Best Time to Sleep and Wake Up (According to Science)

There is no single “perfect” bedtime for everyone, but science gives us clear guidelines. The best time to sleep and wake up depends on your body clock (circadian rhythm), your lifestyle, and how many hours of sleep you personally need.

Your Body Clock: Why Timing Matters

Your body runs on a roughly 24-hour rhythm called the circadian rhythm. It controls when you feel sleepy, when your body temperature drops, and when hormones like melatonin rise. If you go to bed at totally random times, your body clock gets confused – and you often wake up feeling tired, even after a long sleep.

The key is to choose a consistent sleep window: the same bedtime and wake-up time on most days. That makes it easier both to fall asleep and to wake up.

Best Time to Sleep for Most Adults

For many adults, a good target is to wake up between 6:00 and 7:30 in the morning and to sleep for 7–9 hours. That usually means going to bed between 21:30 and 23:30. If you need to wake up earlier, your ideal bedtime should move earlier as well.

A simple rule:

  • Decide when you must wake up (for work, school, kids, etc.).
  • Count back 7.5 to 9 hours in 90-minute steps (sleep cycles) to find your ideal bedtime.
  • Stick to that window for at least 1–2 weeks and see how you feel.

Sleep Cycles: Why 7.5 Hours Often Feels Better Than 8

Your brain sleeps in 90-minute cycles. Each cycle moves from light sleep into deep sleep and back to lighter stages and REM. If you wake up in the middle of a deep phase, you feel groggy and slow, even if the total time in bed looks “okay”.

That’s why many people feel best with:

  • 6 hours (4 cycles)
  • 7.5 hours (5 cycles)
  • 9 hours (6 cycles)

These times line up with full sleep cycles and make it more likely that you wake up in a lighter phase of sleep.

Use the Sleep Calculator to Find Your Best Time to Sleep

Instead of doing the math yourself, you can use the free Sleep Calculator on BestBedtime.net. Just select when you want to wake up or when you want to go to sleep, and the calculator will show you several suggested times, based on 90-minute sleep cycles and your chosen time to fall asleep.

This makes it easy to see options like “If I need to get up at 6:30, I should aim to fall asleep around 21:45 or 23:15” – so you can plan your evenings better.

How to Shift Your Sleep Schedule Gradually

If your current bedtime is far away from your ideal one, avoid changing everything at once. Your body adapts better to small steps.

  • Move your bedtime by 15–30 minutes earlier or later every few days.
  • Keep your wake-up time consistent, even on weekends, while you are adjusting.
  • Use the sleep calculator to check new bedtimes that still align with full sleep cycles.

With a bit of planning and a consistent routine, you can find a best time to sleep and wake up that supports your energy, mood, and health – instead of fighting against your body clock every morning.