Sleep Cycle Calculator
Calculate optimal bedtime/wake time based on 90-minute sleep cycles.
Sleep Cycle at a glance
Rather than repeating a single reference figure, the Sleep Cycle below personalizes it: your own measurements feed the same published equation the reference ranges are built from.You can audit the arithmetic directly: open the page source and you will find the same equation constants from the lead paragraph and the rounding step - all in a few lines of plain JavaScript.
Calculate optimal bedtime/wake time based on 90-minute sleep cycles. The page is written for people who re-measure over time: the result fits the same progress rhythm Macrition uses for weight and waist, so the number stays comparable with everything else you record.
About Sleep Cycle Calculator
Calculate optimal bedtime/wake time based on 90-minute sleep cycles.
This lifestyle calculator helps you assess and track the non-diet factors that drive long-term health. Sleep, stress, hydration, physical activity, and circadian alignment are equally important as nutrition, sometimes more so. Use this tool to identify areas for improvement and track progress over time.
Why lifestyle matters
Research consistently shows that lifestyle factors account for more variance in health outcomes than genetics. WHO Europe's synthesis of health-determinant research attributes roughly 36% of health outcomes to health behaviours, 24% to social circumstances, 22% to genetics, 11% to medical care, and 7% to the physical environment. Behaviour is the single largest share, and unlike genetics or circumstances it is the part you can act on today. Optimizing sleep, stress, hydration, and activity can dramatically improve metabolic health, cognitive performance, and longevity.
Evidence-based interventions
Each lifestyle factor has a large body of evidence supporting specific targets: 7-9 hours of sleep, 150 minutes of weekly exercise, 30 mL/kg of water, stress management practices, and consistent sleep/wake times. Use the related tools to dive deeper into each area.
Formula sources, population limits, and references for this lifestyle calculator are documented in our public methodology. Read the methodology · Medical disclaimer