What time should I go to bed if I wake up at 1:15 am?

Waking at 1:15 am is a night-shift or early-flight schedule, and the arithmetic does not care: five cycles still means lights out at 5:30 pm, which for most people is the previous afternoon.

Why three times and not one

5:30 pm buys five cycles (7 h 30 min). If you can manage 4:00 pm, that is six cycles and 9 h — the top of the range the NSF panel recommends for adults. The 7:00 pm 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 5:30 pm, asleep around 5:45 pm, deepest sleep of the night between roughly 6:05 pm and 7:15 pm, the night's midpoint at 9:30 pm, and REM building toward 12:40 am. The 1:15 am alarm lands as cycle 5 closes, so you are likely in light sleep rather than deep.

All bedtimes for a 1:15 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 5:30 pm

Two things stretch the fifteen minutes most people need to drop off: caffeine within six hours of 5:30 pm (that is 11:30 am), 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 7:00 pm window.

Try a different time