Health & Fitness
Sleep Cycle Calculator
Find the best times to fall asleep or wake up — based on 90-minute sleep cycles.
Average is 14 minutes
Recommended bedtimes
Going to bed at one of these times means you'll wake up at the end of a sleep cycle and feel refreshed.
9:46 PM
6 cycles · 9 hours of sleep
⭐ Recommended
11:16 PM
5 cycles · 7.5 hours of sleep
⭐ Recommended
12:46 AM
4 cycles · 6 hours of sleep
2:16 AM
3 cycles · 4.5 hours of sleep
Each cycle is ~90 minutes. We add your sleep latency (14 min) to the calculation.
Wake up at the right moment
Sleep happens in cycles of about 90 minutes — light sleep, deep sleep, REM, repeat. Waking up at the end of a cycle (during light sleep) feels much more refreshing than waking up in the middle of deep sleep, even if total hours are the same. This calculator picks bedtimes (or wake times) that align with the end of complete cycles.
Frequently Asked Questions
Why 90-minute sleep cycles?▾
Adults typically cycle through 4 sleep stages every ~90 minutes (light → deep → REM). Waking at the end of a cycle (during light sleep) feels refreshing. Waking mid-cycle (during deep sleep or REM) feels groggy — even after 8+ hours total. Aiming for full cycles helps you wake up feeling rested.
How many cycles should I get?▾
5-6 cycles (~7.5-9 hours) is ideal for most adults. 4 cycles (6 hours) is the minimum where you can still function well. 3 cycles or less = expect cognitive impairment equivalent to mild intoxication.
What if I can't fall asleep in 14 minutes?▾
The "sleep latency" of 14 min is an average for healthy adults. If yours is consistently longer (30+ min), that may indicate insomnia, anxiety, or poor sleep hygiene (caffeine late, screens before bed, irregular schedule). The calculator lets you adjust the latency input.
Should I rely on this every night?▾
No. Cycle length varies night-to-night and person-to-person (anywhere from 70-120 min). Use the calculator as a rough guide, not gospel. The bigger wins for sleep quality: consistent sleep/wake times, dark room, cool temperature (65-68°F / 18-20°C), no caffeine after 2pm.
What time should I go to bed?▾
Use the calculator above. Pick your wake time, and we show you the best bedtimes (each ~90 min apart) so you wake at the end of a cycle. Most adults need 7.5-9 hours from sleep onset.