Health & Wellness Tools

Scientific Wellness Equations & Medical Reference Standards

Our fitness and health calculators are designed in strict accordance with peer-reviewed medical and athletic guidelines, including standard formulas from the World Health Organization (WHO) and the National Institutes of Health (NIH).

Body Mass Index (BMI) Standards

BMI measures body fat based on height and weight, calculated as:

BMI = weight (kg) / [height (m)]^2

While BMI is a useful screening tool for general population risk groups (Underweight < 18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese >= 30), it has limitations for athletes with high muscle mass since it does not differentiate between muscle and fat. Consider combining this measurement with waist-to-hip ratio trackers.

Basal Metabolic Rate (BMR) Equations

For daily calorie planning, we use the highly accurate Mifflin-St Jeor Equation to determine your resting energy output:

Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161

This baseline rate is multiplied by an activity factor (from sedentary to highly active) to calculate your Total Daily Energy Expenditure (TDEE), the exact caloric budget needed to maintain, lose, or gain body weight safely.