BMI (Body Mass Index)
Definition
A numerical value calculated from height and weight that categorizes individuals as underweight, normal weight, overweight, or obese.
Formula
BMI = weight(kg) / height(m)²Body Mass Index is a screening tool that uses height and weight to estimate body fat and categorize weight status. BMI ranges are: underweight (below 18.5), normal weight (18.5-24.9), overweight (25-29.9), and obese (30 and above).
While BMI is widely used due to its simplicity, it has notable limitations. It does not distinguish between muscle and fat mass, meaning muscular athletes may have a high BMI despite being lean. It also does not account for age, sex, ethnicity, or fat distribution.
Despite these limitations, BMI remains a useful initial screening tool for population-level health assessments. For a more complete picture of health, it should be used alongside other measures like body fat percentage, waist circumference, and waist-to-hip ratio.
Related Calculators
Related Terms
Body Fat Percentage
healthThe proportion of your total body weight that is composed of fat tissue, a more accurate indicator of fitness than weight alone.
Lean Body Mass (LBM)
healthThe total weight of your body minus all fat weight, including muscles, bones, organs, water, and other non-fat tissues.
BMR (Basal Metabolic Rate)
healthThe number of calories your body needs to perform basic life-sustaining functions at complete rest, such as breathing, circulation, and cell production.
TDEE (Total Daily Energy Expenditure)
healthThe total number of calories your body burns in a day, combining basal metabolic rate, physical activity, and the thermic effect of food.
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