Find out your Body Mass Index (BMI), see the classification according to the World Health Organization (WHO), and understand your ideal weight. For adults.
Official World Health Organization classification for adults.
| Classification | BMI (kg/m²) | Health risk |
|---|---|---|
| Underweight | Under 18.5 | Increased |
| Normal weight | 18.5 to 24.9 | Low |
| Overweight | 25.0 to 29.9 | Moderate |
| Obesity Class I | 30.0 to 34.9 | High |
| Obesity Class II | 35.0 to 39.9 | Very high |
| Obesity Class III | 40.0 or more | Extreme |
Simple formula, created by Adolphe Quetelet in 1832 and adopted worldwide.
BMI = weight (kg) ÷ height² (m²)
Example: 70 ÷ (1.70 × 1.70) = 24.2 kg/m²
Adults between 18 and 65 years old. For children, teens, seniors, pregnant individuals, or athletes, supplement with a professional assessment.
BMI doesn't distinguish muscle from fat. People with a lot of lean mass (athletes, bodybuilders) can have a high BMI and still be healthy.
Body fat percentage, waist circumference, and waist-to-hip ratio give a more complete picture of body composition.
Calculating your BMI once is easy. Tracking your progress is the hard part. Trainer Connect saves every measurement, generates automatic charts, and shows your progress over time.
Start for freeThis calculator is an informational tool and does not replace a medical or nutritional evaluation. If you have questions about your weight or health, consult a professional.