Sleep calculator
Plan a bedtime or wake-up time from your chosen sleep duration and time to fall asleep.
Your inputs
Your result
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How it works
- Bedtime is wake-up time minus sleep duration and time to fall asleep. Wake-up time adds both durations. Optional cycle estimates use your chosen cycle length; they do not detect actual sleep stages.
Assumptions and limitations
This is a planning estimate, not a prediction of sleep stages or a medical recommendation. Sleep cycles vary; the cycle length is an editable assumption. Day offsets describe clock time and do not model daylight-saving changes.
Sources
- NIH/NHLBI — sleep phases and stages Sources reviewed: 2026-10-24
