Waking up feeling tired even after a long rest? You might be waking up in the middle of a sleep cycle. Use this quick calculator to find the best times to fall asleep or wake up feeling refreshed.
Suggested times:
How It Works
A normal sleep cycle lasts about 90 minutes. During this time, your brain moves through light sleep, deep sleep, and dream sleep. If your alarm rings while you are in deep sleep, you wake up feeling groggy.
Waking up at the end of a 90-minute cycle helps your body feel rested. Most healthy adults need 5 to 6 full cycles every night, which equals 7.5 to 9 hours of total sleep.
Related Tools
- sleep calculator - Plan your overall nightly sleep schedule.
- wake up time calculator - Find the exact time to set your morning alarm.
- bedtime calculator - Pick the best time to tuck in based on your day.
Frequently Asked Questions
What is a sleep cycle?
It is a 90-minute loop where your body cycles through light, deep, and REM sleep phases.
How long does it take to fall asleep?
The average person takes about 14 to 15 minutes to fall asleep after getting into bed.
Is 6 hours of sleep enough?
Four full cycles equal 6 hours. While it works for short bursts, 7.5 to 9 hours is better for long-term focus.