BMI Calculator

Body Mass Index from height and weight — metric or imperial.

Units

Height (cm)

Weight (kg)

BMI categories

Under 18.5 — Underweight
18.5 – 24.9 — Normal weight
25.0 – 29.9 — Overweight
30.0 and above — Obese

These are the categories used by the World Health Organization (WHO) for adults.

About BMI

BMI is a simple ratio of weight to height squared. It is widely used as a screening tool but has known limitations — it does not account for muscle mass, bone density, age, or fat distribution. Use it as one data point, not a diagnosis.

FAQ

Is BMI accurate for athletes?: Often not. Highly muscular individuals may have a high BMI while having very low body fat. BMI does not distinguish between muscle and fat mass.
Is BMI different for children?: Yes. BMI for children uses age- and sex-specific percentiles rather than fixed category thresholds.