Sleep Calculator
Find the best time to go to bed or wake up using 90-minute sleep cycles, so you wake between cycles feeling refreshed. Works for a set time or right now.
Cycles average 90 min (70–120 min is normal).
| Time | Cycles | Time in bed | Estimated sleep |
|---|
If you experience persistent sleepiness, see a healthcare professional. This calculator is not medical advice.
Set your alarm: Alarm clock · daily calories: BMR calculator · focus blocks: Pomodoro timer.
When should I sleep or wake up?
Set a wake-up time, bedtime, or sleep right now. Each option separates total time in bed from estimated sleep, treats 90-minute cycles as an approximation, and uses an optional age to prioritize suitable durations.
FAQ
How does it work?
The tool uses approximate 90-minute cycles, then adds your fall-asleep buffer to calculate time in bed. Estimated sleep excludes that buffer.
Why several times?
Sleep cycles vary, so the table offers several schedules and orders them using your optional age-based recommendation. Pick one that also fits your real routine.
Is 90 minutes exact for everyone?
No. Cycles average 90 minutes, and 70–120 minutes is normal. Treat these times as approximate guidance, not a strict rule.
How much sleep do I need?
Ages 13–17 are generally recommended 8–10 hours, adults 18–64 need 7–9 hours, and adults 65+ need 7–8 hours.
Last updated: