Sleep Cycle Calculator
Optimal wake and bed times based on full sleep cycles. Waking between cycles can reduce grogginess.
When you want to get up
Suggested bedtimes
Based on your inputs: You'll likely feel best with ~5 cycles (~7h 30m).
Recommended bedtime: 10:45 PM (previous day)
Wake refreshed around: 6:30 AM
Shareable result
- Bedtime: 10:45 PM (previous day)
- Wake time: 6:30 AM
- Cycles: 5 (~7h 30m)
- Cycle length: 90 min
Fall asleep ~15 min before these times to complete full cycles.
Previous day
Previous day
Based on average sleep research. Individual needs vary. Not medical advice.
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What is a sleep cycle?
A sleep cycle includes light sleep, deep sleep, and REM (rapid eye movement). A full cycle typically lasts about 80–110 minutes, with 90 minutes often used as an average. Our bedtime calculator 90 minute cycle uses this so you can plan when to sleep and wake. Waking at the end of a cycle—during lighter sleep—usually feels better than waking in the middle of deep sleep.
Why waking mid-cycle causes grogginess
Waking during deep sleep can cause sleep inertia: that heavy, groggy feeling that lasts minutes or longer. Your REM sleep calculator result aims to place your wake time at the end of a cycle when you're in lighter sleep, so you feel more refreshed. Ideal sleep duration for most adults is about 7–9 hours (roughly 5–6 full cycles).
How to wake up refreshed
Use this best time to sleep calculator to align your schedule with full cycles. Add 10–20 minutes for the time it takes to fall asleep. Most people do well with 5–6 cycles (about 7.5–9 hours). Track your energy with tools like our water intake calculator and calorie calculator to support overall wellness.
How chronotype affects sleep timing
Chronotype (early bird, neutral, night owl) affects when you naturally feel sleepy and alert. Early birds tend to prefer earlier bedtimes and wake times; night owls prefer later. This optimal sleep calculator adjusts its recommendation within the ideal cycle range so the suggested time fits your type. For more planning tools, see our calculator tools.
Frequently Asked Questions
What is a sleep cycle?
A full sleep cycle (about 80–110 minutes, often ~90) includes light sleep, deep sleep, and REM. Waking between cycles—when you're in lighter sleep—reduces grogginess compared to waking during deep sleep.
Why 90 minutes for a sleep cycle?
Research commonly cites an average cycle length of about 90 minutes. Cycle length varies by person (roughly 80–110 minutes). This calculator lets you adjust cycle length for a more personalized result.
How many sleep cycles should I get?
Most adults feel best with 4–6 full cycles per night (about 6–9 hours). Five to six cycles (7.5–9 hours) is often ideal. The calculator highlights the option closest to your target sleep and chronotype.
How do I wake up refreshed?
Aim to wake at the end of a cycle (lighter sleep phase). Set a wake or bedtime so you get whole cycles plus ~15 minutes to fall asleep. Avoid waking in the middle of deep sleep when possible.
What does chronotype (early bird / night owl) do?
Chronotype shifts which option we recommend: early birds favor earlier bedtimes (more cycles); night owls favor later bedtimes (fewer cycles). Neutral uses a balanced range. We then pick the option closest to your target sleep duration.
Is this sleep cycle calculator medically accurate?
This tool is based on average sleep research and typical cycle lengths (about 80–110 minutes). It is not a substitute for medical advice. If you have a sleep disorder, persistent fatigue, or health concerns, please consult a healthcare professional.
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