What are the BMI categories?
WHO: Underweight <18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese ≥30. Asian populations use lower thresholds (Overweight ≥23).
Calculate your BMI instantly with height and weight. See your BMI category, healthy weight range, and WHO classification.
BMI = weight(kg) / height(m)². For imperial: BMI = 703 × weight(lb) / height(in)².
A 5'10" (178 cm) person weighing 170 lb (77 kg) has a BMI of 77 / 1.78² ≈ 24.4 — in the WHO 'Normal' range (18.5–24.9).
WHO: Underweight <18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese ≥30. Asian populations use lower thresholds (Overweight ≥23).
No — BMI treats muscle as fat. Athletes with high muscle mass may register 'overweight' with low body fat. Use body-fat percentage instead.
Not the same way. Children use BMI-for-age percentiles from CDC or WHO growth charts, not the adult cutoffs.
18.5–24.9 for most adults. Lowest all-cause mortality is around 22–24 in large cohort studies.
As a population screening tool, yes. As individual body-composition advice, pair it with waist-to-hip ratio and body fat percentage.
BMI can't tell muscle from fat. A muscular athlete with 10% body fat can score BMI 27 ('overweight') while being metabolically healthier than a sedentary person at BMI 22. Combine BMI with body-fat % and waist-to-hip ratio.
Multiply 18.5 and 24.9 by your height in metres squared. Example: 1.75 m → 18.5×3.0625 ≈ 57 kg to 24.9×3.0625 ≈ 76 kg is the WHO-normal range.