BMI Calculator

BMI (Body Mass Index) is a measure derived from height and weight used to screen for weight-related health risks. Formula: Metric: BMI = weight(kg) ÷ height(m)². Imperial: BMI = (weight(lbs) ÷ height(in)²) × 703. For example, a person who is 175cm tall and weighs 75kg has a BMI of 75 ÷ (1.75²) = 24.5.

For adults: under 18.5 is Underweight, 18.5–24.9 is Healthy weight, 25–29.9 is Overweight, and 30+ is Obese (Class I: 30–34.9, Class II: 35–39.9, Class III: 40+). These ranges may differ for children (who use age- and sex-specific percentile charts) and people of Asian descent (where 23+ may be considered overweight).

BMI is a useful population-level screening tool but has significant individual limitations. It cannot distinguish between muscle and fat — a muscular athlete may have a "overweight" BMI despite very low body fat. It also ignores fat distribution (abdominal fat is more dangerous than fat elsewhere). Use BMI alongside waist circumference, body fat percentage, and other health markers for a fuller picture.

Healthy weight range corresponds to BMI 18.5–24.9. For a 170cm (5'7") person: 53.4–72.0 kg (117–158 lbs). For 180cm (5'11"): 59.9–80.8 kg (132–178 lbs). Enter your height in this calculator to see the specific healthy weight range for your height.

If BMI indicates overweight or obese, consult a healthcare provider before making significant dietary or exercise changes. For underweight BMI, speaking with a doctor or dietitian is also advisable. BMI is a starting point, not a diagnosis — your healthcare provider will consider other factors.