Sleep Calculator

Calculate optimal bedtime and wake-up times based on sleep cycles. Improve your sleep quality by waking up at the right time during your natural sleep rhythm.

Sleep Time Calculator

What would you like to calculate?

When should I go to bed?When should I wake up?How many sleep cycles will I get?

Wake-up time

Preferred sleep duration

Time to fall asleep (minutes)

Age group

Quick Presets

Sleep Quality Tips

💡Maintain a consistent sleep schedule, even on weekends

🌙Create a dark, cool, and quiet sleeping environment

📱Avoid screens 1 hour before bedtime

☕Limit caffeine intake after 2 PM

🏃Exercise regularly, but not close to bedtime

Sleep Schedule Results

Recommended Bedtimes

00:45

4 sleep cycles (6 hours)

May be too short

23:15

5 sleep cycles (7.5 hours)

Optimal for your age group

21:45

6 sleep cycles (9 hours)

Optimal for your age group

Sleep Cycle Timeline

23:15Bedtime - Start falling asleep

23:30Cycle 1 - Light Sleep

23:50Cycle 1 - Deep Sleep

00:30Cycle 1 - REM Sleep

01:00Cycle 2 - Light Sleep

01:20Cycle 2 - Deep Sleep

02:00Cycle 2 - REM Sleep

02:30Cycle 3 - Light Sleep

Personalized Recommendations

Optimal Sleep Duration

7-9 hours (maintain consistent schedule)

Sleep Debt Risk

Moderate risk - slightly sleep deprived

Chronotype Match

Good match - aligns with natural circadian rhythm

Sleep Statistics

7.8h

Time in Bed

7.5h

Actual Sleep

97%

Sleep Efficiency

25%

REM Sleep

How to Use the Sleep Calculator

Step-by-Step Instructions

Choose what you want to calculate (bedtime, wake time, or sleep cycles)
Enter your target time (wake-up time or bedtime)
Select your preferred sleep duration or let us recommend
Adjust the time it takes you to fall asleep
Choose your age group for personalized recommendations
Review the optimal sleep schedule suggestions

Understanding Sleep Cycles

Sleep Cycle: Complete cycle lasts about 90 minutes
Light Sleep: Easy to wake up, transition phase
Deep Sleep: Physical restoration, hard to wake up
REM Sleep: Mental restoration, dreaming occurs
Optimal Waking: End of a cycle for easier awakening

Sleep Science & Cycles

Sleep Stages

Stage 1 (Light Sleep): 5% of sleep time. Transition between wake and sleep. Easy to wake up.

Stage 2 (Light Sleep): 45% of sleep time. Heart rate and breathing slow down. Sleep spindles occur.

Stage 3 (Deep Sleep): 25% of sleep time. Physical restoration, immune system strengthening.

REM Sleep: 25% of sleep time. Mental restoration, memory consolidation, dreaming.

Age-Based Sleep Needs

Teenagers (14-17): 8-10 hours per night. Later bedtimes are natural.

Young Adults (18-25): 7-9 hours per night. Peak sleep efficiency.

Adults (26-64): 7-9 hours per night. Consistent schedule important.

Older Adults (65+): 7-8 hours per night. Earlier bedtimes common.

Example Sleep Schedules

Early Bird Schedule

Wake-up time: 6:00 AM

Bedtime: 10:00 PM (for 7.5 hours)

Sleep cycles: 5 complete cycles

Benefits: Aligned with natural circadian rhythm, better morning productivity

Night Owl Schedule

Wake-up time: 9:00 AM

Bedtime: 1:00 AM (for 7.5 hours)

Sleep cycles: 5 complete cycles

Benefits: Accommodates delayed sleep phase, maintains cycle integrity

Frequently Asked Questions

Why is waking up at the end of a sleep cycle important?

Waking up at the end of a sleep cycle, particularly during light sleep, makes you feel more refreshed and alert. Waking during deep sleep can cause grogginess and sleep inertia.

How accurate are 90-minute sleep cycles?

Sleep cycles typically range from 80-120 minutes, with 90 minutes being the average. Individual cycles can vary, but this provides a good baseline for planning.

What if I can't fall asleep at the recommended bedtime?

Gradually adjust your bedtime by 15-30 minutes earlier each night. Maintain good sleep hygiene and consider your natural chronotype when setting schedules.

Should I prioritize sleep duration or cycle completion?

Both are important, but completing full sleep cycles often leads to better sleep quality even with slightly less total sleep time.