Sleep Calculator
Find the best time to sleep and wake up. Based on realistic 90-minute sleep cycles to help you wake up refreshed.
You should try to wake up at one of these times:
Includes 15 minutes to fall asleep
Why calculate sleep?
Human sleep follows a predictable pattern of 90-minute cycles. Waking up in the middle of a deep sleep cycle leaves you feeling groggy and disoriented. By timing your alarm to coincide with the end of a sleep cycle, you wake up during light sleep, feeling instantly refreshed and alert.
More Energy
Wake up without the morning fog.
Productivity
Sharper focus throughout the day.
Breathe & Relax
Follow the circle's rhythm to wind down before bed.
Frequently Asked Questions
How many hours should I sleep?
Most adults need 7 to 9 hours of sleep per night. We calculate based on 90-minute sleep cycles to help you wake up feeling refreshed rather than groggy.
What is a sleep cycle?
A sleep cycle lasts about 90 minutes and consists of light sleep, deep sleep, and REM (Rapid Eye Movement) sleep. Waking up at the end of a cycle is ideal.
Is 6 hours enough?
Six hours equates to 4 full sleep cycles. While it's the minimum recommended for adults, 7.5 hours (5 cycles) is generally considered optimal for daily function.
Why do I wake up tired?
You likely woke up in the middle of a deep sleep stage. By timing your sleep to wake up at the end of a 90-minute cycle, you'll feel more alert, even with slightly less total sleep.