Sleep calculator
Plan your bedtime or wake-up time, with room to wind down and fall asleep.
Plan to be in bed at
10:45 PM Previous day8 hours of sleep, allowing 15 minutes to fall asleep.
- Previous dayStart winding downFollow the step-by-step plan
- Previous dayGo to bed
- Previous dayEstimated sleep starts
- Same dayWake up
A daily clock-time plan. On nights the clocks change, actual elapsed time will differ.
How it works
Bedtime = wake time − sleep duration − time to fall asleep.
Work back from your wake time, or forward from your bedtime. Wind-down time is separate from time in bed. This estimate does not account for awakenings during the night.
For example, to wake at 7:00 AM after 8 hours of sleep, with 15 minutes to fall asleep, plan to be in bed at 10:45 PM the previous day.
Sleep stages cannot be predicted from a clock alone. NIH describes cycles as typically 80–100 minutes, so we do not promise a perfect 90-minute wake-up window.
What the guidance says
CDC recommends at least 7 hours for adults 18–60, 7–9 hours at 61–64, and 7–8 hours at 65+. Your needs may differ; the calculator uses your selected duration.
Sources checked September 21, 2026. Educational scheduling tool, not a diagnosis or a treatment for sleep problems. If you regularly struggle with sleep, speak with a healthcare professional.
A few useful answers.
Are sleep cycles exactly 90 minutes?
No. NIH describes cycles as typically 80–100 minutes. A clock-based calculator cannot identify your sleep stages or guarantee that you will wake refreshed.
What time should I go to bed if I wake at 7 AM?
For an 8-hour sleep target and 15 minutes to fall asleep, plan to be in bed at 10:45 PM the previous day. With 30 minutes to wind down, begin at 10:15 PM. Adjust the inputs for your needs.
Does the calculator save my information?
Your calculations stay in the page unless you copy a link or print. A copied link contains your settings. Email signup is separate and does not include your sleep schedule.
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