Best bedtimes for a 7:30 AM wake-up
| Bedtime | Sleep cycles | Total sleep | Rating |
|---|---|---|---|
| 10:15 PM | 6 | 9h | Ideal |
| 11:45 PM | 5 | 7h 30m | Ideal |
| 1:15 AM | 4 | 6h | Okay |
| 2:45 AM | 3 | 4h 30m | Too short |
These times include about 15 minutes to fall asleep. If you usually drift off faster or slower, change it in the calculator below.
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Why these bedtimes work
Sleep runs in cycles of roughly 90 minutes. Each one moves from light sleep into deep sleep and then REM sleep. Waking in the middle of deep sleep leaves you groggy, while waking at the end of a cycle feels much easier.
For a 7:30 AM alarm, five cycles (11:45 PM bedtime) suits most adults. Six cycles (10:15 PM) is better for teenagers or after a run of short nights.
Questions
How many hours of sleep do I get if I go to bed at 11:45 PM and wake up at 7:30 AM?
About 7 hours and 45 minutes in bed. That includes roughly 15 minutes to fall asleep and 7.5 hours of sleep, which is 5 full 90-minute sleep cycles.
Is 1:15 AM too late to go to bed if I wake up at 7:30 AM?
It gives you 4 sleep cycles, or 6 hours of sleep. That's fine for an occasional short night, but most adults need at least 7 hours, so try to make 11:45 PM your usual bedtime.
Why does waking up at the end of a sleep cycle matter?
Waking from deep sleep causes sleep inertia, the heavy, groggy feeling that can last up to 30 minutes. Timing your alarm for the end of a cycle means you wake from lighter sleep and feel more alert.