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Sleep Cycle Calculator - Sleep Phases

Calculate optimal bedtime or wake time based on 90-minute sleep cycles. Includes sleep stage timing (light, deep, REM), sleep debt tracking, and circadian rhythm recommendations. Health calculator for better sleep quality and daytime alertness.

Sleep Cycle (90 minutes)

Sleep Time = Wake - (n × 90 min)

Variables:

  • nNumber of cycles (5-6 cycles ideal)
    Number of cycles (5-6 cycles ideal)
  • Cycle1 cycle = 90 minutes
    1 cycle = 90 minutes

How to Use the KalkuLab Sleep Cycle Calculator

  1. 1

    Enter Wake-Up Time

    Enter your desired wake-up time.

  2. 2

    Select Number of Cycles

    Choose the number of sleep cycles (5-6 recommended for adults).

  3. 3

    Calculate

    Get your optimal bedtime based on 90-minute sleep cycles.

Examples

Wake Up at 6 AM

Problem:

Wake at 6:00 AM with 6 cycles. What time should you go to bed?

Solution:
  1. 1.Total sleep = 6 × 90 = 540 minutes = 9 hours
  2. 2.6:00 AM - 9 hours = 9:00 PM
Result:Bedtime at 9:00 PM

Going to bed at 9 PM gives you 6 complete sleep cycles.

Frequently Asked Questions

How many sleep cycles are ideal?
5-6 cycles (7.5-9 hours) is recommended for most adults.
What is the REM phase?
REM is the deepest sleep phase for memory consolidation, occurring at the end of each sleep cycle.

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References