SleepCalculator

Sleep Times: Hours and Cycles for Every Schedule

Written by Last checked August 2026
Sources:CDC - About SleepSleep Foundation - Stages of SleepAASM/SRS - Recommended Sleep Duration

Pick your bedtime and your alarm. Each page shows the real total once you subtract the time it takes to fall asleep, how many complete 90-minute cycles that is, and how far the alarm sits from a cycle boundary.

If your times are not listed, put them straight into the hours of sleep calculator.

Bedtime 9:00 PM

Bedtime 9:30 PM

Bedtime 10:00 PM

Bedtime 10:30 PM

Bedtime 11:00 PM

Bedtime 11:30 PM

Bedtime 12:00 AM

Bedtime 12:30 AM

Bedtime 1:00 AM

Bedtime 2:00 AM

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