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What time should I go to bed if I wake up at 9:45 am?

Updated October 3, 2026 · Method: 90-minute cycles + 15 min to fall asleep · Sources: NINDS, AASM, NSF

Short answer

2:00 am

for 5 full cycles — 7 h 30 min of sleep, inside the 7–9 h most adults need.

Earlier, 6 cycles12:30 am9 h
Minimum, 4 cycles3:30 am6 h — short for most adults

General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.

A 9:45 am alarm is the most common one people ask about, and the answer is 2:00 am for five cycles or 12:30 am for six.

Your night if you turn the lights out at 2:00 am
12345Lights out 2:00 amWake 9:45 am15 min to fall asleep5 cycles × 90 min = 7 h 30 min

One cycle ≈ 90 min (range 70–120) · NINDS "Brain Basics: Understanding Sleep" · as of October 3, 2026

Why three times and not one

The middle option, 2:00 am, is five cycles and 7 h 30 min of actual sleep; 12:30 am is six cycles and 9 h. Both sit inside the adult range. The 3:30 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 2:00 am, asleep around 2:15 am, deepest sleep of the night between roughly 2:35 am and 3:45 am, the night's midpoint at 6:00 am, and REM building toward 9:10 am. The 9:45 am alarm lands as cycle 5 closes, so you are likely in light sleep rather than deep.

All bedtimes for a 9:45 am alarm

Lights outCyclesSleepAdult range
12:30 am69 hwithin 7–9 h
2:00 am57 h 30 minwithin 7–9 h
3:30 am46 hbelow 7 h
5:00 am34 h 30 minbelow 7 h

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 2:00 am

Two things stretch the fifteen minutes most people need to drop off: caffeine within six hours of 2:00 am (that is 8:00 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 3:30 am window.

Try a different time

Counts in 90-minute cycles plus 15 minutes to fall asleep. How we calculate

Related pages

Wake up at 9:15 ambed by 1:30 amWake up at 9:30 ambed by 1:45 amWake up at 10:00 ambed by 2:15 amWake up at 10:15 ambed by 2:30 am Going to bed at 2:00 am instead?wake at 9:45 am Nap today without wrecking tonight≤ 26 min What 5 cycles actually covers7 h 30 min

Sources

  1. Brain Basics: Understanding Sleep — National Institute of Neurological Disorders and Stroke (NIH)
  2. Sleep cycles - Sleep Education — American Academy of Sleep Medicine
  3. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the AASM and Sleep Research Society — Sleep 38(6):843-844, 2015
  4. Broadband Sound Administration Improves Sleep Onset Latency in Healthy Subjects in a Model of Sleep Onset Insomnia — Frontiers in Neurology 8:718, 2017 (Messineo L. et al.)
  5. Noise as a sleep aid: A systematic review — Sleep Medicine Reviews 55:101385, 2021 (Riedy S.M. et al.)

General information from population studies (NIH, CDC, NSF, AASM). It is not medical advice and does not replace a clinician who knows you.