About this calculator

• Gives recommended bedtimes if you must wake at a set hour, or wake times if you’re going to bed now.
• Uses ~90-minute sleep cycles and your settling time (minutes it takes to fall asleep).
• Highlights 5–6 cycles (7.5–9 h) as commonly restorative for adults.

How to use it

• Choose a mode: When to Sleep or When to Wake Up.
• Enter your target time (wake time or bedtime) and your time to fall asleep.
• Review several options; pick the one that fits your schedule and feels realistic.

What your result means

• Times are aligned to the end of a sleep cycle, when waking usually feels easier.
• If you wake before the alarm and feel good, it’s okay to get up—you likely finished a cycle.
• If you wake groggy, try shifting bedtime/wake time by ±15–30 minutes and keep the new time for a few days.

Tips for better sleep

• Keep a consistent schedule, even on weekends.
• Start a 30–60 min wind-down: dim lights, read, stretch, breathe.
• No screens/blue light in the last hour if you can help it.
• Keep the bedroom cool, dark, and quiet; consider white noise or earplugs.
• Avoid caffeine within 6–8 hours of bed; go easy on late alcohol.
• Get daylight soon after waking and move your body during the day.

Special situations

• Teens & young adults often need 8–10 hours.
• Shift workers: anchor 1–2 consistent sleep blocks; use blackout curtains and a wind-down routine.
• Parents & caregivers: naps (20–30 min) can help; protect your next night’s sleep by avoiding long, late naps.
• Snoring, gasping, or persistent insomnia: ask a clinician—sleep disorders are common and treatable.

FAQs

• Why 90 minutes?
  A typical cycle of light, deep, and REM sleep averages about 90 minutes, though people vary.
• Is more always better?
  Up to a point. Many adults feel best between 7–9 hours, but needs differ.
• What about naps?
  Try 20–30 minutes (easy to wake) or ~90 minutes (a full cycle). Avoid long naps late in the day.
• I take a long time to fall asleep—what should I enter?
  Add your best estimate (e.g., 20–30 minutes) so the calculator shifts bedtimes earlier.
• Medical advice?
  This is educational, not medical care. Seek help for ongoing sleep problems, excessive daytime sleepiness, or loud snoring.