Sleep Calculator
Wake up feeling more refreshed by aligning your sleep with natural sleep cycles. Each cycle lasts about 90 minutes, and waking between cycles (rather than during deep sleep) helps you feel more alert. Enter when you need to wake up to find the best bedtimes, or enter your bedtime to find optimal wake times.
How We Calculate This
Sleep cycles average 90 minutes. Time to fall asleep is added to bedtime recommendations. Quality ratings based on recommended 7-9 hours for adults.
Frequently Asked Questions
What is a sleep cycle?
A sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM (dream) sleep. Adults typically need 4-6 complete cycles per night.
How much sleep do I need?
Adults need 7-9 hours (5-6 cycles). Teenagers need 8-10 hours. Children need 9-12 hours. Older adults may need slightly less.
Why do I feel groggy when I wake up?
Waking during deep sleep causes "sleep inertia." By timing your wake time to fall between cycles, you're more likely to wake during lighter sleep and feel more alert.
Should I use the same schedule on weekends?
Yes, consistent sleep schedules help regulate your circadian rhythm. Varying your schedule can lead to "social jet lag" and poorer sleep quality.
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