Body Mass Index (BMI) is a simple measure that estimates whether a person’s weight is appropriate for their height.
Formula:
- Metric: BMI = Weight (kg) ÷ Height² (m²)
- Imperial: BMI = 703 × Weight (lb) ÷ Height² (in²)
BMI Categories (Adults):
| BMI | Category |
|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25.0–29.9 | Overweight |
| 30.0 and above | Obesity |
Example:
- Weight = 70 kg
- Height = 1.75 m
BMI = 70 ÷ (1.75 × 1.75) = 22.9, which is in the healthy weight range.
BMI is a useful screening tool, but it does not directly measure body fat or account for muscle mass, age, sex, or body composition.
If you tell me your height and weight, I can calculate your BMI and explain what it means.
Body mass index (BMI) is a person’s weight in kilograms divided by the square of height in meters.
BMI and weight category—
- underweight,
- healthy weight,
- overweight,
- obesity.
BMI is moderately correlated with measures of body fat.
BMI strongly correlated with various metabolic and disease outcomes.
A healthy weight for adults is between 18.5 and 24.9 kg/m2 (for all ethnicities except Asians, for whom the upper value of BMI is 21.8 kg/m2).
Overweight:
BMI of 25 kg/m2 or higher in adults.
Obese:
Obesity is a BMI of 30 kg/m2 or higher in adults.
Underweight:
Adults with a BMI of 18.49 kg/m2 or less are considered underweight.
Formula to calculate BMI
BMI = Weight (kg)/Height (m)²
World Health Organization (WHO) – Obesity and Overweight
https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweightCenters for Disease Control and Prevention (CDC) – Adult BMI
https://www.cdc.gov/bmi/adult-calculator/National Heart, Lung, and Blood Institute (NHLBI) – BMI
https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htmAmerican Heart Association – Healthy Weight
https://www.heart.org/National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
https://www.niddk.nih.gov/
