Sleep Calculator
Calculate optimal bedtime and wake time based on 90-minute sleep cycles for better rest and energy.Inputs
Example: 07:00 for 7:00 AM, 22:30 for 10:30 PM
Most people take 10-20 minutes, average is 14 minutes
Enter values to see results
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What is this?
A sleep calculator helps you time your sleep to wake up at the end of a sleep cycle, not in the middle, so you feel more refreshed. Sleep occurs in 90-minute cycles that include light sleep, deep sleep, and REM sleep. Waking between cycles feels more natural than waking mid-cycle. The average person takes 14 minutes to fall asleep, which this calculator accounts for when recommending bedtimes.How to use
Choose whether you want to wake up at a specific time or are going to bed now, enter your target wake time (if applicable) and how long you take to fall asleep, review the recommended sleep times for 3-6 complete sleep cycles, and aim for 5 cycles (7.5 hours) for optimal rest, or 6 cycles (9 hours) if you need extra recovery.Tips
- **90-minute rule:** Each sleep cycle lasts ~90 minutes. Waking at the end of a cycle feels better than waking mid-cycle.
- **Optimal sleep:** Most adults need 5-6 complete cycles (7.5-9 hours) for optimal performance.
- **Consistency matters:** Going to bed and waking up at the same time daily improves sleep quality more than extra hours.
- **Sleep debt:** You can't "make up" lost sleep on weekends. Aim for consistent 7.5-9 hours nightly.
- **Sleep latency:** If you fall asleep in under 5 minutes, you're likely sleep deprived. 10-20 minutes is healthy.
- **REM cycles:** Early cycles have more deep sleep (physical recovery), later cycles have more REM (mental recovery, memory consolidation).
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