What is BMI and Why Does it Matter?
Body Mass Index (BMI) is a simple numerical screening metric that uses your height and weight to estimate if you are in a healthy range. Developed in the 19th century by mathematician Adolphe Quetelet, it is used worldwide by doctors to quickly assess potential health risks associated with underweight, overweight, and obesity.
Although BMI does not directly measure body fat, it serves as a highly reliable population-level screening indicator for most adults.
The Mathematical Formulas Explained
There are two standard ways to calculate BMI depending on whether you use metric or imperial units of measurement:
- Metric System: BMI = weight (kg) / (height (m) * height (m))
- Imperial System: BMI = (weight (lbs) / (height (in) * height (in))) * 703
Note: Example: A person who weighs 70 kilograms and is 1.75 meters tall has a BMI of 22.9, which is in the healthy range.
Understanding the Official WHO Categories
The World Health Organization (WHO) classifies weight ranges based on these official BMI scores:
| BMI Range | Weight Category | Health Risk Profile |
|---|---|---|
| Below 18.5 | Underweight | Possible nutritional deficiencies |
| 18.5 - 24.9 | Healthy Weight | Minimal weight-related risk |
| 25.0 - 29.9 | Overweight | Increased risk of cardiovascular issues |
| 30.0 and above | Obese | High risk of diabetes and heart issues |
Try the Live How to Calculate BMI
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