Sleep Calculator
Calculate optimal bedtime, analyze sleep quality factors, and get personalized recommendations for better sleep health.
Sleep Schedule
Lifestyle Factors
Optimal Sleep Schedule
Sleep Score
Overall sleep health rating
Recommended Hours
For your age group
Alternative Sleep Cycles
Each sleep cycle is approximately 90 minutes. Waking up at the end of a cycle feels more refreshing.
How it works
A sleep calculator times your bedtime or wake-up around 90-minute sleep cycles. Waking at the end of a cycle (in light sleep) feels more refreshing than waking mid-cycle (in deep sleep), so it suggests times that complete whole cycles.
Sleep cycles
Wake time = bedtime + (n × 90 min) + ~15 min to fall asleep
- 90 min
- length of one sleep cycle
- n
- number of cycles (5–6 is typical)
Worked example
- You want to wake at 6:30 AM
- Target 5 cycles (7.5 h) + 15 min to fall asleep
- Count back 7.5 h + 15 min from 6:30
Aim to be in bed around 10:45 PM.
Good to know
- Most adults need 7–9 hours; 5–6 complete cycles usually lands in that range.
- Cycle length varies by person and night, so treat the times as guidance, not a guarantee.
- A consistent schedule and a dark, cool room matter more than perfect cycle math.
Related Calculators
Frequently Asked Questions
How many hours of sleep do I need?
Sleep needs vary by age: Adults (18-64) need 7-9 hours, teens need 8-10 hours, school-age children need 9-11 hours. Quality matters as much as quantity.
What is a sleep cycle and why does it matter?
A sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up at the end of a complete cycle helps you feel more refreshed.
How can I improve my sleep quality?
Maintain consistent sleep schedule, limit screen time before bed, keep bedroom cool and dark, avoid caffeine late in day, exercise regularly but not close to bedtime, and manage stress levels.
How often should I exercise?
The WHO recommends at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week.
What is a balanced diet?
A balanced diet includes variety from all food groups: fruits, vegetables, whole grains, lean proteins, and healthy fats.
How much water should I drink?
General recommendation is 8-10 glasses (2-2.5 liters) per day, adjusted for activity level and climate.
How important is sleep?
Sleep is crucial for physical recovery, mental health, and overall wellbeing. Adults need 7-9 hours nightly.