Reaction Time Test

When the red box turns green, tap it as fast as you can. After five rounds you'll see your average and your fastest time.

How it works

1Tap the blue box to start. It turns red: keep your finger ready and wait.
2After a random pause of 1.5 to 5 seconds it turns green. Tap as fast as you can.
3Tapping while it's still red, or within 100 ms of green, counts as too soon and the round starts over.
4After five rounds you get your average, your fastest tap and a rating. On a computer you can press the Space bar or Enter instead of tapping.

What affects your reaction time

Most adults react to a simple visual signal in about 200–300 ms. That covers your eyes noticing the change, your brain deciding to move and the signal travelling to your finger.
Your device adds a little too. A 60 Hz screen only redraws every 16.7 ms and a touchscreen takes a moment to register a tap, so phone results usually run a bit slower than lab measurements.
Reaction time tends to be fastest in your late teens and twenties and slows gradually with age. It also shifts over the course of a day.
Lack of sleep hurts. One well-known study found that after 17 to 19 hours awake, people did as badly on some tests as they did with a blood alcohol level of 0.05%.
We react to sound a little faster than to light. In athletics, a sprinter who moves within 0.1 seconds of the gun is charged with a false start, because that's too fast to be a real reaction.

Questions

What's a good reaction time?

On a simple test like this, most adults land between 200 and 300 ms. Under 250 ms is quick, and staying under 200 ms is excellent. On a phone, expect to be a little slower than on a computer with a good mouse because of touch and screen delay.

Why do I get a different result every time?

Swings of a few tens of milliseconds from one tap to the next are normal. Attention, how ready your finger is and the length of the random pause all play a part. That's why the test uses the average of five rounds instead of a single tap.

Why does a tap under 100 ms count as too soon?

Nobody can see a change and respond in less than about 100 ms. A tap that fast means you guessed when the green would come. False starts in sprinting are judged on the same idea.

Can I improve my reaction time?

A little. Good sleep, a short warm-up and full focus help the most. Practice makes you better at this particular test, but your basic reaction speed changes slowly. Experienced gamers and athletes often seem faster mainly because they read what's coming next.

Is my result saved?

Only your best average is kept, and only on this device. Nothing is sent to us. If you share a result, the link carries just your five times.