Sleep Cycle Calculator
Calculate optimal bedtimes and wake times based on 90-minute sleep cycles. Choose wake-up or bedtime mode, plan naps, and get age-specific sleep recommendations from CDC/NIH guidelines. Wake up refreshed by aligning with your natural sleep cycles.
1 minute Easy
How to Use This Calculator
- Choose your mode: “I need to wake up at…” or “I’m going to bed at…”
- Set your target time (wake time or bedtime)
- Optionally adjust fall asleep time (default 15 minutes)
- Click Calculate to see optimal sleep/wake times based on 90-minute cycles
- Explore the nap calculator and sleep needs by age tabs
Sleep Mode
Wake-Up Time
min
Average is 10-20 minutes
Your Age (for recommendations)
🌙 How Sleep Cycles Work
Sleep occurs in 90-minute cycles, each containing light sleep, deep sleep, and REM (dream) stages. Waking at the end of a complete cycle — rather than in the middle of one — helps you feel refreshed and alert. Most adults need 4-6 complete cycles (6-9 hours) per night.
⏰ Recommended Sleep by Age (CDC/NIH)
- Newborns (0-3 mo): 14-17 hours
- Infants (4-11 mo): 12-15 hours
- Toddlers (1-2 yr): 11-14 hours
- Preschool (3-5 yr): 10-13 hours
- School Age (6-12 yr): 9-12 hours
- Teens (13-17 yr): 8-10 hours
- Adults (18-64 yr): 7-9 hours
- Seniors (65+ yr): 7-8 hours
💤 Nap Best Practices
- Power Nap (20 min): Light sleep only — boosts alertness without grogginess
- Short Nap (30 min): May cause sleep inertia (grogginess upon waking)
- Full Cycle (90 min): Complete cycle — wake refreshed with memory benefits
- Best time to nap: Between 1:00 PM and 3:00 PM
🔗 Save & Share Your Calculation
Your inputs are automatically saved in the URL. You can bookmark this page to save your calculation, or use the Share button to send it to others.
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