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.

In this guide, you will learn how to combine your internal clock, 90-minute sleep cycles and your real-world schedule. At the end, you can use the free Sleep Calculator on BestBedtime.net to turn these ideas into a simple, practical plan.

1. 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: going to bed and waking up at roughly the same times on most days. That makes it easier both to fall asleep and to wake up.

Morning types vs. evening types

Some people are clear morning types: they feel best when they go to bed early and wake up early. Others are evening types and naturally get more energy later in the day. Most people are somewhere in between. A simple test: if you had no work or school for a week, when would you fall asleep and wake up naturally? That “free schedule” is usually close to your internal clock.

2. 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.

3. 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.

Example: planning around a 7:00 AM wake-up

Imagine you need to wake up at 7:00 AM and usually fall asleep in about 15 minutes. If you aim for 5 cycles (around 7.5 hours of sleep), you would count backwards:

  • 7:00 AM minus 7.5 hours = 11:30 PM
  • minus 15 minutes to fall asleep = get in bed around 11:15 PM

If you want 6 cycles instead, you would move bedtime to around 9:45 PM. The calculator on BestBedtime.net does this math for you and shows several options so you can choose the one that fits your evening routine.

4. Match Your Sleep Schedule with Real Life

The best time to sleep and wake up is not only about biology – it also has to work with your real life. School and work start times, commuting, family routines and social activities all influence what is realistic for you.

Start by fixing your wake-up time on most days. From there, calculate and test a realistic bedtime using 5 or 6 sleep cycles. It is usually easier to adjust bedtime than to constantly shift your alarm.

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.

5. What If Your Schedule Is Very Irregular?

Some people work shifts, have young children, or travel across time zones frequently. In these cases, a perfectly stable sleep schedule is almost impossible. You can still use the same principles, just in a more flexible way:

  • Whenever possible, group your sleep into full 90-minute cycles.
  • After very short nights, plan a recovery night with more cycles soon after.
  • Use naps carefully – 20–30 minutes for a quick boost, or about 90 minutes for a full cycle.

6. 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.

  • Choose when you need to wake up on most days.
  • Select how long you usually need to fall asleep.
  • Pick one of the suggested bedtimes that fits your evening routine.

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.