Body Mass Index (BMI) is calculated by dividing your weight in kilograms by your height in metres squared. It was developed in the 1830s as a population-level measurement and is still the most common first-pass screening tool used in medicine today.

BMI Ranges

  • Under 18.5 — Underweight
  • 18.5 – 24.9 — Healthy weight
  • 25 – 29.9 — Overweight
  • 30 and above — Obese

Limitations of BMI

BMI does not distinguish between muscle and fat. A professional athlete may have a BMI in the "overweight" category despite having very low body fat. Conversely, someone with a "healthy" BMI can still carry a dangerous amount of visceral fat.

For a more accurate picture, consider measuring waist circumference or body fat percentage alongside BMI.