Reaction time test

Measure your reaction time in milliseconds — corrected for your own screen and input lag.

Press space or enter instead of tapping if you are using a keyboard.

Trial 0 of 5

Percentiles are modelled from published population averages, not from a medical reference range. How the numbers are worked out.

A reaction time test that accounts for your screen

This reaction time test measures how long it takes you to respond to something you can see, in milliseconds. The panel above waits a random interval, turns green, and the clock runs until your tap registers. Five trials give you an average, your best single attempt, and the spread between them — and the spread tells you as much as the average does.

What makes this one different from the reaction test you have used before is what it does with your hardware. Every screen holds a change back until its next refresh, so on a 60 Hz display a stimulus waits an average of 8.3 milliseconds before your eyes can possibly see it. On a 144 Hz gaming monitor that wait is 3.5 ms. That difference is baked into every reaction time test you have ever taken, unlabelled, and it is a large part of why the same person scores differently on a phone and a desktop.

This test measures your display's refresh rate from the browser's own frame clock and shows you both numbers: the raw measurement, and the measurement with that display wait removed. It does not pretend to remove the rest — your mouse, touchscreen, operating system and browser all add delay that a web page cannot measure, and a test that claims otherwise is guessing.

Four ways to test

The tabs above the panel switch between four modes. They all use the same timing code and the same scoring, so their results are directly comparable against each other.

  • Visual. The classic reaction time test. The panel turns green, you tap. This is the mode that produces the number people quote.
  • Audio. A tone plays instead. Almost everyone is 30 to 50 ms faster here, because sound is converted to nerve signals faster than light is. Use wired audio — Bluetooth adds latency that lands in your score.
  • Choice. Some signals say tap and some say hold. Now you have to read the signal before acting, which costs 50 to 150 ms and measures your decision rather than only your speed.
  • Aim. A target appears at a random point and you have to hit it. The gap between this and your visual score is the time you spend finding and reaching a target, which is the part that actually improves with practice.

What your result means

A healthy adult tapping a screen usually lands between 200 and 300 milliseconds on the visual test, with a median near 273 ms. Under 200 ms is genuinely fast. Over 350 ms is more often a phone, a distraction or a short night than anything about your nervous system.

Your result is placed against an age band because reaction time changes across a lifetime — it peaks in the late teens and early twenties and slows by roughly a millisecond a year through adult life. Pick your band under the tool and the percentile updates. That percentile comes from a model anchored to published population averages for simple reaction time, not from a measurement of the people who have used this site, and it is not a clinical measure of anything.

Look at your spread as well as your average. Five trials between 240 and 260 ms describes someone who was focused throughout. Trials at 190, 200, 210, 250 and 400 average out to the same number and describe someone who lost attention once. In every real activity — driving, sport, games — the lapse is what matters, because it is the one that arrives when you needed the other four.

Why false starts are thrown away

Tap before the panel turns green and the trial is discarded, not scored. So is any trial faster than 100 ms. Nerve transmission, processing and muscle activation cannot complete faster than that, so a sub-100 ms result is a guess that happened to land after the signal instead of before it. Athletics uses the same threshold: a sprint start under 100 ms is ruled a false start on exactly this reasoning.

Counting guesses would reward anticipating the timing, which is the opposite of what a reaction time test is for. The wait before each signal is randomised between 1.4 and 4.4 seconds so that the interval cannot be learned, and your false-start count is shown beside your average so you can see what was dropped.

Getting a score that is actually comparable

  • Use the same device each time. A phone, a laptop trackpad and a wired mouse on a gaming monitor produce meaningfully different numbers for the same person.
  • Warm up. Your first run of the day is reliably 10 to 20 ms slower than your third, and testing cold tells you about being cold.
  • Take the five-trial average rather than your best single attempt. One good trial is partly luck.
  • Treat any difference under about 15 ms as noise. If you want to test whether coffee or a bad night changed you, run five trials before and five after, on the same device at the same time of day.
  • Test rested if you want your ceiling, and tired if you want to know what your tired self is like. Both are useful; they are not the same number.

Nothing leaves your browser

The entire test runs on your device. Your trial times, the age band you pick and your last ten runs are stored in your own browser and are never uploaded — there is no account, no login, and no server-side record of anyone's scores. Clearing the history in the tool, or clearing site data in your browser, deletes them for good.

That is also why your history does not follow you between devices. It is a deliberate trade: a record you own on the device you tested on, rather than a profile on a server you have to trust.

Frequently asked questions

What is a good reaction time?

On a browser reaction time test, 200 to 280 ms is normal for a healthy adult, 180 to 220 ms is fast, and under 180 ms is exceptional. Over 350 ms usually reflects the device, tiredness or distraction rather than ability. Consistency matters as much as the average: five trials clustered within 30 ms is a better result than a faster average with one very slow trial in it.

What is the average human reaction time?

For a simple visual reaction — one signal, one response — the average adult lands between 200 and 300 milliseconds, with large public aggregates putting the median near 273 ms. Auditory reaction is faster, typically by 30 to 50 ms. Choice reaction, where you have to decide which signal you saw, is slower by 50 to 150 ms.

Why is my reaction time slower on my phone?

Three reasons stack up. Most phone screens refresh at 60 Hz, so a stimulus waits an average of 8.3 ms to appear against 3.5 ms on a 144 Hz monitor. Touchscreens sample your finger less often than a wired mouse reports. And your finger travels further and lands less precisely than a mouse click. The same person commonly scores 20 to 40 ms slower on a phone without being any slower.

Does this test correct for input lag?

It corrects for the part it can calculate. The test measures your display's refresh rate from the browser frame clock and subtracts the average wait for the next refresh — half a frame. It cannot measure your panel's processing delay, your mouse or touchscreen polling, the operating system's input handling or your browser's event dispatch, so those remain in your score and are not silently guessed at.

How many trials should I do?

Five, which is what a run here gives you. One trial is noise — a blink or a notification decides it. Five produces a stable average and, more usefully, a spread you can read. If you are comparing two conditions such as before and after coffee, run five trials in each condition on the same device rather than adding more trials to one run.

Why was my fastest attempt thrown out?

Any trial under 100 ms is discarded as anticipation. Signal transmission, processing and muscle activation cannot be completed faster than that, so a result below the floor is a guess that landed after the signal rather than a response to it. Athletics applies the same rule: a sprint start under 100 ms is a false start regardless of whether the athlete heard the gun.

Is reaction time the same as reflexes?

No. A true reflex, like a knee jerk, turns around in the spinal cord without reaching your brain and takes 30 to 50 ms. What this test measures is a voluntary reaction that goes through your visual cortex and motor cortex, which takes around 250 ms. The words are used interchangeably in everyday speech, but the numbers are not comparable.

Can I improve my reaction time?

Simple reaction time is close to a fixed property of your nervous system and moves only a few percent with practice. What does improve substantially is decision speed on a familiar task, anticipation within a specific activity, and consistency. Sleep is the largest single-day factor, warming up is worth 10 to 20 ms, and better hardware often buys more milliseconds than any training programme.

How does reaction time change with age?

It is fastest in the late teens and early twenties, then slows gradually through adult life at roughly a millisecond a year. The median moves from about 262 ms in the 18 to 24 band to about 358 ms over 65. Variability increases more than the median does, so the occasional very slow trial becomes the practical difference rather than the average.

Why is the audio test faster than the visual one?

Sound is converted into nerve signals mechanically by hair cells in the cochlea and reaches the auditory cortex in 8 to 10 ms. Light has to go through a chemical cascade in the retina first, so vision takes 20 to 40 ms to reach the cortex. The head start is in the sensory hardware, not in the travel time of the signal through the air.

Do Bluetooth headphones affect the audio test?

Substantially. Wireless audio adds 100 to 250 ms of output latency depending on the codec, and all of it lands inside your measured reaction time. No web page can detect or subtract it. Use wired headphones or your device speakers for the audio mode; a Bluetooth score is only good for comparing you against yourself on the same headphones.

Is my data stored anywhere?

No. Everything runs in your browser. Your trial times, chosen age band and last ten runs are kept in your own browser's local storage and never sent to a server. There is no account and no profile. Clearing the history in the tool or clearing site data in your browser removes them permanently, and nothing carries across to another device.

Can I use this to check whether I am fit to drive?

No. A browser test measures a response to a signal you are already watching for. Driving depends on attention, scanning and hazard recognition, and alcohol and fatigue degrade those before and beyond simple reaction speed. The test is a good demonstration of how far a car travels in a quarter of a second; it is not an assessment of anything.

Does the test work on a keyboard?

Yes. The panel is a button, so it takes focus with the Tab key and responds to space or enter. Keyboard input is often slightly faster and more consistent than a mouse, so keep the input method the same across any comparison you care about.