45 Minute Timer
Set for 45 minutes. Press start — it rings when the time is up.
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.
Why lessons and workouts land on 45
The school lesson, the academic hour, the therapy session and the standard gym class all cluster around forty-five minutes, and none of them arrived there through research into attention. They arrived there through logistics: forty-five leaves fifteen minutes in the hour for moving between rooms, resetting equipment and writing notes.
That does not make it a bad number. Forty-five is long enough to teach something with a beginning and an end, and short enough that most people can stay present without a break. The institutions converged on it because it survives contact with a real schedule.
What is worth borrowing is not the interval but the fifteen minutes attached to it. Blocks of forty-five work because something else was built to happen afterwards — the transition is part of the design, not the leftover.