Reaction Time Test

Wait for the box to turn green, then click, tap or press Space as fast as you can. After 5 attempts you get your average and best reaction time in milliseconds.

Last
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Average
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Best
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How to use the reaction time test

  1. Click or tap the box, or press Space while it's selected, to start.
  2. The box turns red. Wait, and don't press yet.
  3. When it turns green, press as fast as you can. Your time appears in milliseconds.
  4. Press again to start the next attempt. After 5 attempts you see your average and best.

If you press while the box is still red, you get "Too soon!" and that attempt isn't counted.

How the test works

After you start, the test waits a random time between 1.5 and 5 seconds, picked with your browser's cryptographic random number generator. Then it turns the box green and notes the exact moment of the animation frame that draws the green, using requestAnimationFrame and the high-resolution timer performance.now().

Your press is timed when the button goes down, not when you let go, so holding the button doesn't slow you down. Your reaction time is the press time minus the green time. The average is the mean of your 5 attempts and the best is the lowest. Nothing leaves your browser.

The box changes color instantly, with no fade, so a slow transition can't add to your time.

What adds to your measured time

Every online reaction test measures your reaction plus your setup's delay. Here's where that extra time comes from:

Since these delays differ between setups, only compare results taken on the same device, screen and mouse.

Refresh rate and polling rate: time between updates

The time between updates is 1000 ÷ the rate in hertz. It shows how often your screen and mouse can pass along something new.

Monitor refresh rateTime between frames
60 Hz16.7 ms
120 Hz8.3 ms
144 Hz6.9 ms
240 Hz4.2 ms
360 Hz2.8 ms
Mouse polling rateTime between reports
125 Hz8 ms
250 Hz4 ms
500 Hz2 ms
1,000 Hz1 ms
8,000 Hz0.125 ms

Want to test your speed in a different way? Try the CPS Test for clicking speed or the APM Test for clicks and key presses together.

Frequently asked questions

What is a good reaction time on this test?

There's no single good number, because your result includes your monitor, mouse and browser delay as well as your own reaction. The fairest comparison is with yourself: take the test on the same device and watch your 5-attempt average over time.

Why does the test say too soon?

You pressed before the box turned green. The wait is random, so pressing early means you guessed. That attempt doesn't count, and you can try again right away.

Does my monitor refresh rate affect my reaction time?

Yes. A monitor shows a new image once per refresh, every 16.7 ms at 60 Hz and every 4.2 ms at 240 Hz, and its pixels need time to change. That delay lands in your result, so a slower display can add milliseconds. Check your rate with the FPS & Refresh Rate Test.

Why is the wait before green random?

The wait is a random time between 1.5 and 5 seconds, so you can only react, not predict. It's picked with your browser's cryptographic random number generator, the same one used for security, so there's no pattern to learn.

Why does the test use 5 attempts?

An average of 5 tries is steadier than any single try. Your best attempt shows your top speed, and your average shows the speed you can repeat.

Can I take the reaction time test on a phone?

Yes. Tap the box when it turns green. Touchscreens check for touches at their own rate, which adds a little delay, so compare phone results with phone results.

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