BMI Calculator

BMI (Body Mass Index) is a number calculated from your height and weight that helps assess whether you fall in a healthy weight range. The formula is simple: BMI = weight (kg) ÷ height² (m).

Developed in the 1830s by Adolphe Quetelet and adopted globally by the World Health Organization (WHO), BMI is the most widely used screening tool for weight categories — underweight, normal, overweight, and obese.

• Below 18.5 — Underweight (may indicate malnutrition or underlying conditions)
• 18.5 – 24.9 — Normal / Healthy weight
• 25.0 – 29.9 — Overweight (increased health risk)
• 30.0 – 34.9 — Obese Class I (high risk for diabetes, hypertension)
• 35.0 – 39.9 — Obese Class II (very high risk)
• 40.0 and above — Obese Class III (extremely high risk, often called "severe obesity")

BMI is a useful screening tool but has known limitations. It doesn't distinguish between muscle and fat mass — bodybuilders and athletes can have a high BMI while having low body fat. It doesn't account for bone density, fat distribution, or ethnic differences.

For Indians and other South Asians, the WHO recommends slightly lower BMI cutoffs because South Asians tend to have higher body fat percentages at the same BMI. The Indian Council of Medical Research suggests BMI 23-24.9 as overweight (instead of 25+) and 25+ as obese.

For a complete health assessment, BMI should be combined with waist circumference, body fat percentage, and overall medical evaluation.