How to Calculate BMI — Complete Guide
BMI (Body Mass Index) is a simple body measurement calculated from weight and height. It was developed by Belgian statistician Adolphe Quetelet in 1832.
BMI Formula
BMI = weight (kg) ÷ height² (m)
Example: 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9
Or in imperial: BMI = (weight lbs ÷ height²) × 703
WHO Classification Table
- Below 18.5 — Underweight
- 18.5–24.9 — Normal weight ✅
- 25–29.9 — Overweight
- 30–34.9 — Obesity Class I
- 35–39.9 — Obesity Class II
- 40+ — Extreme obesity
BMI Limitations
BMI doesn't distinguish between muscle and fat. A muscular athlete may be classified as "overweight" despite excellent health. BMI is a screening tool — not a medical diagnosis.
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