Reaction Time Test

Wait for the panel to turn green, then tap, click or press Space as fast as you can — five rounds give you an average in milliseconds.

Five rounds, lower is better

Red means wait. The moment it turns green, tap, click or press Space.

  1. Round 1—
  2. Round 2—
  3. Round 3—
  4. Round 4—
  5. Round 5—

Example average of 5 rounds

273 ms average

Best round
251 ms
Slowest round
298 ms
False starts
0

42 ms slower than the 231 ms average measured with calibrated lab equipment in 1,469 adults aged 18–65; your screen and input device add some of that (see below).

  1. Round 1284 ms
  2. Round 2 · best251 ms
  3. Round 3298 ms
  4. Round 4263 ms
  5. Round 5270 ms

Your own score card appears here after round 5, with a link to challenge a friend.

How this score was worked out
  1. Each round measures the time from the green panel appearing to your press, using the browser’s high-resolution clock, rounded to the nearest millisecond.
  2. Your 5 rounds: 284 ms, 251 ms, 298 ms, 263 ms, 270 ms.
  3. Average = (284 + 251 + 298 + 263 + 270) ÷ 5 = 1,366 ÷ 5 = 273.2 ms, shown as 273 ms.
  4. Best = your fastest round, 251 ms. Slowest = 298 ms, a spread of 47 ms.
  5. No false starts: every press came after the panel turned green.

How to take the reaction time test

Tap or click the panel to begin. It turns red: keep still. After a random wait of 1.5 to 5 seconds it turns green and says “Tap!” — press as fast as you can with a finger, the mouse, or the Space or Enter key. Your time appears on the panel; tap again for the next round. After five rounds you get your average, best and slowest times. Press during the red wait and you’ll see “Too soon!” — that round is replayed, so a false start never counts.

How your reaction time is measured

reaction time = moment you press − moment the green panel is drawn average = (round 1 + round 2 + round 3 + round 4 + round 5) ÷ 5

Both moments come from the browser’s high-resolution clock (performance.now(), defined by the W3C High Resolution Time standard). The press is time-stamped when your finger, mouse button or key goes down, not when it comes back up. Timing starts on the first screen frame after the panel has been painted green, which is as close as a web page can get to when the color actually appears. Each time is rounded to the nearest millisecond.

A press less than 100 ms after green counts as a false start too. Reaction time research generally treats responses that fast as anticipations — the finger was already moving before the signal could have been seen — and excludes them rather than letting a lucky guess set a record.

Worked example

Your five rounds are 284, 251, 298, 263 and 270 ms. The average is (284 + 251 + 298 + 263 + 270) ÷ 5 = 1,366 ÷ 5 = 273.2 ms, shown as 273 ms. Your best round is 251 ms and the slowest 298 ms, a spread of 47 ms. That is the example card above.

What is a normal reaction time?

A 2015 study measured simple visual reaction time in 1,469 people aged 18 to 65 with carefully calibrated equipment. The average was 231 ms, or 213 ms after subtracting the delay the researchers measured in their own hardware. Reaction time got slower with age, by about 0.55 ms per year, and did not differ by sex or education. Your score card compares your average with the 231 ms figure, since that is the one that still includes equipment delay — as yours does.

Why your device adds time

Every score on a web page includes some delay from the device, typically tens of milliseconds and sometimes more:

  • The screen. A 60 Hz display redraws every 16.7 ms, so green can only appear at the next redraw, and many screens (especially TVs outside “game mode”) add processing time on top.
  • The input. Touchscreens check for fingers many times a second rather than continuously, and wireless mice and keyboards can add a little delay of their own. A 2012 study found that commercial touch devices of the time took 50 to 200 ms to update the screen after a touch.
  • The computer. A busy browser or a slow phone may take a little longer to process the press.

So compare scores taken on the same device, and don’t read too much into a few milliseconds. To shave off real time: use a wired mouse or keyboard, rest your finger on the button, look at the center of the panel, and stay relaxed rather than tense. Then try the CPS test or the typing test, or use the stopwatch for longer timings.

Frequently asked questions

What is a normal reaction time?

In a lab study of 1,469 adults aged 18 to 65 using calibrated equipment, the average simple visual reaction time was 231 ms (213 ms after subtracting the equipment’s own delay), and it slowed by about half a millisecond per year of age. On a phone or an ordinary computer, expect your score to be somewhat higher because the screen and input add delay.

Why is my reaction time slower on my phone?

A touchscreen has to sense your finger and the screen has to redraw before the browser can time anything, and both take time. Phones, laptops and TVs differ, so only compare scores taken on the same device.

Why did it say “Too soon”?

Either you pressed before the panel turned green, or you pressed less than 100 ms after it did. Reaction time research treats responses that fast as anticipations — guesses made before the brain could have processed the signal — so the round is replayed instead of counted.

Can I learn when the green light is coming?

No. Each wait is a fresh random whole number of milliseconds between 1,500 and 5,000, drawn with your browser’s cryptographic random number generator (crypto.getRandomValues), so there is no pattern to learn.

Is it better to use a mouse, keyboard or touch?

Use whatever you will use to compare, and stick with it. The test counts the moment a button, key or finger goes down, not when it comes up. A wired mouse or keyboard often adds less delay than a touchscreen.

How does the challenge link work?

After round 5, your average and best times are added to the page address. Challenge a friend shares that link; your friend sees your score above the test. Lower is better. Nothing is stored on a server.

Sources

Last reviewed · Built and checked by the Reeliy team · How we test our tools