REM Sleep Calculator

Your details

Choose the direction of calculation.
The time you need to get up.
How long it typically takes you to fall asleep after lying down.
Used to compare your sleep duration against age-specific guidelines.
5-cycle option (recommended)5 full sleep cycles
11:16 PM

The bedtime or wake time that gives you 5 complete 90-minute cycles (7h 30m of sleep).

4-cycle option12:46 AM
6-cycle option9:46 PM
REM sleep at 5 cycles1h 53m
Deep (N3) sleep at 5 cycles1h 30m
Total sleep at 5 cycles7h 30m
Recommended hours for your age7-9 hours (Adults 18-64)
REM113
Deep (N3)90
Core (N2)225

Bedtime: 11:16 PM for your best night.

  • For 5 complete cycles (7h 30m of sleep), go to bed at 11:16 PM.
  • That gives you roughly 1h 53m of REM sleep (memory and emotional processing) and 1h 30m of deep N3 sleep (physical restoration).
  • The recommended range for your age group is 7-9 hours. Five cycles at 7.5 hours fits neatly within this range for most adults.
  • Waking mid-cycle causes sleep inertia - the groggy, heavy feeling many people mistakenly blame on "sleeping too much". Timing your alarm to a cycle boundary fixes this.

Next stepKeep a consistent schedule: going to bed and waking at the same time every day, including weekends, anchors your circadian rhythm and makes it easier to fall asleep at your chosen time.

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