BMI Calculator
Estimate adult Body Mass Index from height and weight using the World Health Organization formula. Switch between metric and imperial units, then compare your result to standard adult categories.
How the formula works
Adult BMI is weight (kg) ÷ height (m)². With imperial inputs, the equivalent is 703 × weight (lb) ÷ height (in)². Categories shown here follow common WHO adult cutoffs: underweight below 18.5, normal 18.5–24.9, overweight 25–29.9, and obesity at 30+.
BMI is a population screening estimate, not a direct measure of body fat, muscle mass, or health. It can misclassify muscular athletes and does not replace medical advice. This page is for adults; children and teens need age- and sex-specific charts.
Normal weight. Approximate healthy weight for this height: 59.9 kg – 80.7 kg.
| Category | BMI range |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obesity class I | 30.0–34.9 |
| Obesity class II | 35.0–39.9 |
| Obesity class III | 40.0+ |
Plan training around the number
BMI alone does not prescribe a workout. Use it as context, then build repeatable strength work and calorie planning with the tools below.