Sleep hygiene
Sleep Cycle Scheduler
Sleep cycles average 90 minutes, moving through light, deep, and REM stages. Waking at the end of a cycle can improve alertness. Use this tool to find ideal bedtimes or wake-up times.
Typical adults fall asleep in 10–20 minutes. Adjust to match your experience.
Recommended schedules
4 sleep cycles
Bedtime: 12:45 a.m.
Wake: 7:00 a.m.
Sleep duration ≈ 6.3 hours
5 sleep cycles
Bedtime: 11:15 p.m.
Wake: 7:00 a.m.
Sleep duration ≈ 7.8 hours
6 sleep cycles
Bedtime: 9:45 p.m.
Wake: 7:00 a.m.
Sleep duration ≈ 9.3 hours
Consider 5–6 full cycles (7.5–9 hours) for optimal recovery. Adjust bedtime or wake time to match daily demands.
How to Use This Calculator
Choose your planning mode
Either enter a wake-up time and compute ideal bedtimes, or start with your intended bedtime to project wake times.
Adjust for sleep latency
Account for how long you typically take to fall asleep so that the schedule covers full cycles.
Select a cycle count
Healthy adults often aim for 5–6 cycles (~7.5–9 hours). Short naps target 1–2 cycles to avoid grogginess.
Formula
Sleep duration = (Number of cycles × 90 minutes) + Sleep latency
Recommended cycles: 4 (6h), 5 (7.5h), 6 (9h)
For wake-time planning: Bedtime = Wake time − Duration
For bedtime planning: Wake time = Bedtime + Duration
Full Description
Sleep architecture cycles through NREM (light and deep sleep) and REM stages approximately every 90 minutes. Waking during light sleep or REM often feels more refreshing, whereas interruptions during deep sleep (slow-wave) can cause grogginess. Aligning schedules with full cycles helps match natural rhythms.
Individual needs vary—some thrive on 6 hours, others require 9. Monitor daytime energy, mood, and cognitive function to fine-tune your schedule. Pair consistent sleep/wake times with good sleep hygiene (dark, cool rooms, limited screens) for best results.
Frequently Asked Questions
What if I wake naturally before the alarm?
That often indicates you reached the end of a cycle. Consider adjusting your wake time earlier or adding a buffer so you wake with natural cues.
Do naps follow the same rules?
Yes. Aim for 20-minute power naps or ~90-minute full-cycle naps to avoid sleep inertia.
Can caffeine or alcohol disrupt cycles?
Caffeine can delay deep sleep onset; alcohol fragments REM. Adjust intake timings to maintain consistent sleep architecture.
What if I have insomnia?
Consult a sleep specialist. Cognitive behavioral therapy for insomnia (CBT-I) targets underlying issues beyond scheduling.