Sleep Cycle Calculator
Find the best time to wake up based on 90-minute sleep cycles and your bedtime. Free sleep-cycle calculator.
Sleep
Bedtime23:00
Wake-up time (5 cycles)
06:44
4 cycles (6 h)
05:14
5 cycles (7.5 h)
06:44
6 cycles (9 h)
08:14
7 cycles (10.5 h)
09:44
FAQ
How is BMI calculated?
BMI = weight (kg) / height (m)². Example: 70 kg / (1.75 m)² = 22.9. The WHO normal range is 18.5–24.9; below that is underweight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes may show a high BMI with low body fat. It is also less reliable for teenagers, pregnant people, older adults, and very tall or short individuals.
What are the BMI categories?
Underweight: below 18.5. Normal: 18.5–24.9. Overweight: 25–29.9. Obese class I: 30–34.9; class II: 35–39.9; class III: 40+.
What is a better measure than BMI?
Body fat percentage, waist-to-height ratio (aim for under 0.5), and waist circumference give a clearer picture of health than BMI alone.
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