Reaction test

1. Pick Test for a quick check or Warm-up before you play.
2. Tap the pad (or press Space). It turns amber: wait.
3. The moment it turns green, tap. Tapping early counts as "too soon" and that try is repeated.
4. Look at your median rather than your best: one lucky tap says little.

Simple reaction tasks are sensitive to how rested you are. In lab studies, sleep loss slows responses and adds lapses, and the effect builds across several short nights (Basner & Dinges, 2011 (opens in a new tab)). Simple attention is the ability most affected by short-term sleep loss (Lim & Dinges, 2010 (opens in a new tab)).

People differ a lot in how much tiredness slows them down, so we show no averages or rankings, only your own trend. Your browser, screen and input device add their own delay too, so compare times from the same setup.

• Before a session, as a warm-up for your hands and eyes.
• Late at night: if your median is well above your usual, that's a sign to stop.
• On different days, to learn what "normal" looks like for you.