Recommended bedtimes
6 cycles (~9h): 9:45 PM
5 cycles (~7.5h): 11:15 PM
4 cycles (~6h): 12:45 AM
Concept: each sleep cycle is about 90 minutes.
Sleep patterns vary between individuals.
Find the ideal bedtime or wake-up time based on 90-minute sleep cycle intervals.
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Wake-time suggestions are based on standard 90-minute cycle estimates—individual cycle length varies.
Recommended bedtimes
6 cycles (~9h): 9:45 PM
5 cycles (~7.5h): 11:15 PM
4 cycles (~6h): 12:45 AM
Concept: each sleep cycle is about 90 minutes.
Sleep patterns vary between individuals.
Find the ideal bedtime or wake-up time based on 90-minute sleep cycle intervals.
Find the best bedtime or wake-up time based on 90-minute sleep cycles. Minimize sleep inertia by waking at the end of a cycle.
Provide the values required by the tool.
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A typical sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM sleep stages. Most adults complete 4–6 cycles per night, totalling 6–9 hours.
Grogginess (sleep inertia) is often caused by waking during deep sleep rather than at a natural cycle boundary. The calculator suggests wake times aligned to cycle endpoints to reduce this effect.
Sleep time inputs are processed locally in your browser and are not sent to any server.
Wake-time suggestions are based on standard 90-minute cycle estimates—individual cycle length varies.
Educational tool only—not medical sleep advice. Health information is for educational purposes only and is not medical advice. Consult a qualified healthcare provider before making health decisions.
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Reviewed by EverydayTools Editorial Team on 2026-05-20.