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Free sleep cycle calculator: plan bedtimes from a wake time or wake windows from when you fall asleep. Default: wake 7:00 AM, 90 min cycles → fall asleep by 10:00 PM, in bed 9:45 PM (6 cycles, ~9 h).
Last updated: May 25, 2026
Track shortfall? Sleep debt calculator
Uses the next time that clock happens after “now” in your local timezone.
Often set to 90; you can tune between 70–120.
Time from getting in bed to actually falling asleep (wake-time mode only).
wake − (6 × 90 min) = fall asleep by 10:00 PM; in bed − 15 min = 9:45 PM
6 cycles
Fall asleep by10:00 PM
Get in bed by9:45 PM
6 full cycles (~540 min sleep) before wake-up
5 cycles
Fall asleep by11:30 PM
Get in bed by11:15 PM
5 full cycles (~450 min sleep) before wake-up
4 cycles
Fall asleep by1:00 AM
Get in bed by12:45 AM
4 full cycles (~360 min sleep) before wake-up
Real sleep architecture varies; cycle length is an average. Use this to plan a consistent schedule, not to replace medical advice for sleep disorders.
Wake time used: Tuesday, May 26 • 7:00 AM
Fall asleep by 10:00 PM
In bed by 9:45 PM
Fall asleep by 11:30 PM
In bed by 11:15 PM
Fall asleep by 1:00 AM
In bed by 12:45 AM
fall_asleep_by = wake_time − (n × cycle_length_minutes)
get_in_bed_by = fall_asleep_by − wind_down_minutes
wake_at = fall_asleep_time + (n × cycle_length_minutes)
wake − (6 × 90 min) = fall asleep by 10:00 PM; in bed − 15 min = 9:45 PM
| Cycles | Time asleep | Typical use |
|---|---|---|
| 4 | 6 h (360 min) | Typical minimum for many adults |
| 5 | 7.5 h (450 min) | Common “full night” target |
| 6 | 9 h (540 min) | Long night / catch-up sleep |
Wake time used: Tuesday, May 26 • 7:00 AM
5 cycles: Fall asleep by 11:30 PM · Get in bed by 11:15 PM
5 full cycles (~450 min sleep) before wake-up
wake − (6 × 90 min) = fall asleep by 10:00 PM; in bed − 15 min = 9:45 PM
Wake time used: Tuesday, May 26 • 6:30 AM
5 cycles: Fall asleep by 11:00 PM · Get in bed by 10:40 PM
5 full cycles (~450 min sleep) before wake-up
wake − (6 × 90 min) = fall asleep by 9:30 PM; in bed − 20 min = 9:10 PM
Fall-asleep time used: Monday, May 25 • 11:00 PM
5 cycles: Wake at 6:30 AM
5 full cycles (~450 min sleep) after falling asleep
fall_asleep + (6 × 90 min) = wake at 8:00 AM
Fall-asleep time used: Tuesday, May 26 • 1:00 AM
5 cycles: Wake at 8:30 AM
5 full cycles (~450 min sleep) after falling asleep
fall_asleep + (6 × 90 min) = wake at 10:00 AM
Wake time used: Tuesday, May 26 • 6:00 AM
5 cycles: Fall asleep by 9:40 PM · Get in bed by 9:30 PM
5 full cycles (~500 min sleep) before wake-up
wake − (6 × 100 min) = fall asleep by 8:00 PM; in bed − 10 min = 7:50 PM
Wake time used: Tuesday, May 26 • 7:00 AM
5 cycles: Fall asleep by 12:20 AM · Get in bed by 12:05 AM
5 full cycles (~400 min sleep) before wake-up
wake − (6 × 80 min) = fall asleep by 11:00 PM; in bed − 15 min = 10:45 PM
Fall-asleep mode at 11:00 PM: five cycles → wake 6:30 AM (~7.5 h after sleep onset).
Wellness planning only. Snoring, choking in sleep, or unrefreshing sleep despite long hours in bed warrant professional evaluation—not calculator tweaks alone.
Share with anyone tuning their sleep schedule.
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