FOUR WORKING CALCULATORS
Estimate energy needs, find aligned sleep timing, check a BMI/BMR reference, and set a hydration target. Every figure here is an estimate to log and compare over time — not a diagnosis.
Estimates resting energy needs (BMR) using the Mifflin-St Jeor equation, then scales it by an activity multiplier for a total daily estimate.
Limitations: population-level formula; does not account for individual muscle mass, hormones, or medical conditions.
Works backward from a wake time, or forward from a bedtime, in full ~90-minute sleep cycles — so you're less likely to wake mid-cycle.
Limitations: cycle length varies by person and night; treat results as a starting point to test.
Calculates Body Mass Index, a simple height-to-weight ratio used as a broad population screening reference.
Limitations: does not measure body composition, muscle mass, or individual health — not a diagnostic tool.
Estimates a daily fluid range from body weight, added activity time, and climate — a starting point to log against.
Limitations: individual needs vary with health conditions and medications; thirst is still the most personal signal.
The guides library covers the research and context behind sleep, metabolism, movement, and stress.
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