Sleep Calculator

Wake up at
:
90 m90 m90 m50 m50 m90 minPER CYCLE✦✦✦✦✦
Recommended Bedtime
12:00 AM5 cycles · 7.5h★ IDEAL
10:30 PM6 cycles · 9h
01:30 AM4 cycles · 6h
03:00 AM3 cycles · 4.5h

Sleep cycles

Plan sleep around complete cycles

SleepEstimate helps you pick a bedtime or wake-up time around 90-minute sleep cycles. Choose 4, 5, or 6 cycles, then fine-tune the time with the clock arc or the time selector.

How it works

  • 4 cycles is about 6 hours of sleep.
  • 5 cycles is about 7.5 hours of sleep.
  • 6 cycles is about 9 hours of sleep.
  • A 15-minute buffer is included for falling asleep.

FAQ

What is the best time to sleep?

The best bedtime depends on when you need to wake up and how many complete sleep cycles you want. For many adults, 5 or 6 cycles is a practical target.

Why does the calculator use 90-minute cycles?

Sleep is commonly discussed in cycles of roughly 90 minutes. Real sleep varies by person, but cycle-based planning can help you avoid waking in the middle of a cycle.

Is this medical advice?

No. SleepEstimate is a general planning tool. If you have sleep problems, fatigue, insomnia, or medical concerns, talk with a qualified health professional.