CheckMyBits

Reaction Time Test – How Fast Are Your Reflexes?

Click the moment the box turns green. Five rounds, averaged — because a single attempt tells you almost nothing about reaction time, which varies naturally by 40 to 60 milliseconds between tries. It works as a quick reflex test, and a simple way to compare your reaction speed over time.

    Runs in your browser. Nothing is recorded or uploaded.

    How to test your reaction time

    1. Click the box once to begin a round. It turns red.
    2. Wait. The green appears at a random point between 1.5 and 5 seconds, so it cannot be anticipated.
    3. Click the instant it turns green. Clicking early restarts that round rather than scoring it.
    4. Repeat for five rounds. Your average and best are reported.
    5. Run it a few times. Reaction time is noisy, and one attempt is not a measurement.

    What your result means

    Why your hardware is part of the score

    This is the thing most reaction tests leave out, and it matters more than people assume. The number you see is your reaction plus the time your screen took to show the green plus the time your mouse took to report the click.

    On a 60Hz monitor the image can wait up to 16.7 milliseconds for the next refresh before it is visible at all. On 144Hz that falls to about 7ms, and on 240Hz to around 4ms. Panel response time adds more, and a wireless mouse polling at 125Hz adds up to 8ms on top of that. Altogether that is 20 to 50 milliseconds of equipment sitting inside a human figure of roughly 200 to 250.

    The practical consequence: the same person scores meaningfully better on better hardware. Comparing your own attempts on one machine is valid. Comparing your score against someone on a different setup is mostly comparing the setups. You can check what your own screen is actually running at with the refresh rate test — a surprising number of people discover their 144Hz monitor is set to 60.

    Want a better score? What actually works

    The things that genuinely help
    1. Sleep. The largest single factor, and the least popular answer. Tiredness costs 30 to 50ms easily.
    2. Raise your refresh rate. If your monitor supports more than 60Hz and is set to 60, that is 10ms you are giving away before you do anything else.
    3. Use a wired mouse, or raise the polling rate. 1000Hz polling reports a click within 1ms; 125Hz can take 8.
    4. Sit closer and look at the centre. Peripheral vision detects change more slowly than central vision.
    5. Rest your finger on the button. Travel time counts, and a hovering finger adds it to every round.
    Things that do not help as much as claimed
    1. Reaction training apps. They make you better at that app. General reaction speed is largely fixed by biology.
    2. Caffeine, past a point. A modest dose helps alertness; more increases variability, which makes the average worse.
    3. Trying harder. Tension slows movement. A relaxed hand is consistently faster than a braced one.
    4. Anticipating. It produces better-looking numbers and measures nothing. The randomised delay exists to stop it.
    If your score is much worse than expected
    1. Check your refresh rate and whether anything is throttling it — battery saver caps it on most laptops.
    2. Close other tabs. A busy machine delays the colour change itself.
    3. Try the keyboard instead of the mouse, and compare. A large gap points at the mouse.
    4. Check your mouse is not double-firing with the mouse test — a failing switch adds unpredictable delay.

    Frequently asked questions

    How do I test my reaction time?
    Wait for the box to turn green, then click as soon as it does. After five rounds you get your average reaction time in milliseconds.
    Is this a reflex test, and how fast are my reflexes?
    Yes. It measures how quickly you respond to a visual cue. Compare your average with the answer to "What is a good reaction time?" below, and remember that your display and mouse add a little delay to the score.
    What is a good reaction time?
    Most people land between 250 and 300 milliseconds on a test like this. Under 220ms is genuinely fast and typical of people who play competitive games regularly. Under 180ms is exceptional and worth checking twice, because the most common cause of a very low score is anticipating the colour change rather than reacting to it. Above 350ms is slower than average, but tiredness, caffeine, screen size and even time of day all move this figure by 30 to 50ms, so a single result means very little.
    Does my monitor affect my score?
    Yes, and more than most people expect. On a 60Hz screen the green can take up to 16.7 milliseconds to appear after the browser has drawn it, because that is how long you wait for the next refresh. On a 144Hz screen that drops to about 7ms, and on 240Hz to 4ms. Add input lag from the panel itself and a wireless mouse's polling interval, and the same person can score 20 to 40ms better purely from better hardware. If you want a fair comparison with a friend, compare on the same machine.
    Is this measuring my reflexes or my equipment?
    Both, unavoidably. What you see is your reaction plus display latency plus input latency. A human visual reaction is roughly 200 to 250ms, and the hardware typically adds 20 to 50ms on top. There is no way to separate them in a browser, so the honest answer is to treat the number as your reaction on this setup, not an absolute measure of you. Comparing your own score across sessions on the same machine is meaningful; comparing across machines is not.
    Why does it say I clicked too early?
    Because you clicked while the box was still red, which means you were anticipating rather than reacting. The wait before green is randomised between 1.5 and 5 seconds specifically to prevent that — a fixed delay would be learnable within two rounds and the test would measure your timing rather than your reflexes. An early click restarts that round rather than scoring it.
    Can I improve my reaction time?
    A little, and less than most training products claim. Practice improves familiarity with a specific task rather than general reaction speed, so you will get better at this test faster than you get better at anything else. The things that genuinely move the number are unglamorous: sleep, not being hungover, and sitting closer to a screen with a higher refresh rate. Age matters too — reaction times peak in the early twenties and decline gradually after.
    Why do I get different scores each time?
    Because human reaction time is naturally variable. Round-to-round spread of 40 to 60ms is completely normal, which is exactly why this test takes five rounds and averages them rather than scoring a single attempt. If you want a reliable figure, run it three times and take the middle result.
    Does this work on a phone?
    Yes, and touch screens are generally a little slower than a mouse because of how touch events are processed and reported. Expect perhaps 20 to 30ms worse than you would score on a desktop with a wired mouse. The comparison between your own attempts on the same phone is still perfectly valid.
    Can I use the keyboard instead of clicking?
    Yes — Space or Enter both work. Some people are reliably faster on a key than a mouse button, often because a keyboard switch has a shorter travel than a mouse switch. Pick one and stick to it if you are comparing attempts.

    Fix-it steps last checked against current operating system releases on 18 October 2026.