Bedtime Calculator
What time should you go to bed?
Pick your wake-up time, get the bedtimes that complete 3 to 6 full sleep cycles, so your alarm doesn't pull you out of deep sleep.
Advanced settings
Most adults average 90 minutes per cycle (range: 60–120 min)
Typical sleep latency is 10–20 minutes
Enter your time and age, then tap Calculate to see your ideal sleep windows.
How to use this calculator
The simplest sleep math: count backward from your alarm in 90-minute increments.
- Enter your wake-up time. The time your alarm needs to go off, work, school, gym, or whatever sets your morning.
- Select your age band. Sleep needs change across the lifespan. The calculator highlights the recommended cycle count for adults 26–64 (5 cycles, 7.5 hours).
- Read the bedtime options. Each chip shows a bedtime that completes a different number of full cycles. The highlighted one is best for most adults; the others let you trade duration vs. wake-quality.
- Add 15 minutes to fall asleep. The calculator already factors this in, adjust it in Advanced if you take longer.
Bedtime quick-reference table
If you don't want to use the calculator, here's the quick math for common wake-up times (adults, 5-cycle target, 15 min to fall asleep):
| Wake-up time | 5-cycle bedtime (7.5h) | 6-cycle bedtime (9h) |
|---|---|---|
| 5:00 AM | 9:15 PM | 7:45 PM |
| 5:30 AM | 9:45 PM | 8:15 PM |
| 6:00 AM | 10:15 PM | 8:45 PM |
| 6:30 AM | 10:45 PM | 9:15 PM |
| 7:00 AM | 11:15 PM | 9:45 PM |
| 7:30 AM | 11:45 PM | 10:15 PM |
| 8:00 AM | 12:15 AM | 10:45 PM |
Why cycle-aligned bedtimes matter
Your brain doesn't sleep in one continuous block. It cycles through light sleep, deep sleep, and REM roughly every 90 minutes. Where your alarm catches you in the cycle matters more than the absolute number of hours.
Waking at the natural end of a cycle, when you're in light sleep or REM, feels gentle. Waking from the middle of N3 deep sleep triggers sleep inertia: 15–30 minutes of mental fog, slower reaction time, and that drugged feeling. That's why 7.5 hours of cycle-aligned sleep often feels better than 8 hours that ends in the middle of a deep-sleep phase.
How your ideal bedtime changes with age
Bedtime isn't one-size-fits-all. A teenager who genuinely needs 9 hours and has to wake at 6:30 AM should be asleep by about 9:15 PM, earlier than most teens manage, which is why teen sleep deprivation is so widespread. An adult on 7.5 hours with the same wake time has a 10:45 PM bedtime. An older adult who naturally wakes at 5:30 AM may do best going to bed around 9:30–10:00 PM.
The calculator above adjusts the recommended cycle count for your age band automatically, so the highlighted bedtime already reflects how much sleep your body needs at your stage of life. For the full breakdown of sleep needs by age, see our guide on how much sleep you actually need.
What to do if you can't fall asleep at your bedtime
If you lie awake for more than 20–30 minutes after getting into bed, the problem usually isn't the bedtime itself, it's one of a handful of upstream factors:
- Low sleep pressure. If you napped late, slept in, or were sedentary, your body simply isn't tired enough yet. Skip the late nap and get morning daylight to build a stronger sleep drive.
- Circadian mismatch. If you're a natural night owl forced into an early bedtime, your body's melatonin hasn't risen yet. Shift gradually, 15 minutes earlier per few days, and use bright morning light to pull your clock forward.
- Caffeine or alcohol. Caffeine has a 5–7 hour half-life, so an afternoon coffee is still active at bedtime. Alcohol helps you fall asleep faster but fragments the night.
- Screens and bright light. The hour before bed should be dim. Bright light suppresses the melatonin your bedtime depends on.
- An anxious, racing mind. If bedtime is when your brain starts processing the day, a wind-down routine and a "worry dump" on paper before bed both help.
Our sleep hygiene guide covers the evidence-based habits that make a consistent bedtime actually work, and our guide on what time you should go to bed goes deeper on finding and protecting your ideal time.
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Frequently Asked Questions
What time should I go to bed if I have to wake up at 6 AM?
Working backward from 6:00 AM in 90-minute cycles with 15 minutes to fall asleep: 8:45 PM (6 cycles, 9h sleep), 10:15 PM (5 cycles, 7.5h, the most common adult sweet spot), 11:45 PM (4 cycles, 6h), or 1:15 AM (3 cycles, 4.5h). Pick the option that matches your age band and feels sustainable.
What is the "ideal" bedtime for an adult?
There isn't a single ideal, your bedtime should be whatever lets you complete 5–6 full sleep cycles before your wake time, ending at the natural end of a cycle. For a 6:30 AM wake-up, that's typically 10:30–11:00 PM. Consistency matters more than the exact clock time.
Is going to bed at 10 PM better than midnight?
Earlier bedtimes generally give you more slow-wave deep sleep, which is most concentrated in the first third of the night. That said, "better" depends on your chronotype, if you're a natural night owl (Wolf chronotype), forcing a 10 PM bedtime may leave you lying awake. Aim for the earliest bedtime that lets you fall asleep within 20 minutes.
Does it matter if I go to bed at the same time every night?
Yes, significantly. Inconsistent bedtimes ("social jet lag") are associated with worse cardiometabolic markers in observational studies. A consistent bedtime within ±30 minutes keeps your circadian rhythm anchored, which improves sleep onset, deep sleep quality, and morning alertness.
I want to fall asleep faster. What should I do before bed?
The best-evidenced sleep-onset boosters: (1) dim ambient light 1–2 hours before bed, (2) keep your bedroom cool (16–19°C / 61–67°F), (3) avoid caffeine after noon, (4) avoid heavy meals within 3 hours of bed, (5) use the bed only for sleep, not work or scrolling. If sleep onset takes more than 30 minutes most nights, consider CBT-I (cognitive behavioral therapy for insomnia).
What's a "cycle-aligned" bedtime?
A bedtime calculated to end your sleep at the natural conclusion of a sleep cycle, when you're in light sleep or REM, rather than the middle of deep sleep. The calculator above does this math for you: it shows bedtimes 3, 4, 5, and 6 cycles before your wake-up, plus 15 minutes to fall asleep.