Sleep Cycle Count

Plan your bedtime and wake-up alarm around natural sleep rhythms. Enter the total hours you expect to sleep and the calculator divides by the average 90-minute cycle length to show how many complete cycles you can achieve.

Include only the time you expect to be asleep, not time spent reading in bed

Educational purposes only. Not medical advice.

Examples

  • 7.5 h ⇒ 5 cycles
  • 6.0 h ⇒ 4 cycles
  • 8.0 h ⇒ 5.33 cycles
  • 9.0 h ⇒ 6 cycles

FAQ

Why 1.5 hours per cycle?

Sleep research shows most adults average about 90 minutes to move through light, deep, and REM stages.

Can I use decimals?

Yes. Enter any duration in hours—for example, 7.75 hours represents 7 hours and 45 minutes.

Does it account for falling asleep time?

No, add the time you usually need to fall asleep to your planned bedtime to stay on schedule.

What if I wake briefly during the night?

Short awakenings are common; if they last longer than a few minutes, subtract that time from the total hours before calculating.

How accurate is the cycle estimate?

Cycle length varies person to person, so treat the result as a guideline rather than a strict prescription.

Additional Information

  • A complete sleep cycle includes light sleep, deep sleep, and REM stages, averaging roughly 90 minutes in adults.
  • Sleep experts often suggest waking at the end of a cycle to minimize grogginess from sleep inertia.
  • Cycle length can vary between 70 and 110 minutes; adjust the total sleep time if you know your personal rhythm.
  • Tracking devices may provide personalized cycle data that can refine this estimate.

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