What time should I go to bed if I wake up at 11:15 am?

Waking at 11:15 am is a late start, which means the bedtime that gives five full cycles, 3:30 am, is after midnight — fine on a day off, harder on a schedule.

Why three times and not one

The middle option, 3:30 am, is five cycles and 7 h 30 min of actual sleep; 2:00 am is six cycles and 9 h. Both sit inside the adult range. The 5:00 am option is 6 h: enough to get through the day, not enough to do it twice.

Each cycle runs light sleep, deep sleep, then REM. Ninety minutes is the average; the real figure drifts between 70 and 120 minutes, and the first cycle of the night is usually the shortest.

In clock terms: lights out 3:30 am, asleep around 3:45 am, deepest sleep of the night between roughly 4:05 am and 5:15 am, the night's midpoint at 7:30 am, and REM building toward 10:40 am. The 11:15 am alarm lands as cycle 5 closes, so you are likely in light sleep rather than deep.

All bedtimes for a 11:15 am alarm

Formula: bedtime = wake time − (cycles × 90 min) − 15 min · adult range from the NSF 2015 panel and the AASM/SRS 2015 consensus · methodology

If you can't fall asleep by 3:30 am

Two things stretch the fifteen minutes most people need to drop off: caffeine within six hours of 3:30 am (that is 9:30 pm), and a screen in the last hour. If neither applies and you are still awake twenty minutes in, get up for a while rather than lying there, and come back for the 5:00 am window.

Try a different time