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Sleep Calculator

Select the time you want to wake up:
:
Calculate Bedtime

Optimal Bedtime

If you want to wake up refreshed at {{wakeupTimeStr}}, you should try to go to sleep at one of the following times:

{{item.time}}

{{item.duration}}

{{item.title}}

If you go to bed at one of the above times, you will get up in between the {{settings.timeFocus}}-minute sleep cycles, assuming it takes you {{settings.timeBreak}} minutes to fall asleep. It is recommended to have 5-6 complete cycles of sleep every night.

Select the time you want to go to bed:
Now 30 minutes later 1 hour later
Or
:
Calculate Wake-up Time

Optimal Wake-up Times

If you go to bed at {{bedTimeStr}}, consider waking up at one of the following times for optimal rest:

{{item.time}}

{{item.duration}}

{{item.title}}

If you wake up at one of the above times, you will get up in between the {{settings.timeFocus}}-minute sleep cycles, assuming it takes you {{settings.timeBreak}} minutes to fall asleep. It is recommended to have 5-6 complete cycles of sleep every night.

Sleep Cycle Length
{{settings.timeFocus}} minutes
Fall Asleep Time
{{settings.timeBreak}} minutes

Sleep Calculator – Find Your Best Time to Sleep and Wake Up Based on Science

Are you tired of waking up groggy, even after a full night’s rest? Do you struggle to fall asleep at a consistent time or feel exhausted in the morning? Not sure when to go to bed or wake up? If so, it might be time to optimize your sleep schedule using this Sleep Calculator — a powerful tool designed to help you determine the best time to sleep and wake up, based on your body’s natural sleep cycles.

This free online Sleep Calculator uses proven 90-minute sleep cycles to recommend ideal bedtimes and wake-up times for you. Just select the time you want to wake up or the time you want to go to bed and click "Calculate" button to get started.

How does this Sleep Calculator determine bedtimes?

Our sleep calculator works by counting back in 90-minute sleep cycles from your wake-up time, accounting for average time to fall asleep. You can also customize the length of each sleep cycle and the time it takes you to fall asleep according to your personal sleep patterns.

What is a 90-minute sleep cycle?

A 90-minute sleep cycle is the average length of one complete cycle through different sleep stages (light, deep, REM). Typically, the body cycles between non-REM and REM sleep over a period of 90 minutes on average, and should occur 4-6 times in a good night's sleep.Waking up at the end of a cycle helps you feel refreshed.
Optimize your sleep quality by aligning with natural 90-minute sleep cycles. Research shows that completing 5-6 full sleep cycles (7.5-9 hours) leads to better cognitive function, improved memory, and enhanced overall well-being.
Wake up feeling refreshed by timing your sleep to complete full cycles. Interrupted sleep cycles can cause grogginess, while waking between cycles promotes natural alertness and better morning performance.

How Does this Sleep Calculator Help You?

Using this Sleep Calculator helps ensure that you wake up at the end of a complete sleep cycle, rather than in the middle of deep sleep, which often leads to fatigue and confusion. Here's how it benefits you:
  • Helps you find the best time to sleep and wake up
  • Reduces morning grogginess
  • Maximizes restorative sleep
  • Encourages consistency in sleep habits
  • Supports circadian rhythm alignment
For example, if you need to wake up at 7:00 AM, the calculator may suggest going to bed at 09:45 PM, allowing for five full 90-minute cycles (plus time to fall asleep).


Getting enough sleep isn’t just about quantity — it’s about quality and timing. By using our Sleep Calculator, you’re not only optimizing your rest but also supporting your brain health, mood, and daily productivity.
So next time you set your alarm, consider using this Sleep Cycle Calculator to make sure you're waking up at the best possible moment in your sleep cycle. Wake up refreshed, energized, and ready to take on the day!

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