Health Calculators

SSubtract & Balance

❤️ Health Calculators

BMI, sleep cycles, calories — health is about balance. Adding good habits, subtracting the bad.

GEMS Connection: Health is the S in GEMS — Subtract & Add. Caloric balance (calories in minus calories out), sleep debt, BMI ratios — health math is all about addition and subtraction to find equilibrium.
Free Online Calculators

Find Your Health Calculator

BMI Calculator

Calculate your Body Mass Index using height and weight. Supports both metric and imperial units with category classification.

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Sleep Cycle Calculator

Find the optimal times to wake up based on 90-minute sleep cycles. Wake up refreshed, not in the middle of a cycle.

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Calorie Calculator

Calculate your daily calorie needs based on age, weight, height, and activity level using the Mifflin-St Jeor equation.

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Body Fat Calculator

Estimate body fat percentage using the U.S. Navy circumference method.

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Ideal Weight Calculator

Estimate ideal body weight using Robinson, Miller, Devine, and Hamwi formulas.

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Running Pace Calculator

Calculate running pace, finish time, or distance for any race or training run.

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Pregnancy Due Date Calculator

Calculate your estimated due date from LMP, conception, or ultrasound.

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Water Intake Calculator

Calculate your daily water needs based on weight, activity level, and climate.

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Macro Calculator

Calculate daily calories and protein/carbs/fat macros for your fitness goal.

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Heart Rate Zone Calculator

Find your 5 training heart rate zones using the Karvonen formula.

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