How BMI Is Calculated
Body Mass Index divides your weight in kilograms by your height in meters squared (kg/m²). In imperial: BMI = (weight in lbs × 703) ÷ (height in inches)².
BMI Categories (CDC/WHO)
| Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Normal Weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese | 30.0 and above |
Why BMI Is a Flawed Measurement
BMI does not distinguish between fat mass and muscle mass. A muscular athlete may have a BMI of 28 — technically "overweight" — despite very low body fat. BMI also ignores fat distribution. Visceral fat (around the organs) is far more metabolically dangerous than subcutaneous fat, yet BMI cannot differentiate the two.
💡 Waist circumference — men under 40 inches, women under 35 inches — is a better predictor of cardiovascular risk than BMI alone. Combine both measurements for a more accurate health picture.
Better Ways to Assess Health
Waist-to-height ratio (waist should be less than half your height), metabolic blood markers (cholesterol, glucose, triglycerides), and blood pressure together provide a much clearer picture of metabolic health than BMI alone.