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BMI calculator
Disclaimer: this tool uses standardized population formulas for educational purposes only. It does not replace individual medical or nutritional assessment. Consult a healthcare professional before changing diet or exercise.
WHO classification (adults)
| BMI (kg/m²) | Category |
|---|---|
| < 18,5 | Underweight |
| 18,5 a 24,9 | Normal weight |
| 25,0 a 29,9 | Overweight |
| 30,0 a 34,9 | Obesity class I |
| 35,0 a 39,9 | Obesity class II |
| ≥ 40,0 | Obesity class III |
What BMI tells you and what it does not
BMI = weight (kg) ÷ height² (m)
Example: 70 kg at 1.70 m → 70 ÷ 2.89 = 24.2 (normal weight). BMI is a population-level screening indicator, not a diagnosis: it cannot distinguish muscle from fat (muscular athletes read as "overweight"), does not measure fat distribution (waist circumference complements it), and the WHO ranges apply to adults. Children use percentile curves by age and older adults have adjusted ranges. Range source: World Health Organization.
Last updated: · Methodology and sources