How the wake up calculator works
Working forward from reality
The bedtime calculator plans an ideal evening; this one prices the actual one. Enter when you truly got in bed — including the doom-scrolling — and the calculator returns the wake times that complete cycles from there. It is the honest version: optimize the morning given the night you actually had.
Choosing between the options
Five cycles (7.5 hrs) fits most adult schedules and needs. Six (9 hrs) is the recovery or weekend pick. Four (6 hrs) is functional for a night or two and expensive as a habit. When forced below four, a 20-minute afternoon nap (pre-deep-sleep) recovers more than sleeping in and wrecking the next cycle anchor.
The snooze trap
Nine minutes of fragmented dozing starts a new cycle you will interrupt — the worst of both worlds. The cycle math explains why: a partial cycle re-enters deeper stages just as the alarm fires again. Set one alarm at a cycle boundary and put the phone across the room; the snooze button is a cycle interrupter with a branding problem.