20 Minute Timer
Set for 20 minutes. Press start — it rings when the time is up.
Free from Ticka — the reminder app that rings like an alarm, even on silent. Close this tab and the timer stops. On your phone, Ticka rings even on silent. App Store → Google Play → App Store → Google Play →
This timer runs while the tab is open. If you need it to go off when your phone is in your pocket — that part needs the app.
20-20-20: the rule for screens and eyes
Optometrists have a rule of thumb for screen work: every twenty minutes, look at something twenty feet away for twenty seconds. The point is not the exact numbers — it is that the muscle focusing your eyes has been holding one position for a long time, and holding any position for a long time is what makes it ache.
The awkward part is remembering. Eye strain builds slowly and you notice it hours later, by which time the twenty-second break would have had to happen sixty times. This is precisely the kind of thing a timer is for: it remembers a small, dull, easily-skipped action that pays off only when it is repeated.
Twenty minutes is also a workable unit for the work itself — long enough to get somewhere, short enough that stopping does not feel like abandoning anything.
If the twenty minutes are for sleep rather than screens, the nap timer adds time to fall asleep and wakes you with an alarm that starts quiet.