Reaction Time Test

How to use the reaction time test

Tap the big box, click it or press Space to begin. The box fills in and says Wait for green. After a random pause of 1.5 to 5 seconds it turns green: tap as fast as you can. Your time appears in milliseconds, and the next tap starts the next attempt. If you tap before the green shows, you see Too soon; that attempt does not count, and your next tap starts a fresh wait. Because the pause is random every time, guessing the moment does not pay off.

A round is 5 attempts by default; pick 3 or 10 at the top. Each attempt is listed under the box, and at the end of the round you get your average, your fastest and your slowest time. Your best average for each mode and round length and your fastest single attempt are kept in your browser, along with your last 300 results. Download CSV saves them with the date and mode, Undo takes back the last saved round, and Clear results wipes the list (with an undo button in case you change your mind).

Three modes: visual, sound and choice

Visual is the classic reflex test: the box turns green. Sound keeps the screen unchanged and plays a short beep instead, so you react to what you hear. Headphones, Bluetooth speakers and the audio output of your device add their own delay before the beep reaches you, and that delay is part of the time shown, so for a fair reaction speed test use the same wired headphones or the built in speaker every time. Choice shows green or red at random: tap only on green and hold still on red. A tap on red counts as a mistake, holding still for one second counts as a right answer, and the round shows your accuracy as a percentage next to your times.

Times from different modes are kept apart, since a sound and a colour are not the same task. A choice round is usually slower than a visual one because you have to decide before you move. For a motor racing style start, where five red lights come on and then go out together, try the start lights reaction test.

What affects your result

The time shown is everything between the moment the page shows the green (or starts the beep) and the moment your press reaches the browser. Several things in that chain add milliseconds that have nothing to do with your reflexes:

• Screen refresh rate. A screen only redraws a set number of times per second, so the green can appear a few milliseconds after the page asked for it. A slower screen adds more.
• Input device and touch delay. Mice, keyboards and touch screens each take their own time to report a press. A touch screen can add more than a wired mouse or keyboard.
• Audio latency. In sound mode the beep passes through the audio system of your device, and wireless headphones can add a long delay.
• Browser timer precision. Browsers round their clocks slightly for privacy reasons, which can shift a time by a small amount.

This is why scores from different devices are not directly comparable. To follow your own progress, use the same device, the same input and the same mode each time, and look at your averages rather than one lucky tap. The timing uses the time stamp of your press and the frame that drew the green, so a busy page cannot add its own delay on top. We do not publish an average human figure here, because no single number would fit every device and setup.

Keyboard shortcuts

• Space or Enter: start an attempt, and react when it is time
• 1, 2, 3: visual, sound or choice mode
• R: new round (drops an unfinished round, with undo)
• U or Ctrl+Z: undo the last saved round or clearing
• F: full screen
• M: page sounds on or off (the beep in sound mode always plays)

Holding a key down never counts twice. If you want to measure how fast you can tap rather than how fast you respond, try the CPS test for clicks per second, the spacebar counter for key presses, or the mouse click counter to check each mouse button.

Questions

More in Counters

• Click Counter
• Tally Counter
• Multi Counter
• Days Since Counter
• Traffic Counter
• Bird Counter
• CPS Test
• Spacebar Counter
• Mouse Click Counter
• Start Lights Reaction Test
• Differential Cell Counter

Put this reaction time test on your website

Free for classrooms, clubs, blogs and shops: paste this code into any page. It works the same inside your site, and counts stay in each visitor's own browser. For a dark version, add ?theme=dark after /reaction-time-test/ in the code.