or one faster than 100 ms, is a guess and is played again.
- Finish a level to open the next: Choice (click the half that turns green) and Trap (click on green, hold on blue).
Emergency stop
How fast you brake for one signal while ignoring the others.
- You are driving at 60 mph. Brake the moment the STOP sign appears: click, tap or press any key.
- The other signs (a 55 limit, a warning, parking) are traps. Braking for them does not count.
- After three stops you see how far a car would travel before you braked.
Brain lights
Speed and visual attention over 30 seconds.
- Nine rings sit on the board. Hit each one the moment it glows gold (keys 1 to 9 work too).
- A gold light fades after 1.5 seconds, so speed counts.
- Level 2, Avoid red: hitting a red light costs a point.
Your score
What your score means
Your Classic (Simple) average is placed on a curve of online players centred on the median of 273 ms reported by Human Benchmark.
| Your average | Faster than about |
|---|---|
| 200 ms | 96% |
| 225 ms | 86% |
| 250 ms | 69% |
| 273 ms | 50% |
| 300 ms | 30% |
| 350 ms | 8% |
| 400 ms | 2% |
These are our estimates, not test norms. Screens, mice and phones add their own delay, so compare yourself with yourself on the same device.
On the road
Emergency stop: time into distance
At 60 mph a car covers 88 feet (26.8 m) every second, so each tenth of a second adds about 9 feet before the brakes even start.
| Reaction time | Distance before braking |
|---|---|
| 0.25 sA fast click on screen | 22 ft 6.7 m |
| 0.40 sA slower click | 35 ft 10.7 m |
| 0.70 sA driver expecting the signal | 62 ft 18.8 m |
| 1.25 sUnexpected brake lights | 110 ft 33.5 m |
| 1.50 sA real surprise | 132 ft 40.2 m |
Driver times from Marc Green's review of driver studies (Green 2000). The distance is our calculation.
Normal times
What is a normal reaction time?
On a computer, 200 to 300 ms is normal for a simple test like Classic. Under 200 ms is fast: on our estimate, only about 4 in 100 players get there. Over 350 ms usually means a slow device, a tired mind or a missed signal.
Reaction speed test or reaction time test?
They are the same thing. A reaction speed test times the gap between a signal and your response, so a lower number means a faster reaction.
Simple and choice reaction time
Simple reaction time is one signal and one response, like Classic. Choice reaction time adds a decision, so it takes longer. That is why the Choice and Trap levels read slower than Level 1.
Reaction time by age
Reaction time is fastest in young adulthood and slows gently after that. Our table of average reaction time by age gives the numbers in milliseconds.
On the road
A driver who expects the brake light reacts in about 0.7 seconds; a surprise takes about 1.5 seconds. Emergency stop turns your own time into braking distance at 60 mph.
Ruler drop
What does the ruler drop test distance mean?
The ruler drop test turns the distance a ruler falls before you catch it into time, using t = √(2d/g). A catch at 20 cm means about 202 ms. You need only a 30 cm ruler and a friend.
Ruler drop distance and the time it represents
| Distance | Time | Distance | Time |
|---|---|---|---|
| 5 cm | 101 ms | 30 cm | 247 ms |
| 10 cm | 143 ms | 35 cm | 267 ms |
| 15 cm | 175 ms | 40 cm | 286 ms |
| 20 cm | 202 ms | 45 cm | 303 ms |
| 25 cm | 226 ms | 50 cm | 319 ms |
Our calculation from falling-object physics, ignoring air resistance.
Why it reads faster than a screen
There is no screen or mouse lag. In college football players, a falling rod averaged 203 ms and a computer test 268 ms (Eckner and colleagues, 2010).
One drop is not precise
Average several drops. In 51 older adults, a single ruler drop gave quite different results a week apart (Ferreira and colleagues, 2024).
The 40 cm line
In 903 adults in Sri Lanka, 95% caught the ruler at or under 40 cm, about 286 ms of fall (Rajapaksha and colleagues, 2023).
How to do the ruler drop test
- Hold your thumb and finger open, level with the zero mark of a hanging ruler.
- Your friend lets go without warning, at a different moment each time.
- Catch it as fast as you can and read the mark at the top of your fingers.
- Turn the distance into time with the table, and average five or more drops.
Online vs lab
Why do online reaction tests read slower than the lab?
Every online reaction time test includes your screen, mouse and browser delay. Robot tests found about 80 ms on average, and up to 100 ms on some set-ups (Anwyl-Irvine and colleagues, 2021). Much of it is a fixed offset, so compare your scores on the same device.
Average reaction times from different instruments
| Measurement | Average | Who and how |
|---|---|---|
| Falling rod, college football players | 203 ms | Eckner et al. 2010: 94 US Division I players |
| Calibrated computer test, delay taken off | 213 ms | Woods et al. 2015: 1,469 adults aged 18 to 65 |
| Calibrated computer test, as recorded | 231 ms | Same study, before taking off 17.8 ms of delay |
| Computer test, same football players | 268 ms | Eckner et al. 2010 |
| Human Benchmark, all visitors | 273 ms median | Over 81 million clicks, lag included |
| Keypad device, age 30 | 290 ms | Der and Deary 2017: 714 people in West Scotland |
Human Benchmark figures checked 30 September 2026.
What changes it
What changes your reaction time?
Sleep loss and age slow you down the most. Practice barely changes simple reaction time, and the evidence on caffeine and video games is mixed.
Sleep loss
After 17 to 19 hours awake, some tests were as bad as at a 0.05% blood alcohol level, and up to 50% slower (Williamson and Feyer, 2000). More in sleep loss and test performance.
Age
About 0.55 ms slower per year between 18 and 65 in a calibrated test, with more ups and downs from try to try after 60 (Woods and colleagues, 2015).
Practice
Simple reaction time barely trains. Baseball players were no faster than students on a simple test, though their Go/No-go times improved with practice (Kida and colleagues, 2005).
Caffeine
Small trials suggest it speeds responses through attention, with effects that vary by dose and task. See caffeine and test performance.
Video games
Contested. One review says action games cut reaction times without losing accuracy (Dye and colleagues, 2009); a 2018 meta-analysis found small or no effects. See video games and IQ.
Fatigue and waiting
Getting tired within a session, and how long you wait for the signal, both shift your times. That is why your score is an average of several tries.
Types of test
What types of reaction time test are there?
Reaction time is the time between a signal and the start of your response. Tests differ in the signal you get and in how many choices you have to make.
Reaction time tests, and where you find them here
| Type | What you do | On this page |
|---|---|---|
| Simple | One signal, one response | Classic, level 1 |
| Choice | Pick the right response for the signal | Classic, Choice level |
| Go/No-go | Respond to one signal, hold back on another | Classic, Trap level; Emergency stop |
| Visual search | Find the target among several, then respond | Brain lights |
| Ruler drop | Catch a falling ruler | The ruler drop table |
| Driving | Brake for a hazard | Emergency stop |
| Sound | Respond to a tone instead of a light | Not here yet |
Reaction or reflex?
Some sites call this a reflex test. Strictly, a reflex such as the knee jerk needs no decision. This test times a voluntary response, which is why it takes longer.
Like Human Benchmark?
Classic uses the same red-to-green idea as Human Benchmark’s test, with five counted tries. The Choice, Trap and Emergency stop levels then add decisions on top.
Improve it
How can you improve your reaction time?
You can improve your reaction time score more than your nervous system. A faster screen, enough sleep and steady focus help most. Simple reaction time barely trains, but choice and Go/No-go times can (Kida and colleagues, 2005).
How long one screen frame lasts
| Refresh rate | One frame |
|---|---|
| 60 Hz | 16.7 ms |
| 75 Hz | 13.3 ms |
| 120 Hz | 8.3 ms |
| 144 Hz | 6.9 ms |
| 240 Hz | 4.2 ms |
| 360 Hz | 2.8 ms |
A signal can wait up to one frame before it appears, so a faster screen trims a few milliseconds of the delay you measure.
Set up before you start
Use a computer and a wired mouse if you can, and rest your finger on the button. Look at the centre of the screen, and do a couple of practice tries first.
Sleep and timing
Test when you are rested: after a short night your times rise. Our guide to sleep and IQ covers what lost sleep does to thinking.
Train choices, not raw speed
Reaction time exercises that add a decision, such as the Choice and Trap levels, are the kind that improve with practice. One fast try is luck; a lower average is real progress.
For gaming
In games, aim and decisions matter more than raw speed. A higher refresh rate and lower input lag take milliseconds off the screen side of every reaction.
Fastest times
What is the fastest human reaction time?
There is no official world record for reaction time. The best-known line is in sprinting: World Athletics treats a start less than 0.100 seconds after the gun as a false start.
Sprinters
In a lab study of nine sprinters and ex-sprinters, five averaged under 100 ms in at least one condition, timed from the gun to force on the blocks (Pain and Hibbs, 2007).
F1 drivers
Drivers’ own figures are statements, not measurements. In 2017 Sebastian Vettel said that “normally, the reactions are 0.2s for everyone.”
Gamers
We found no trustworthy figure for a typical gamer. Lab work does find action-game players a little faster on some tasks (Dye and colleagues, 2009).
Your best try
A single very fast try is often luck. Your score is the average of your counted tries, and anything under 100 ms counts as a guess.
Skills
What the test uses
Response time
How quickly you notice a signal and move. Simple reaction time is the cleanest measure of it.
Inhibition
Holding back when you should not respond. The Trap level and the fake road signs test it, like a Go/No-Go task.
Processing speed
How fast you take in information and act on it. Tests such as the WAIS score it as its own index, next to reasoning and memory.
And IQ
Does a fast reaction time mean a high IQ?
Only a little. In three large Scottish studies, faster reaction times went with higher IQ scores. But the link was modest: a correlation of about 0.3 for simple and 0.5 for four-choice reaction time, where 1 is a perfect match.
Speed is one of the five areas a modern IQ test reports, called processing speed. Our guide to processing speed and IQ explains the research, and an online IQ test puts speed, reasoning and memory into one score.
The five areas of a modern IQ test
- Verbal comprehensionWord knowledge and reasoning in words
- Visual spatialSeeing and turning shapes in your mind
- Fluid reasoningFinding the rule in a new problem
- Working memoryHolding information and using it
- Processing speedQuick, accurate simple workClosest to this game
The five primary index areas of the WISC-V (children, 2014) and the WAIS-5 (adults, 2024). See WAIS-5 index scores explained.
FAQ
Reaction time test: questions people ask
What is a good reaction time?
On a computer, roughly 200 to 300 ms is ordinary; the device changes the number by tens of milliseconds, so compare like with like.
How accurate is an online reaction time test?
It includes screen, input and browser lag: robot tests found about 80 ms on average, and Human Benchmark says its own scores are affected by latency.
How is my score worked out?
Your score is the average of your counted tries, in milliseconds. A click before the signal, or one faster than 100 ms, is treated as a guess and that try is played again; a try with no click within 3 seconds does not count either. Your best average and best single try are saved in this browser.
Why are my times slower on a phone?
A touch screen adds its own delay, so the same person usually scores slower on a phone than with a mouse. Compare yourself on the same device.
What do the Choice and Trap levels test?
Choice is a choice reaction time task: you must decide which side turned green, and choosing always takes longer than a simple reaction. Trap is a Go/No-Go task: you click on green and hold back on blue, which tests how well you stop yourself.
What is the average reaction time when driving?
About 0.7 second when expected, 1.25 seconds when unexpected and 1.5 seconds for a surprise (Green 2000); road design uses 2.5 seconds.
Can you improve your reaction time?
Simple reaction time barely changes with practice; sleep, attention and the task matter more.
Does reaction time measure IQ?
Only weakly: correlations of −0.27 to −0.32 for simple and −0.44 to −0.53 for four-choice reaction time in three Scottish cohorts. Speed is one strand of a full IQ test, next to reasoning and memory.
How do you do the ruler drop test?
Have a friend drop a ruler without warning, catch it, read the distance and convert it: 20 cm is about 202 ms. Average several drops.
How do I challenge a friend?
After a round, send your score by WhatsApp, Telegram, X, Facebook, Reddit, LinkedIn or email, or copy the link. Your friend plays the same mode and sees both scores. The link carries only the score, the mode and the first name you type, if any.
Is a reaction speed test the same as a reaction time test?
Yes. Both time the gap between a signal and your response, in milliseconds. A lower number is a faster reaction.
What is the world record for reaction time?
There is none. Sprinting sets the best-known line: World Athletics treats a start under 0.100 seconds after the gun as a false start.
How can I improve my reaction time?
Test on a fast screen when you are rested, and practise tasks with a decision in them, like the Choice and Trap levels. Simple reaction time changes little with practice.
Is my score saved or sent anywhere?
Your scores are kept in your own browser and are not sent to us. There is no signup.
Sources
The research behind this page
- 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, 9, 131. doi:10.3389/fnhum.2015.00131
- Der, G., & Deary, I. J. (2017). The relationship between intelligence and reaction time varies with age: results from three representative narrow-age age cohorts at 30, 50 and 69 years. Intelligence, 64, 89–97. doi:10.1016/j.intell.2017.08.001
- Anwyl-Irvine, A., Dalmaijer, E. S., Hodges, N., & Evershed, J. K. (2021). Realistic precision and accuracy of online experiment platforms, web browsers, and devices. Behavior Research Methods, 53(4), 1407–1425. doi:10.3758/s13428-020-01501-5
- Eckner, J. T., Kutcher, J. S., & Richardson, J. K. (2010). Pilot evaluation of a novel clinical test of reaction time in National Collegiate Athletic Association Division I football players. Journal of Athletic Training, 45(4), 327–332. doi:10.4085/1062-6050-45.4.327
- Rajapaksha, S., et al. (2023). The establishment of a population-specific reference value for the ruler drop test for the clinical assessment of reaction time. Journal of Forensic and Legal Medicine, 96, 102525. doi:10.1016/j.jflm.2023.102525
- Ferreira, S., et al. (2024). Validity and reliability of a ruler drop test to measure dual-task reaction time, choice reaction time and discrimination reaction time. Aging Clinical and Experimental Research, 36, 61. doi:10.1007/s40520-024-02726-6
- Green, M. (2000). “How long does it take to stop?” Methodological analysis of driver perception-brake times. Transportation Human Factors, 2(3), 195–216. doi:10.1207/sthf0203_1
- Williamson, A. M., & Feyer, A. M. (2000). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 57(10), 649–655. doi:10.1136/oem.57.10.649
- Kida, N., Oda, S., & Matsumura, M. (2005). Intensive baseball practice improves the Go/Nogo reaction time, but not the simple reaction time. Cognitive Brain Research, 22(2), 257–264. doi:10.1016/j.cogbrainres.2004.09.003
- Dye, M. W. G., Green, C. S., & Bavelier, D. (2009). Increasing speed of processing with action video games. Current Directions in Psychological Science, 18(6), 321–326. doi:10.1111/j.1467-8721.2009.01660.x
- Sala, G., Tatlidil, K. S., & Gobet, F. (2018). Video game training does not enhance cognitive ability: a comprehensive meta-analytic investigation. Psychological Bulletin, 144(2), 111–139. doi:10.1037/bul0000139
- Human Benchmark. Reaction time statistics (median 273 ms, mean 284 ms), checked 30 September 2026. humanbenchmark.com
- Pain, M. T. G., & Hibbs, A. (2007). Sprint starts and the minimum auditory reaction time. Journal of Sports Sciences, 25(1), 79–86. doi:10.1080/02640410600718004
- Motorsport.com: Vettel on start reaction times (2017). www.motorsport.com
The full picture
Your speed is one piece. Now see the whole picture.
Each game looks at one skill. The IQ test brings speed, reasoning and memory together in one score, with your percentile and a certificate.