How to Use This Sleep Calculator
Choose whether you want to calculate a bedtime (you know when you need to wake up) or a wake-up time (you know when you're going to bed). Enter your time and how long it typically takes you to fall asleep. The calculator suggests times aligned with 90-minute sleep cycles so you wake up between cycles, feeling more refreshed.
Understanding Sleep Cycles
A complete sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle — rather than in the middle of one — helps you feel alert and rested. Most adults need 4 to 6 full cycles (6 to 9 hours) per night.
Tips for Better Sleep
Keep a consistent sleep schedule, even on weekends. Avoid screens for 30 minutes before bed. Keep your bedroom cool (60–67 °F / 15–19 °C) and dark. Limit caffeine after early afternoon. The average person takes about 10–20 minutes to fall asleep — adjust the "time to fall asleep" field to match your experience.
Recommended Sleep Duration
The National Sleep Foundation recommends 7–9 hours for adults (ages 18–64) and 7–8 hours for older adults (65+). This calculator highlights options within that range. However, individual needs vary — pay attention to how you feel during the day to find your ideal amount.